@article{boening-ulman_mikelonis_heckman_calfee_ratliff_youn_smith_mitchell_hunt_winston_2024, title={The potential to manage releases of <i>Bacillus anthracis</i> using bioretention and a high flow media filter: Results of simulated runoff testing with tracer spores <i>Bacillus globigii</i>}, volume={354}, ISSN={["1095-8630"]}, DOI={10.1016/j.jenvman.2024.120286}, abstractNote={The threat of bioterrorism has spurred research on the decontamination and containment of different agents. Anthrax [causative agent Bacillus anthracis (Ba)] is a disease that can lead to severe infections within human and animals, particularly when inhaled. This research investigated the use of spore-contaminated simulated runoff events into stormwater control measures (SCMs), which are designed to retain and improve the quality of runoff and may have the potential to filter and contain the spores. In this study, the effectiveness of a bioretention cell (BRC) and high flow media filter (HFMF) in Huron, Ohio, were evaluated for removal of Bacillus globigii (Bg) spores (a harmless cognate of Ba). Three 4–8 mm simulated runoff events were created for each SCM using a fire hydrant and Bg spores were injected into the runoff upstream of the SCM inlets. The BRC significantly (p < 0.001) outperformed the HFMF in reducing Bg concentrations and loads, with an average load reduction of 1.9 log (∼99% reduction) compared to 0.4 (∼60% reduction), respectively. A probable critical design factor leading to these differences was the infiltration rate of the media and subsequent retention time within the filters, which was supported by similar disparities in suspended solids reductions. Differences in spore removal may also have been due to particle size distribution of the HFMF, which was more gravelly than the bioretention cell. At 3 and 6 months after the-simulated runoff tests, soil samples taken from both SCMs, yielding detectable Bg spores within the top 15 cm of media, with increased spore concentrations where ponding occurred for longer durations during the tests. This suggests that forebays and areas near inlets may be hotspots for spore cleanup in a real-world bioterrorism incident.}, journal={JOURNAL OF ENVIRONMENTAL MANAGEMENT}, author={Boening-Ulman, Kathryn M. and Mikelonis, Anne M. and Heckman, J. Lee and Calfee, M. Worth and Ratliff, Katherine and Youn, Sungmin and Smith, Joseph S. and Mitchell, Caleb E. and Hunt, William F. and Winston, Ryan J.}, year={2024}, month={Mar} }
 @article{gee_dobyns_gage_woodward_hunt_kennedy_lehr_2022, title={EVALUATING THE OCCURRENCE AND RELATIVE ABUNDANCE OF MOSQUITOES IN RAINWATER HARVESTING SYSTEMS}, volume={65}, ISSN={["2769-3287"]}, DOI={10.13031/ja.15189}, abstractNote={
						Highlights
					}, number={6}, journal={JOURNAL OF THE ASABE}, author={Gee, Kathy DeBusk and Dobyns, Kaitlyn and Gage, Kyrsten and Woodward, Mitch and Hunt, William and Kennedy, Shawn and Lehr, David}, year={2022}, pages={1475–1487} }
 @article{moin_hunt_birgand_ratzlaff_2022, title={Effect of Visibility on Maintenance Investment and Consequent Performance of Urban Stormwater Control Measures}, volume={8}, ISSN={["2379-6111"]}, DOI={10.1061/JSWBAY.0000975}, abstractNote={Studies on the performance of urban stormwater control measures (SCMs) mainly focus on hydrologic and biological factors. SCMs are located in an urban context and humans are part of this ecosystem, yet few studies have investigated the effect of human interaction on SCM performance. While SCM designs rarely encourage physical human interaction, their placement in the urban landscape does allow visual interaction. This study explores the impact of SCM visibility on the degree of maintenance received and, consequently, on the hydrologic performance of the system. Forty SCMs, including 20 bioretention cells and 20 wetlands or wet ponds, were assessed. Visibility was evaluated through SCM surveys to determine viewshed size, noticeability, and potential passerby traffic. Hydrologic performance was evaluated through (1) visual inspection, (2) surveying vegetation health, (3) measuring drawdown rates, and (4) soil tests of bioretention media. As the degree of maintenance varied for each SCM, previous maintenance records, including cost data for the preceding year, were obtained and compared to visibility scores and hydrologic performance metrics. The study findings concluded that (1) smaller practices (bioretention) were more expensive to maintain than larger practices (ponds and wetlands) on a per SCM-area basis; and (2) the communication between the design community and the maintenance crew is essential. As an example, because they are not aware that bioretention cells (BRCs) can drain too fast for effective nitrogen treatment, maintenance crews often assume a BRC with greater than recommended drawdown rate is functioning well. The authors believe that this misunderstanding impacted whether visibility could be a predictor of hydrologic performance. Ancillary results suggest that maintenance crews tend to prioritize more visible systems; however, based on the hydrologic performance, SCM priority did not significantly affect the quality of maintenance performed. Moreover, the SCMs examined tended to perform acceptably well. This finding is considered biased because of (1) generally informed and conscientious maintenance crews, as they hold an “SCM Inspection and Maintenance Certification”; and (2) routine SCM inspection and maintenance performed on a monthly basis, which is more frequent than those reported in other studies, and therefore not reflective of SCMs found elsewhere. Further research is needed, using a greater number of maintenance crews, and controlling for crews with appropriate training, utilizing the methodology presented herein.}, number={1}, journal={JOURNAL OF SUSTAINABLE WATER IN THE BUILT ENVIRONMENT}, author={Moin, Sheida and Hunt, William F. and Birgand, Francois and Ratzlaff, Steve}, year={2022}, month={Feb} }
 @article{diab_hathaway_lisenbee_brown_hunt_2022, title={Fine scale hydrologic modelling of bioretention using DRAINMOD-urban: Verifying performance across multiple systems}, volume={614}, ISSN={["1879-2707"]}, DOI={10.1016/j.jhydrol.2022.128571}, abstractNote={Urbanization causes fundamental shifts in hydrologic partitioning within watersheds, leading to excess runoff being quickly routed to nearby conveyances. This leads to a host of concerns, from flooding to water quality impairments. To combat these effects, bioretention systems are implemented to restore more natural hydrology in the urban environment. To better understand and predict the effectiveness of these interventions, there is a need for reliable hydrology models to assess the performance of bioretention cells prior to installation. DRAINMOD-Urban was recently developed to produce hydrographs with a high temporal resolution, showing substantial promise during initial testing. Unfortunately, the dataset originally used for testing was limited, having minimal occasions of overflow and only consisting of one bioretention location. To achieve a more robust analysis of the model, DRAINMOD-Urban was evaluated using two years of monitoring data for four bioretention cells in North Carolina. The modeled bioretention cells had variable media depths, surface storage volumes, site conditions, and propensity for overflow. DRAINMOD-Urban model parameters were calibrated for a Nash-Sutcliff efficiency (NSE) from 0.14 to 0.60 for drainage and from 0.49 to 0.89 for overflow across the sites using six months of monitoring data. Model validation confirmed these results, producing drainage and overflow hydrographs with accurate timing, duration, and a range of NSEs from 0.19 to 0.60 and from 0.49 to 0.81, respectively, across the four sites. Model performance varied across sites; high drainage and overflow rates are well predicted compared to extended low rates caused by clogging issues or small storms. This study highlights the potential of DRAINMOD-Urban in modeling bioretention hydrology at a fine temporal scale under varying design configurations.}, journal={JOURNAL OF HYDROLOGY}, author={Diab, G. and Hathaway, J. M. and Lisenbee, W. A. and Brown, R. A. and Hunt, W. F.}, year={2022}, month={Nov} }
 @article{gee_schimoler_charron_woodward_hunt_2021, title={A Comparison of Methods to Address Anaerobic Conditions in Rainwater Harvesting Systems}, volume={13}, ISSN={["2073-4441"]}, DOI={10.3390/w13233419}, abstractNote={Although historically used in semi-arid and arid regions, rainwater harvesting (RWH) systems have increasingly been used in non-arid and humid regions of the world to conserve potable water and mitigate stormwater runoff. Rainfall characteristics and usage patterns of stored rainwater are distinctly different in (semi-)arid and humid regions, thus presenting a unique set of challenges with respect to their utilization. Coupled with infrequent use, the addition of nitrogen and organic matter via pollen during the spring season can lead to anaerobic conditions within storage tanks, which hinders nitrogen removal, gives stored water an offensive odor, and ultimately discourages use of the water. This study evaluated three measures that can be implemented for new and existing RWH systems to prevent the development of anaerobic conditions within storage tanks: first flush diversion, simulated use, and the continuous circulation of stored water. Study findings indicate that preventing anaerobic conditions via simulated use and recirculation (1) does not necessarily remedy the issue of poor aesthetics within rainwater storage tanks, and (2) can decrease the water quality benefits provided by these systems. Rather, preventing the introduction of pollen and particulate matter to the storage tank via a first flush diverter and minimizing disturbance of settled material in the tank appear to be the most effective methods of addressing the poor aesthetics and odor problems associated with anaerobic conditions.}, number={23}, journal={WATER}, author={Gee, Kathy DeBusk and Schimoler, Daniel and Charron, Bree T. and Woodward, Mitch D. and Hunt, William F.}, year={2021}, month={Dec} }
 @article{shaneyfelt_johnson_hunt_2021, title={Hydrologic Modeling of Distributed Stormwater Control Measure Retrofit and Examination of Impact of Subcatchment Discretization in PCSWMM}, volume={7}, ISSN={["2379-6111"]}, DOI={10.1061/JSWBAY.0000938}, abstractNote={Modifications made to the landscape during urbanization can lead to increased stormwater runoff volumes and peak flows. Low-impact development (LID) techniques and green stormwater infrastructure are implemented to minimize the effects of urbanization on downstream environments. The United States Environmental Protection Agency’s Storm Water Management Model (SWMM) can be used to simulate rainfall and runoff and evaluate the performance of existing or proposed urban water infrastructure. This study examined the performance of SWMM models developed using the Personal Computer Stormwater Management Model (PCSWMM) for a residential catchment before and after being retrofit with LID practices. Three preretrofit models at varying resolutions (low, middle, and high) and one postretrofit model were created and calibrated with observed stormwater outflow and rainfall data from a previous study in Wilmington, North Carolina. The LID retrofit included a bioretention cell bump-out and two permeable-pavement parking stalls. The uncalibrated low-resolution model was unsatisfactory for both runoff volume [Nash-Sutcliffe Efficiency (NSE) =0.49] and peak flow (NSE=−0.29) and overpredicted both with a percent bias of 65% and 70%, respectively. After calibration, the three preretrofit models all had very good agreement between observed and predicted results for runoff volume (NSE>0.95) and good agreement for peak flow (NSE>0.85). Runoff volume was still overpredicted by 23% in the middle-resolution model, but the difference in peak flows was minimal at −4%. The level of subcatchment discretization for the preretrofit models had little impact on overall model performance. Following the inclusion of LID retrofits, the postretrofit model was acceptable for event volumes (NSE=0.66) and peak flows (NSE=0.78), but overpredicted volumes by 56% and underpredicted peak flows by 10%. Using observed postretrofit data, the postretrofit model was recalibrated and greatly improved agreement between the observed and predicted data for runoff volume (NSE=0.88) while remaining acceptable for peak flow (NSE>0.78). More specifically, the calibrated postretrofit model reduced the overprediction of event volumes to 21%. These results highlight the need for observed rainfall and runoff data for both preretrofit and postretrofit calibration when modeling in SWMM.}, number={3}, journal={JOURNAL OF SUSTAINABLE WATER IN THE BUILT ENVIRONMENT}, author={Shaneyfelt, Kathryn M. and Johnson, Jeffrey P. and Hunt, William F.}, year={2021}, month={Aug} }
 @article{luell_winston_hunt_2021, title={Monitoring the Water Quality Benefits of a Triangular Swale Treating a Highway Runoff}, volume={7}, ISSN={["2379-6111"]}, DOI={10.1061/JSWBAY.0000929}, abstractNote={AbstractSwales are among the most commonly used stormwater control measures (SCMs) worldwide. In 2009, the North Carolina DOT constructed a grassed swale in Knightdale, North Carolina, in the right...}, number={1}, journal={JOURNAL OF SUSTAINABLE WATER IN THE BUILT ENVIRONMENT}, author={Luell, Stacy K. and Winston, Ryan J. and Hunt, William F.}, year={2021}, month={Feb} }
 @misc{ekka_rujner_leonhardt_blecken_viklander_hunt_2021, title={Next generation swale design for stormwater runoff treatment: A comprehensive approach}, volume={279}, ISSN={["1095-8630"]}, DOI={10.1016/j.jenvman.2020.111756}, abstractNote={Swales are the oldest and most common stormwater control measure for conveying and treating roadway runoff worldwide. Swales are also gaining popularity as part of stormwater treatment trains and as crucial elements in green infrastructure to build more resilient cities. To achieve higher pollutant reductions, swale alternatives with engineered media (bioswales) and wetland conditions (wet swales) are being tested. However, the available swale design guidance is primarily focused on hydraulic conveyance, overlooking their function as an important water quality treatment tool. The objective of this article is to provide science-based swale design guidance for treating targeted pollutants in stormwater runoff. This guidance is underpinned by a literature review. The results of this review suggest that well-maintained grass swales with check dams or infiltration swales are the best options for runoff volume reduction and removal of sediment and heavy metals. For nitrogen removal, wet swales are the most effective swale alternative. Bioswales are best for phosphorus and bacteria removal; both wet swales and bioswales can also treat heavy metals. Selection of a swale type depends on the site constraints, local climate, and available funding for design, construction, and operation. Appropriate siting, pre-design site investigations, and consideration of future maintenance during design are critical to successful long-term swale performance. Swale design recommendations based on a synthesis of the available research are provided, but actual design standards should be developed using local empirical data. Future research is necessary to identify optimal design parameters for all swale types, especially for wet swales.}, journal={JOURNAL OF ENVIRONMENTAL MANAGEMENT}, author={Ekka, Sujit A. and Rujner, Hendrik and Leonhardt, Gunther and Blecken, Godecke-Tobias and Viklander, Maria and Hunt, William F.}, year={2021}, month={Feb} }
 @article{beryani_goldstein_al-rubaei_viklander_hunt_blecken_2021, title={Survey of the operational status of twenty-six urban stormwater biofilter facilities in Sweden}, volume={297}, ISSN={["1095-8630"]}, DOI={10.1016/j.jenvman.2021.113375}, abstractNote={This study evaluates the operational status of twenty-six biofilter facilities across nine cities in Sweden, with respect to their functional design criteria, engineered design features (filter media composition, hydraulic conductivity, and drawdown time), and includes a visual inspection of the biofilter components (pre-treatment, in/outlet structures, filter media, and vegetation). These indicators were used to examine the performance level of each biofilter in achieving their design objectives set by the operators. Furthermore, it was investigated whether the biofilter facilities had been properly maintained to meet the objectives. Results indicate that the soil media used was consistent with respect to percentage sand, fines, and organic matter and comparable to design recommendations used by municipalities in other countries. The field-tested hydraulic conductivity for the biofilters ranged from 30 to 962 mm/h. This range of values, along with noticeable sediment accumulation within the biofilter indicate that not all the sites were operating optimally. Pre-treatment stages in poor condition with high volumes of sediment and litter accumulation were the primary causes for, and indicators of, low hydraulic conductivity rates. The ponding volume calculations revealed that at least 40 % of facilities did not have enough capacity to retain every-day and/or design rainfall due to design and/or construction flaws. These analyses raise concerns that, for a considerable number of the biofilters surveyed, water retention and flood protection identified by operators as prioritised objectives are not being met. This raises significant concerns about the functionality of biofilter in practice. Finally, some suggestions are given for tackling the design and maintenance problems discovered.}, journal={JOURNAL OF ENVIRONMENTAL MANAGEMENT}, author={Beryani, Ali and Goldstein, Alisha and Al-Rubaei, Ahmed Mohammed and Viklander, Maria and Hunt, William F., III and Blecken, Godecke-Tobias}, year={2021}, month={Nov} }
 @article{hunt_fassman-beck_ekka_shaneyfelt_deletic_2020, title={Designing Dry Swales for Stormwater Quality Improvement Using the Aberdeen Equation}, volume={6}, ISSN={["2379-6111"]}, DOI={10.1061/JSWBAY.0000886}, abstractNote={AbstractThis case study presents a semiempirical method for designing water quality swales to treat stormwater runoff that is an alternative to current mostly anecdotal design approaches. Water qua...}, number={1}, journal={JOURNAL OF SUSTAINABLE WATER IN THE BUILT ENVIRONMENT}, author={Hunt, W. F. and Fassman-Beck, E. A. and Ekka, S. A. and Shaneyfelt, K. C. and Deletic, A.}, year={2020}, month={Feb} }
 @article{johnson_hunt_2020, title={Field Assessment of the Hydrologic Mitigation Performance of Three Aging Bioretention Cells}, volume={6}, ISSN={["2379-6111"]}, DOI={10.1061/JSWBAY.0000925}, abstractNote={AbstractIncreasing imperviousness has driven regulation and design philosophies to offset consequent increases in runoff volumes and peak flows. Previous research has shown bioretention to reduce r...}, number={4}, journal={JOURNAL OF SUSTAINABLE WATER IN THE BUILT ENVIRONMENT}, publisher={American Society of Civil Engineers (ASCE)}, author={Johnson, Jeffrey P. and Hunt, William F.}, year={2020}, month={Nov} }
 @article{wissler_hunt_mclaughlin_2020, title={Hydrologic and water quality performance of two aging and unmaintained dry detention basins receiving highway stormwater runoff}, volume={255}, ISSN={["1095-8630"]}, DOI={10.1016/j.jenvman.2019.109853}, abstractNote={Dry detention basins (DDBs) are a type of stormwater control measure (SCM) designed to provide flood storage, peak discharge reduction, and some water quality improvement through sedimentation. DDBs are ubiquitous in the urban environment, but are expensive to maintain. In this study, two overgrown DDBs near Raleigh, NC, receiving highway runoff were monitored for up to one year to quantify their water quality and hydrologic performance. Both basins, B1 and B2, have not received vegetation maintenance since construction in 2007. Flow-weighted composite samples were collected during storm events and analyzed for nutrients (Total Phosphorus (TP), Ortho-phosphorus (OP), Ammonia-N (NH3), NO2-3-N (NOX), and Total Kjeldahl Nitrogen (TKN)), total suspended solids (TSS), and total Cd, Cu, Pb, and Zn. An annual water balance was also conducted to quantify runoff volume reduction. Despite low influent concentrations from the highway, significant removal efficiencies were found for all constituents except NH3 in B1. TP, OP, NOX, TSS, and Zn were reduced in B2. Both basins achieved greater than 41% volume reduction through soil infiltration and evapotranspiration, resulting in significant pollutant load reductions for all detected constituents, between 59% and 79% in B1 and 35% and 81% in B2. This study provides evidence that overgrown and unmaintained DDBs can reduce pollutant concentrations comparable to those reported for maintained DDBs, while reducing more volume than standard DDBs. Moreover, carbon sequestration likely increases while maintenance costs decrease.}, journal={JOURNAL OF ENVIRONMENTAL MANAGEMENT}, author={Wissler, Austin D. and Hunt, William F. and McLaughlin, Richard A.}, year={2020}, month={Feb} }
 @article{gee_hunt_peacock_woodward_arellano_2020, title={Using Irrigation to Increase Stormwater Mitigation Potential of Rainwater Harvesting Systems}, volume={6}, ISSN={["2379-6111"]}, DOI={10.1061/JSWBAY.0000913}, abstractNote={AbstractRainwater harvesting (RWH) systems used for irrigation often provide fewer stormwater management benefits than systems used for year-round, nondiscretionary purposes because there is dimini...}, number={2}, journal={JOURNAL OF SUSTAINABLE WATER IN THE BUILT ENVIRONMENT}, author={Gee, K. D. and Hunt, W. F. and Peacock, C. H. and Woodward, M. D. and Arellano, C.}, year={2020}, month={May} }
 @article{wissler_hunt_mclaughlin_2020, title={Water Quality and Hydrologic Performance of Two Dry Detention Basins Receiving Highway Stormwater Runoff in the Piedmont Region of North Carolina}, volume={6}, ISSN={["2379-6111"]}, DOI={10.1061/JSWBAY.0000915}, abstractNote={AbstractDry detention basins (DDBs) are a stormwater control measure (SCM) designed to provide flood storage, peak discharge abatement, and some water quality improvement through sedimentation; how...}, number={2}, journal={JOURNAL OF SUSTAINABLE WATER IN THE BUILT ENVIRONMENT}, author={Wissler, Austin D. and Hunt, William F. and McLaughlin, Richard A.}, year={2020}, month={May} }
 @article{winston_arend_dorsey_hunt_2020, title={Water quality performance of a permeable pavement and stormwater harvesting treatment train stormwater control measure}, volume={2}, ISSN={["2617-4782"]}, DOI={10.2166/bgs.2020.914}, abstractNote={Abstract}, number={1}, journal={BLUE-GREEN SYSTEMS}, author={Winston, Ryan J. and Arend, Kristi and Dorsey, Jay D. and Hunt, William F.}, year={2020}, month={Jan}, pages={91–111} }
 @article{purvis_winston_hunt_lipscomb_narayanaswamy_mcdaniel_lauffer_libes_2019, title={Evaluating the Hydrologic Benefits of a Bioswale in Brunswick County, North Carolina (NC), USA}, volume={11}, ISBN={2073-4441}, DOI={10.3390/w11061291}, abstractNote={Bioswales are a promising stormwater control measure (SCM) for roadway runoff management, but few studies have assessed performance on a field scale. A bioswale is a vegetated channel with underlying engineered media and a perforated underdrain to promote improved hydrologic and water quality treatment. A bioswale with a rip-rap lined forebay was constructed along state highway NC 211 in Bolivia, North Carolina, USA, and monitored for 12 months. Thirty-seven of the 39 monitored rain events exfiltrated into underlying soils, resulting in no appreciable overflow or underdrain volume. The bioswale completely exfiltrated a storm event of 86.1 mm. The one event to have underdrain-only flow was 4.8 mm. The largest and third-largest rainfall depth events (82.6 and 146 mm, respectively) had a large percentage (85%) of volume exfiltrated, but also had appreciable overflow and underdrain volumes exiting the bioswale, resulting in no peak flow mitigation. Overall, this bioswale design was able to capture and manage storms larger than the design storm (38 mm), showing the positive hydrologic performance that can be achieved by this bioswale. The high treatment capabilities were likely due to the high infiltration rate of the media and the underlying soil, longer forebay underlain with media, gravel detention layer with an underdrain, and shallow slope.}, number={6}, journal={WATER}, author={Purvis, Rebecca A. and Winston, Ryan J. and Hunt, William F. and Lipscomb, Brian and Narayanaswamy, Karthik and McDaniel, Andrew and Lauffer, Matthew S. and Libes, Susan}, year={2019}, month={Jun} }
 @article{taguchi_carey_hunt_2019, title={Field Monitoring of Downspout Disconnections to Reduce Runoff Volume and Improve Water Quality along the North Carolina Coast}, volume={5}, ISSN={["2379-6111"]}, DOI={10.1061/JSWBAY.0000872}, abstractNote={AbstractVirtually all land development increases stormwater runoff and disrupts the natural hydrologic cycle. This is a particularly important issue for areas developed prior to the widespread appl...}, number={1}, journal={JOURNAL OF SUSTAINABLE WATER IN THE BUILT ENVIRONMENT}, author={Taguchi, Vinicius J. and Carey, Erin S. and Hunt, William F., III}, year={2019}, month={Feb} }
 @article{winston_powell_hunt_2019, title={Retrofitting a grass swale with rock check dams: hydrologic impacts}, volume={16}, ISSN={["1744-9006"]}, DOI={10.1080/1573062X.2018.1455881}, abstractNote={Abstract The hydrologic performance of a grass swale, a common stormwater control measure often utilized to drain roads, may potentially be improved using simple retrofits. Two rock check dams were retrofitted into an existing grass swale located in Knightdale, North Carolina, USA. The swale was monitored before and after check dam installation, and the addition of check dams improved runoff volume reduction (17%), peak flow mitigation, and hydraulic retention time in the swale, particularly for small (< 19 mm) and moderate (19–38 mm) rainfall events. The check dams were effective filters of gross solids, which eventually led to clogging and caused extended inundation and subsequent loss of swale vegetation. Because check dams are relatively inexpensive and simple vis-à-vis other stormwater control measure enhancements, their use for stormwater treatment is encouraged, provided they are adequately maintained.}, number={6}, journal={URBAN WATER JOURNAL}, author={Winston, Ryan J. and Powell, Jacob T. and Hunt, William F.}, year={2019}, month={Jul}, pages={404–411} }
 @article{purvis_winston_hunt_lipscomb_narayanaswamy_mcdaniel_lauffer_libes_2018, title={Evaluating the water quality benefits of a bioswale in Brunswick County, North Carolina (NC), USA}, volume={10}, number={2}, journal={Water}, author={Purvis, R. A. and Winston, R. J. and Hunt, W. F. and Lipscomb, B. and Narayanaswamy, K. and McDaniel, A. and Lauffer, M. S. and Libes, S.}, year={2018} }
 @inproceedings{newman_rodríguez_hunt_2018, title={History and Heritage}, ISBN={9780784481394}, url={http://dx.doi.org/10.1061/9780784481394.010}, DOI={10.1061/9780784481394.010}, abstractNote={This paper recounts the remarkable story of how the drainage of a lead mine by Cornelius Vermuyden was the driver to both legal changes and changes in mining practice which encouraged the establishment of water powered cotton spinning in the lower Derwent Valley in Derbyshire, England. It describes the development of the first three mills built by Sir Richard Arkwright including the early reliance on mine drainage water for power and Arkwright’s magnificent Masson Mill at Matlock Bath which provided a major step change in mill design. It will document the establishment of competition and developments of mill design further down the valley which greatly influenced high building design. It also recalls how the famous Samuel Slater became known locally as Slater the Traitor when he illegally travelled to the USA, to help with the technical problems being experienced by an existing mill owner, and later, to establish his own mills in the USA.}, booktitle={World Environmental and Water Resources Congress 2018}, publisher={American Society of Civil Engineers}, author={Newman, Alan P. and Rodríguez, Ángel Martín and Hunt, William F.}, year={2018}, month={May} }
 @article{winston_dorsey_smolek_hunt_2018, title={Hydrologic Performance of Four Permeable Pavement Systems Constructed over Low-Permeability Soils in Northeast Ohio}, volume={23}, ISSN={1084-0699 1943-5584}, url={http://dx.doi.org/10.1061/(ASCE)HE.1943-5584.0001627}, DOI={10.1061/(ASCE)HE.1943-5584.0001627}, abstractNote={AbstractPermeable pavements benefit urban hydrology through detention of stormwater in the aggregate base and subsequent exfiltration to the underlying soil. The majority of previous research has f...}, number={4}, journal={Journal of Hydrologic Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Winston, Ryan J. and Dorsey, Jay D. and Smolek, Alessandra P. and Hunt, William F.}, year={2018}, month={Apr}, pages={04018007} }
 @article{smolek_anderson_hunt_2018, title={Hydrologic and Water-Quality Evaluation of a Rapid-Flow Biofiltration Device}, volume={144}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001275}, DOI={10.1061/(ASCE)EE.1943-7870.0001275}, abstractNote={AbstractManufactured treatment devices (MTDs) are increasingly installed to treat pollutants from stormwater in urban areas, but few peer-reviewed studies have assessed their field-scale performanc...}, number={2}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Smolek, Alessandra P. and Anderson, Andrew R. and Hunt, William F., III}, year={2018}, month={Feb}, pages={05017010} }
 @article{braswell_anderson_hunt_2018, title={Hydrologic and water quality evaluation of a permeable pavement and biofiltration device in series}, volume={10}, number={1}, journal={Water}, author={Braswell, A. S. and Anderson, A. R. and Hunt, W. F.}, year={2018} }
 @article{braswell_winston_hunt_2018, title={Hydrologic and water quality performance of permeable pavement with internal water storage over a clay soil in Durham, North Carolina}, volume={224}, ISSN={["1095-8630"]}, DOI={10.1016/j.jenvman.2018.07.040}, abstractNote={Permeable pavement is an effective tool for improving stormwater hydrology and water quality when sited over soils with high infiltration rates, but its efficacy over less permeable soils is uncertain. This study examined permeable pavement performance when built over a low-conductivity, clay soil. Four parking stalls (50 m2 total area) were retrofitted with permeable interlocking concrete pavement (PICP) to treat 15.2 m2 of contributing impervious area (0.3:1 run-on ratio). Using an elevated underdrain, the site incorporated a 150-mm internal water storage (IWS) zone to increase exfiltration and promote anaerobic conditions for denitrification. From March 2014-April 2015, 22% of influent runoff volume was reduced via exfiltration and evaporation. Inter-event drawdown of the IWS zone created storage to capture and exfiltrate more than 70% of the runoff volume from precipitation events less than 8 mm, and peak flows were significantly reduced (median 84%). Relative to stormwater runoff from a nearby impermeable asphalt reference watershed, the permeable pavement produced significantly lower event mean concentrations (EMCs) of all pollutants except nitrate, which was significantly higher. Permeable pavement effluent and reference watershed runoff were 99%, 68%, and 96% different for total suspended solids (TSS), total nitrogen (TN), and total phosphorus (TP), respectively. Significantly lower permeable pavement effluent EMCs for copper (Cu, 79%), lead (Pb, 92%) and zinc (Zn, 88%) were also observed. The median effluent concentrations of TN (0.52 mg/L), TP (0.02 mg/L), and TSS (7 mg/L) were all very low relative to the literature. Sampling of nitrogen species in the IWS zone 12, 36, 60, and 84 h post-rainfall was done to better understand mechanisms of nitrogen removal in permeable pavement; results indicated denitrification may be occurring in the IWS zone. Effluent pollutant load from the permeable pavement was at minimum 85% less than from nearby untreated asphalt runoff for TP, TSS, Cu, Pb, and Zn, and was 73% less for TN. Permeable pavements built over low-permeability soils with internal water storage can considerably improve long-term hydrology and water quality.}, journal={JOURNAL OF ENVIRONMENTAL MANAGEMENT}, author={Braswell, Alessandra S. and Winston, Ryan J. and Hunt, William F.}, year={2018}, month={Oct}, pages={277–287} }
 @article{koryto_hunt_arellano_page_2018, title={Performance of Regenerative Stormwater Conveyance on the Removal of Dissolved Pollutants: Field Scale Simulation Study}, volume={144}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001374}, DOI={10.1061/(ASCE)EE.1943-7870.0001374}, abstractNote={AbstractRegenerative stormwater conveyance (RSC) is a stormwater control measure (SCM) built in a channel that uses a series of riffles, grade control structures, and pools with an underlying sand ...}, number={6}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Koryto, Kevin M. and Hunt, William F. and Arellano, Consuelo and Page, Jonathan L.}, year={2018}, month={Jun}, pages={04018039} }
 @article{stillwell_hunt_page_baird_kennedy_2018, title={Stormwater management in nutrient-sensitive watersheds: a case study investigating impervious cover limits and pollutant-load regulations}, volume={78}, ISSN={["1996-9732"]}, DOI={10.2166/wst.2018.338}, abstractNote={Abstract}, number={3}, journal={WATER SCIENCE AND TECHNOLOGY}, author={Stillwell, Charles C. and Hunt, William F., III and Page, Jonathan L. and Baird, Joshua B. and Kennedy, Shawn G.}, year={2018}, month={Aug}, pages={664–675} }
 @article{chenoweth_anderson_kumar_hunt_chimbwandira_moore_2018, title={The interrelationship of green infrastructure and natural capital}, volume={75}, ISSN={["1873-5754"]}, DOI={10.1016/j.landusepol.2018.03.021}, abstractNote={The terms green infrastructure and natural capital are interrelated. Natural capital as a concept is focused upon environmental assets which can provide ecosystem services, either directly or indirectly to humans; the concepts of natural capital and ecosystem services emphasize the benefits humans obtain from the natural environment. Green infrastructure is a concept with a wide range of definitions. The term is sometimes applied to networks of green open spaces found in or around urban areas. In other contexts green infrastructure can describe alternative engineering approaches for storm water management, with co-benefits of temperature control, air quality management, wildlife habitats and/or recreation and amenity space. No environments are completely free of human influence and therefore no environments are entirely natural. Rather, there is a spectrum of degrees of ‘naturalness’ ranging from environments with minimal human influence through to built environments. A trio of case studies presented herein illustrates how green infrastructure projects are a practical application of the natural capital concept in that they seek to preserve and enhance natural capital via a management approach which emphasizes the importance of environmental systems and networks for the direct provision of ecosystem services to human populations. Natural capital forms critical components of all green infrastructure projects.}, journal={LAND USE POLICY}, author={Chenoweth, Jonathan and Anderson, Andrew R. and Kumar, Prashant and Hunt, W. F. and Chimbwandira, Sarah Jane and Moore, Trisha L. C.}, year={2018}, month={Jun}, pages={137–144} }
 @inproceedings{newman_rodriguez_hunt_2018, title={Vermuyden, Arkwright, and Slater the Traitor: Derwent Valley Mills-Birthplace of the water powered cotton spinning industry and skyscraper construction techniques}, booktitle={World Environmental and Water Resources Congress 2018: International Perspectives, History and Heritage, Emerging Technologies, and Student Papers}, author={Newman, A. P. and Rodriguez, A. M. and Hunt, W. F.}, year={2018}, pages={87–100} }
 @article{cizek_hunt_winston_waickowski_narayanaswamy_lauffer_2018, title={Water Quality and Hydrologic Performance of a Regenerative Stormwater Conveyance in the Piedmont of North Carolina}, volume={144}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001344}, DOI={10.1061/(ASCE)EE.1943-7870.0001344}, abstractNote={AbstractRegenerative stormwater conveyance (RSC) is an open-channel, sand-filtering system composed of a series of shallow aquatic pools, riffles and weirs, native vegetation, and underlying media ...}, number={8}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Cizek, Adrienne R. and Hunt, William F. and Winston, Ryan J. and Waickowski, Sarah E. and Narayanaswamy, Karthik and Lauffer, Matthew S.}, year={2018}, month={Aug}, pages={04018062} }
 @article{merriman_hathaway_burchell_hunt_2017, title={Adapting the relaxed tanks-in-series model for stormwater wetland water quality performance}, volume={9}, number={9}, journal={Water}, author={Merriman, L. S. and Hathaway, J. M. and Burchell, M. R. and Hunt, W. F.}, year={2017} }
 @article{shaneyfelt_anderson_kumar_hunt_2017, title={Air quality considerations for stormwater green street design}, volume={231}, ISSN={["1873-6424"]}, DOI={10.1016/j.envpol.2017.08.081}, abstractNote={Green streets are increasingly being used as a stormwater management strategy to mitigate stormwater runoff at its source while providing other environmental and societal benefits, including connecting pedestrians to the street. Simultaneously, human exposure to particulate matter from urban transportation is of major concern worldwide due to the proximity of pedestrians, drivers, and cyclists to the emission sources. Vegetation used for stormwater treatment can help designers limit the exposure of people to air pollutants. This goal can be achieved through the deliberate placement of green streets, along with strategic planting schemes that maximize pollutant dispersion. This communication presents general design considerations for green streets that combine stormwater management and air quality goals. There is currently limited guidance on designing green streets for air quality considerations; this is the first communication to offer suggestions and advice for the design of green stormwater streets in regards to their effects on air quality. Street characteristics including (1) the width to height ratio of the street to the buildings, (2) the type of trees and their location, and (3) any prevailing winds can have an impact on pollutant concentrations within the street and along sidewalks. Vegetation within stormwater control measures has the ability to reduce particulate matter concentrations; however, it must be carefully selected and placed within the green street to promote the dispersion of air flow.}, journal={ENVIRONMENTAL POLLUTION}, author={Shaneyfelt, Kathryn M. and Anderson, Andrew R. and Kumar, Prashant and Hunt, William F., III}, year={2017}, month={Dec}, pages={768–778} }
 @article{winston_hunt_2017, title={Characterizing Runoff from Roads: Particle Size Distributions, Nutrients, and Gross Solids}, volume={143}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001148}, DOI={10.1061/(ASCE)EE.1943-7870.0001148}, abstractNote={AbstractParticulate matter, nutrients, and gross solids from roads contribute nonpoint-source pollution to waterways. To inform road runoff management, a field monitoring study was undertaken at eight road sites across North Carolina. Particle size distributions (PSD) of edge-of-pavement runoff samples were analyzed to understand the granulometry of the particulate matter. Knowledge of PSDs is critical when attempting to understand sediment fate and transport through stormwater control measures (SCMs), especially when the primary removal mechanism is particle settling. For 43 road runoff events, median particle size varied from 31 to 144 μm. The median PSD from hot mix asphalt (HMA) was 2.6% clay, 44.8% silt, and 52.6% sand. PSD was not correlated to roadway classification or ecoregion; however, PSD was significantly correlated to the presence of a permeable friction course (PFC) overlay, which is a layer of porous asphalt placed over traditional HMA. The median d90 for PFC (131 μm) was significantly smal...}, number={1}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Winston, R. J. and Hunt, W. F.}, year={2017}, month={Jan}, pages={04016074} }
 @article{merriman_moore_wang_osmond_al-rubaei_smolek_blecken_viklander_hunt_2017, title={Evaluation of factors affecting soil carbon sequestration services of stormwater wet retention ponds in varying climate zones}, volume={583}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2017.01.040}, abstractNote={The carbon sequestration services of stormwater wet retention ponds were investigated in four different climates: U.S., Northern Sweden, Southern Sweden, and Singapore, representing a range of annual mean temperatures, growing season lengths and rainfall depths: geographic factors that were not statistically compared, but have great effect on carbon (C) accumulation. A chronosequence was used to estimate C accumulations rates; C accumulation and decomposition rates were not directly measured. C accumulated significantly over time in vegetated shallow water areas (0–30 cm) in the USA (78.4 g C m− 2 yr− 1), in vegetated temporary inundation zones in Sweden (75.8 g C m− 2 yr− 1), and in all ponds in Singapore (135 g C m− 2 yr− 1). Vegetative production appeared to exert a stronger influence on relative C accumulation rates than decomposition. Comparing among the four climatic zones, the effects of increasing rainfall and growing season lengths (vegetative production) outweighed the effects of higher temperature on decomposition rates. Littoral vegetation was a significant source to the soil C pool relative to C sources draining from watersheds. Establishment of vegetation in the shallow water zones of retention ponds is vital to providing a C source to the soil. Thus, the width of littoral shelves containing this vegetation along the perimeter may be increased if C sequestration is a design goal. This assessment establishes that stormwater wet retention ponds can sequester C across different climate zones with generally annual rainfall and lengths of growing season being important general factors for C accumulation.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Merriman, L. S. and Moore, T. L. C. and Wang, J. W. and Osmond, D. L. and Al-Rubaei, A. M. and Smolek, A. P. and Blecken, G. T. and Viklander, M. and Hunt, W. F.}, year={2017}, month={Apr}, pages={133–141} }
 @article{cizek_hunt_winston_lauffer_2017, title={Hydrologic Performance of Regenerative Stormwater Conveyance in the North Carolina Coastal Plain}, volume={143}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001198}, DOI={10.1061/(ASCE)EE.1943-7870.0001198}, abstractNote={AbstractRegenerative stormwater conveyance (RSC) is an open channel, sand-filtering system composed of a series of shallow aquatic pools, riffle weirs, native vegetation, and underlying media beds....}, number={9}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Cizek, Adrienne R. and Hunt, William F. and Winston, Ryan J. and Lauffer, Matthew S.}, year={2017}, month={Sep}, pages={05017003} }
 @article{koryto_hunt_page_2017, title={Hydrologic and water quality performance of regenerative stormwater conveyance installed to stabilize an eroded outfall}, volume={108}, ISSN={["1872-6992"]}, DOI={10.1016/j.ecoleng.2017.04.041}, abstractNote={Conveying concentrated urban runoff to outfall locations frequently leads to stream bank erosion, channel incision, and the formation of headcuts. Installed in an incised eroded channel, regenerative stormwater conveyance (RSC) is a grade-control and treatment system that uses a series of pools and cascades with an underlying sand bed. As a recently developed practice, RSC performance evaluations are needed to improve the design and guide regulatory accreditation. An eroded channel with a 10% longitudinal slope was stabilized with a five-cell system and monitored for a 14-month period. A small capture volume (6-mm design event) and groundwater intrusion resulted in minimal hydrologic benefit. Hydrologic mitigation was attained only for storms less than 12.7 mm. The RSC converted a substantial 50% of inflow to media flow at the second cell; however, the media flow entirely reemerged as surface flow in the saturated downstream pools. Small but statistically significant reductions in event mean concentrations occurred: 17% total suspended sediment (TSS), 17% total phosphorus (TP), and 3% total nitrogen (TN). Water quality improvements occurred primarily between the upstream and second cell, indicating limited processing by the wetter downstream pools. Comparisons between inter-event outflow grab samples and storm event outflow concentrations show nitrogen export during inter-event periods (47% increase in TN concentration). Due to elevated inter-event concentrations, overall mass loading of nitrogen increased. Hydrologic and water quality benefits were garnered only in the first three cells where groundwater intrusion was minimal. Future implementations of RSC are encouraged to account for seasonal high water table elevations that interact with the RSC media and adequately size pool and sand layer capture volumes.}, journal={ECOLOGICAL ENGINEERING}, author={Koryto, Kevin M. and Hunt, William F. and Page, Jonathan L.}, year={2017}, month={Nov}, pages={263–276} }
 @article{winston_anderson_hunt_2017, title={Modeling Sediment Reduction in Grass Swales and Vegetated Filter Strips Using Particle Settling Theory}, volume={143}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001162}, DOI={10.1061/(ASCE)EE.1943-7870.0001162}, abstractNote={AbstractTwo of the most common and simple stormwater control measures are swales and filter strips. However, an overly simplistic one-size-fits-all design approach typically is used for these practices. To provide more flexibility in design, a coupled hydraulics and particle-settling model was created to predict swale and filter strip total suspended solids (TSS) reduction as a function of catchment area, longitudinal slope, side slope, cross section type (triangular swale, trapezoidal swale, or filter strip), and length. The hydraulics and hydrology models were based on Manning’s equation and the rational method, respectively, with the underlying requirement that the water quality design storm does not exceed the height of the grass. The particle-settling model was underpinned by the Aberdeen equation. The model predicts that triangular swales produce the least and filter strips the most TSS removal because of increased hydraulic retention time; trapezoidal swales had on average 10% greater TSS removal t...}, number={1}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Winston, Ryan J. and Anderson, Andrew R. and Hunt, William F.}, year={2017}, month={Jan}, pages={04016075} }
 @article{turk_kraus_hunt_carmen_bilderback_2017, title={Nutrient Sequestration by Vegetation in Bioretention Cells Receiving High Nutrient Loads}, volume={143}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0001158}, abstractNote={AbstractBioretention plant selection for nutrient removal (and even basic plant survival) is an understudied and not-well-understood component of this stormwater control measure. Twelve bioretention cells were constructed to evaluate 16 plants growing in three different media for their ability to remove nutrient pollution from urban stormwater runoff with high nutrient loads. Plants evaluated were pairs of natives and cultivars and included trees (Magnolia and Betula), shrubs (Viburnum and Itea), herbaceous perennial flowers (Helianthus and Eupatorium), a rush (Juncus), and an ornamental grass (Panicum). Eleven of the 16 species (B. nigra; B. Dura-Heat; M. virginiana; M. Sweet Thing; I. virginica; I. Henry’s Garnet; J. effusus; P. Shenandoah; H. angustifolius; H. First Light; and E. Gateway) performed well (grew and were aesthetically acceptable) in the bioretention cells and can be recommended as bioretention plants. Species and cultivar impacted the levels of remediation of the high N and P loads applie...}, number={2}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Turk, R. P. and Kraus, H. T. and Hunt, W. F. and Carmen, N. B. and Bilderback, T. E.}, year={2017}, month={Feb} }
 @article{winston_hunt_pluer_2017, title={Nutrient and Sediment Reduction through Upflow Filtration of Stormwater Retention Pond Effluent}, volume={143}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001195}, DOI={10.1061/(ASCE)EE.1943-7870.0001195}, abstractNote={AbstractWet ponds have often been installed to detain runoff with the intention of mitigating peak flow. However, significant current drivers exist to improve their ability to mitigate pollutants, ...}, number={5}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Winston, Ryan J. and Hunt, William F. and Pluer, William T.}, year={2017}, month={May}, pages={06017002} }
 @article{al-rubaei_merriman_hunt_viklander_marsalek_blecken_2017, title={Survey of the Operational Status of 25 Swedish Municipal Stormwater Management Ponds}, volume={143}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001203}, DOI={10.1061/(ASCE)EE.1943-7870.0001203}, abstractNote={AbstractDuring the past 50 years, wet stormwater ponds have been constructed to reduce negative environmental impacts of urban stormwater discharges on receiving aquatic environments. However, in m...}, number={6}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Al-Rubaei, Ahmed Mohammed and Merriman, Laura S. and Hunt, William F., III and Viklander, Maria and Marsalek, Jiri and Blecken, Godecke-Tobias}, year={2017}, month={Jun}, pages={05017001} }
 @article{winston_al-rubaei_blecken_hunt_2016, title={A Simple Infiltration Test for Determination of Permeable Pavement Maintenance Needs}, volume={142}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001121}, DOI={10.1061/(ASCE)EE.1943-7870.0001121}, abstractNote={AbstractPermeable pavements allow stormwater to pass through the pavement surface, filtering out sediment and debris; over time, regular preventative maintenance will be needed to maintain the pavement surface infiltration rate (IR). IR testing is commonly used to determine maintenance needs and frequencies. ASTM standard methods may be used to measure permeable pavement IR; however, these tests can take hours to complete and require infiltrometers not readily available to maintenance contractors. A simple infiltration test (SIT) has been devised which (1) is conducted using easily acquired materials, (2) has a larger surface area (i.e., more representative of average pavement conditions), and (3) requires, on average, 72% less time to conduct than the ASTM test. ASTM and SIT methods were compared by conducting a total of 873 IR tests at the same locations on 12 permeable pavements in North Carolina, Ohio, and Sweden. Results showed that (1) a segmented linear relationship related SIT and ASTM-measured IR...}, number={10}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Winston, Ryan J. and Al-Rubaei, Ahmed M. and Blecken, Godecke T. and Hunt, William F.}, year={2016}, month={Oct}, pages={06016005} }
 @article{fassman-beck_hunt_berghage_carpenter_kurtz_stovin_wadzuk_2016, title={Curve Number and Runoff Coefficients for Extensive Living Roofs}, volume={21}, ISSN={1084-0699 1943-5584}, url={http://dx.doi.org/10.1061/(ASCE)HE.1943-5584.0001318}, DOI={10.1061/(ASCE)HE.1943-5584.0001318}, abstractNote={AbstractLiving roofs are a green infrastructure (GI)/low-impact development (LID) stormwater control measure (SCM) increasingly drawing worldwide attention. Despite substantial performance evidence in the literature, the lack of a curve number (CN) or volumetric runoff coefficient (Cv) to apply to prescribed methodologies for planning and regulatory submissions may be perceived as a barrier for implementation. Paired rainfall–runoff data were analyzed for up to 21 living roofs with varying configurations and in different climates from studies identified in the literature and previously-unpublished data. Frequency analysis of empirical performance evidence from 14 living roofs indicates that meaningful runoff is not generated from the majority of small rainfall events. Where planning requires the use of the CN method, a step function is suggested: (1) runoff volume=0 for design rainfall events up to 20–30 mm, if appropriate moisture storage capacity is provided by the substrate; (2) runoff volume is determ...}, number={3}, journal={Journal of Hydrologic Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Fassman-Beck, Elizabeth and Hunt, William and Berghage, Robert and Carpenter, Donald and Kurtz, Timothy and Stovin, Virginia and Wadzuk, Bridget}, year={2016}, month={Mar}, pages={04015073} }
 @article{merriman_hunt_bass_2016, title={Development/ripening of ecosystems services in the first two growing seasons of a regional-scale constructed stormwater wetland on the coast of North Carolina}, volume={94}, ISSN={["1872-6992"]}, DOI={10.1016/j.ecoleng.2016.05.065}, abstractNote={A well-functioning constructed stormwater wetland (CSW) will provide many ecosystem services. However, there has not been an effort to monitor and evaluate these services as a CSW develops in the first years after construction – the ‘ripening’ period. In this study, ecosystem services development was assessed during the first two growing seasons of a CSW located on the coast of North Carolina. The CSW research site was a regional-scale stormwater project with two different flow regimes: event and base flow. The full potential of some ecosystem services of this CSW were realized immediately such as volume reduction, TSS and NO2,3 treatment. Others were fully developed after the 1st growing season, e.g. TAN, ON, TN, and TP treatment. Mostly, ripening of the CSW was complete, as areal C densities exceeded median C densities observed in other stormwater wetlands, and vegetation biodiversity measurements aligned with other stormwater wetlands in North Carolina, just one year after construction. The establishment of vegetation was deemed the most important design goal during this vital period, as vegetation is interlinked with other services: evapotranspiration, water quality improvement, and C input to the soil.}, journal={ECOLOGICAL ENGINEERING}, author={Merriman, L. S. and Hunt, W. F. and Bass, K. L.}, year={2016}, month={Sep}, pages={393–405} }
 @article{manka_hathaway_tirpak_he_hunt_2016, title={Driving forces of effluent nutrient variability in field scale bioretention}, volume={94}, ISSN={["1872-6992"]}, DOI={10.1016/j.ecoleng.2016.06.024}, abstractNote={Nutrient exports from urbanized watersheds have been identified as a major contributor to surface water degradation worldwide. As efforts to implement stormwater treatment controls, such as bioretention, become increasingly common, understanding how the functionality of these systems varies based on environmental conditions is critical. Quantifying this variability and its causes will aid in developing more robust models and watershed restoration plans which incorporate the uncertainty of bioretention function. This study investigated effluent nutrient concentrations from ten bioretention areas in North Carolina, USA. Nitrogen species were found to have higher variability than phosphorus species, with changes in effluent concentrations being significantly influenced by environmental conditions. In particular, effluent concentrations of total nitrogen (TN) and nitrate (NO3-N) were strongly correlated to antecedent rainfall depth and temperature. As antecedent rainfall depth increased, NO3-N and TN concentrations decreased. These trends have been noted in other laboratory-based studies and are logical based on the influence of dry conditions on microbial communities. Increases in ambient temperature were shown to increase effluent TN and NO3-N concentrations in conventionally drained systems. However, a negative correlation was found between temperature and effluent NO3-N concentrations in systems with an internal water storage (IWS) layer, suggesting increased denitrifying microbe activity. These results show that variability in effluent nutrient concentrations can be explained by environmental conditions, and that the effects of these conditions may differ based on system design.}, journal={ECOLOGICAL ENGINEERING}, author={Manka, B. N. and Hathaway, J. M. and Tirpak, R. A. and He, Q. and Hunt, W. F.}, year={2016}, month={Sep}, pages={622–628} }
 @article{gee_hunt_2016, title={Enhancing Stormwater Management Benefits of Rainwater Harvesting via Innovative Technologies}, volume={142}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001108}, DOI={10.1061/(ASCE)EE.1943-7870.0001108}, abstractNote={AbstractRainwater harvesting (RWH) systems provide the dual, but often opposing, benefits of acting as alternate water supply sources and providing detention/retention of roof runoff that would otherwise become stormwater runoff. A major challenge that exists when using a RWH system to simultaneously accomplish stormwater and water-conservation benefits in nonarid regions is that these systems are often underutilized, thus remaining full a large portion of the time. For a system to mitigate stormwater runoff, however, there must be sufficient room available in the tank to store a runoff event. Two novel approaches were implemented to improve the ability of RWH systems to serve as both water-conservation practices and stormwater-management practices: an active release technology and a passive release technology. Two locations in Craven County, North Carolina, had RWH systems installed to capture roof runoff and store it for nonpotable uses. One system was equipped with the passive release mechanism, which ...}, number={8}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Gee, K. D. and Hunt, W. F.}, year={2016}, month={Aug}, pages={04016039} }
 @article{johnson_hunt_2016, title={Evaluating the spatial distribution of pollutants and associated maintenance requirements in an 11 year-old bioretention cell in urban Charlotte, NC}, volume={184}, ISSN={["1095-8630"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84994339362&partnerID=MN8TOARS}, DOI={10.1016/j.jenvman.2016.10.009}, abstractNote={Bioretention cells (BRCs) are an increasingly popular Stormwater Control Measure used to mitigate the hydrologic and water quality impacts of urbanization. Previous BRC research has demonstrated a strong capacity for pollutant removal; however, long-term sequestration of pollutants within soil media can elevate concentrations to levels fostering environmental and human health risks. Soil media samples were collected from an 11 year-old BRC in Charlotte, NC, and analyzed for the accumulation and spatial distribution of zinc, copper, and phosphorus. Pollutant distribution varied significantly with respect to depth and ordinate distance from the BRC inlet. Zinc concentrations (0.9–228.6 mg kg−1 soil) exceeded environmental thresholds and phosphorus concentrations (5.1–173.3 mg kg−1 soil) increased from initial levels by a factor of seven; however, notable accumulation was restricted to the BRC forebay. Maximum zinc and copper concentrations in soil media did not exceed 1% of mandatory cleanup levels and with regular maintenance of the forebay, the effective life of BRC media should exceed the life of the developments they treat.}, journal={JOURNAL OF ENVIRONMENTAL MANAGEMENT}, publisher={Elsevier BV}, author={Johnson, Jeffrey P. and Hunt, William F.}, year={2016}, month={Dec}, pages={363–370} }
 @article{winston_al-rubaei_blecken_viklander_hunt_2016, title={Maintenance measures for preservation and recovery of permeable pavement surface infiltration rate - The effects of street sweeping, vacuum cleaning, high pressure washing, and milling}, volume={169}, DOI={10.1016/j.jenvman.2015.12.026}, abstractNote={The surface infiltration rates (SIR) of permeable pavements decline with time as sediment and debris clog pore spaces. Effective maintenance techniques are needed to ensure the hydraulic functionality and water quality benefits of this stormwater control. Eight different small-scale and full-scale maintenance techniques aimed at recovering pavement permeability were evaluated at ten different permeable pavement sites in the USA and Sweden. Maintenance techniques included manual removal of the upper 2 cm of fill material, mechanical street sweeping, regenerative-air street sweeping, vacuum street sweeping, hand-held vacuuming, high pressure washing, and milling of porous asphalt. The removal of the upper 2 cm of clogging material did not significantly improve the SIR of concrete grid paves (CGP) and permeable interlocking concrete pavers (PICP) due to the inclusion of fines in the joint and bedding stone during construction, suggesting routine maintenance cannot overcome improper construction. For porous asphalt maintenance, industrial hand-held vacuum cleaning, pressure washing, and milling were increasingly successful at recovering the SIR. Milling to a depth of 2.5 cm nearly restored the SIR for a 21-year old porous asphalt pavement to like-new conditions. For PICP, street sweepers employing suction were shown to be preferable to mechanical sweepers; additionally, maintenance efforts may become more intensive over time to maintain a threshold SIR, as maintenance was not 100% effective at removing clogging material.}, journal={Journal of Environmental Management}, author={Winston, R. J. and Al-Rubaei, A. M. and Blecken, G. T. and Viklander, M. and Hunt, W. F.}, year={2016}, pages={132–144} }
 @article{winston_dorsey_hunt_2016, title={Quantifying volume reduction and peak flow mitigation for three bioretention cells in clay soils in northeast Ohio}, volume={553}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2016.02.081}, abstractNote={Green infrastructure aims to restore watershed hydrologic function by more closely mimicking pre-development groundwater recharge and evapotranspiration (ET). Bioretention has become a popular stormwater control due to its ability to reduce runoff volume through these pathways. Three bioretention cells constructed in low permeability soils in northeast Ohio were monitored for non-winter quantification of inflow, drainage, ET, and exfiltration. The inclusion of an internal water storage (IWS) zone allowed the three cells to reduce runoff by 59%, 42%, and 36% over the monitoring period, in spite of the tight underlying soils. The exfiltration rate and the IWS zone thickness were the primary determinants of volume reduction performance. Post-construction measured drawdown rates were higher than pre-construction soil vertical hydraulic conductivity tests in all cases, due to lateral exfiltration from the IWS zones and ET, which are not typically accounted for in pre-construction soil testing. The minimum rainfall depths required to produce outflow for the three cells were 5.5, 7.4, and 13.8mm. During events with 1-year design rainfall intensities, peak flow reduction varied from 24 to 96%, with the best mitigation during events where peak rainfall rate occurred before the centroid of the rainfall volume, when adequate bowl storage was available to limit overflow.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Winston, Ryan J. and Dorsey, Jay D. and Hunt, William F.}, year={2016}, month={May}, pages={83–95} }
 @article{morse_walter_osmond_hunt_2016, title={Roadside soils show low plant available zinc and copper concentrations}, volume={209}, ISSN={["1873-6424"]}, DOI={10.1016/j.envpol.2015.11.011}, abstractNote={Vehicle combustion and component wear are a major source of metal contamination in the environment, which could be especially concerning where road ditches are actively farmed. The objective of this study was to assess how site variables, namely age, traffic (vehicles day−1), and percent carbon (%C) affect metal accumulation in roadside soils. A soil chronosequence was established with sites ranging from 3 to 37 years old and bioavailable, or mobile, concentrations of Zinc (Zn) and Copper (Cu) were measured along major highways in North Carolina using a Mehlich III extraction. Mobile Zn and Cu concentrations were low overall, and when results were scaled via literature values to “total metal”, the results were still generally lower than previous roadside studies. This could indicate farming on lands near roads would pose a low plant toxicity risk. Zinc and Cu were not correlated with annual average traffic count, but were positively correlated with lifetime traffic load (the product of site age and traffic count). This study shows an often overlooked variable, site age, should be included when considering roadside pollution accumulation. Zinc and Cu were more strongly associated with %C, than traffic load. Because vehicle combustion is also a carbon source, it is not obvious whether the metals and carbon are simply co-accumulating or whether the soil carbon in roadside soils may facilitate previously overlooked roles in sequestering metals on-site.}, journal={ENVIRONMENTAL POLLUTION}, author={Morse, Natalie and Walter, M. Todd and Osmond, Deanna and Hunt, William}, year={2016}, month={Feb}, pages={30–37} }
 @article{winston_davidson-bennett_buccier_hunt_2016, title={Seasonal Variability in Stormwater Quality Treatment of Permeable Pavements Situated Over Heavy Clay and in a Cold Climate}, volume={227}, ISSN={["1573-2932"]}, DOI={10.1007/s11270-016-2839-6}, number={5}, journal={WATER AIR AND SOIL POLLUTION}, author={Winston, Ryan J. and Davidson-Bennett, Keely M. and Buccier, Kristen M. and Hunt, William F.}, year={2016}, month={May} }
 @article{hathaway_winston_brown_hunt_mccarthy_2016, title={Temperature dynamics of stormwater runoff in Australia and the USA}, volume={559}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2016.03.155}, abstractNote={Thermal pollution of surface waters by urban stormwater runoff is an often overlooked by-product of urbanization. Elevated stream temperatures due to an influx of stormwater runoff can be detrimental to stream biota, in particular for cold water systems. However, few studies have examined temperature trends throughout storm events to determine how these thermal inputs are temporally distributed. In this study, six diverse catchments in two continents are evaluated for thermal dynamics. Summary statistics from the data showed larger catchments have lower maximum runoff temperatures, minimum runoff temperatures, and temperature variability. This reinforces the understanding that subsurface drainage infrastructure in urban catchments acts to moderate runoff temperatures. The catchments were also evaluated for the presence of a thermal first flush using two methodologies. Results showed the lack of a first flush under traditional assessment methodologies across all six catchments, supporting the results from a limited number of studies in literature. However, the time to peak temperature was not always coincident with the time to peak flow, highlighting the variability of thermal load over time. When a new first flush methodology was applied, significant differences in temperature were noted with increasing runoff depth for five of the six sites. This study is the first to identify a runoff temperature first flush, and highlights the need to carefully consider the appropriate methodology for such analyses.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Hathaway, J. M. and Winston, R. J. and Brown, R. A. and Hunt, W. F. and McCarthy, D. T.}, year={2016}, month={Jul}, pages={141–150} }
 @inproceedings{newman_hunt_2016, title={The Restoration of James Brindley’s Last Canal and the Serious Threat from 21st Century Transport Infrastructure Developments}, ISBN={9780784479841}, url={http://dx.doi.org/10.1061/9780784479841.014}, DOI={10.1061/9780784479841.014}, abstractNote={James Brindley is widely recognised as a pioneer of the British canal system. His last project was the proposal to provide a waterway from Chesterfield to the River Trent from where the local iron, coal and lead could be transported to their principal markets in London. By 1769 a route had been surveyed charting a course which indicated a move away from the earlier “contour following canals” to the much more ambitious routes taken by later British canals. This included the longest canal tunnel in Britain and extensive use of multi-flight locks. In 1907, the tunnel collapsed due to mining subsidence, never to be reopened. The inland section fell into disrepair and was in-filled in places. This paper reports the efforts of volunteer bodies to reopen the canal, including a proposed ambitious engineering task to by-pass the collapsed tunnel. With funding streams identified, an announcement about a new high-speed rail line which will impact on the canal has brought funding streams to a halt. This paper will also highlight how the opportunity to restore to use, one of the most important heritage projects in the U.K., may have been lost but will also show how history shows that rail developments need not bring us to the end of the line.}, booktitle={World Environmental and Water Resources Congress 2016}, publisher={American Society of Civil Engineers}, author={Newman, Alan P. and Hunt, William F.}, year={2016}, month={May}, pages={124–133} }
 @article{carmen_hunt_anderson_2016, title={Volume Reduction Provided by Eight Residential Disconnected Downspouts in Durham, North Carolina}, volume={142}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001107}, DOI={10.1061/(ASCE)EE.1943-7870.0001107}, abstractNote={AbstractOne major concern of increased development is the proportion of directly connected impervious areas (DCIA) in urbanized watersheds. A cost-efficient opportunity to treat stormwater within existing residential and small-scale commercial developments is to disconnect roof gutter downspouts and direct impervious surface runoff over lawns. Four paired residential downspout disconnection sites in Durham, North Carolina, were studied to quantify volume and peak flow reduction. Hydrologic data were collected from January 22, 2013, to October 8, 2013. For each site, the performance of disconnected downspouts discharging water over existing lawn was compared for three varying factors: slope of lawn, length of run over lawn, and proportion of contributing roof area to receiving lawn area. Data were analyzed from approximately 60 storm events. Performance was evaluated by calculating volume reduction with and without the direct rainfall on the lawn, resulting in cumulative runoff volume reduction ranges of 5...}, number={10}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Carmen, N. B. and Hunt, William F. and Anderson, A. R.}, year={2016}, month={Oct}, pages={05016002} }
 @inproceedings{carey_page_shew_hunt, iii_2015, title={A Collaborative Approach to Voluntary Watershed Restoration in Coastal North Carolina}, ISBN={9780784479025}, url={http://dx.doi.org/10.1061/9780784479025.041}, DOI={10.1061/9780784479025.041}, abstractNote={Watershed Coordinator, City of Wilmington, Stormwater Services, 209 Coleman Drive, PO Box 1810, Wilmington, NC 28412. Email:erin.carey@wilmingtonnc.gov Extension Associate, Dept. of Biological and Agricultural Engineering, North Carolina State Univ., Campus Box 7625, Raleigh, NC 27695. Email: jlpage3@ncsu.edu Lecturer in Geology, Dept. of Geology and Geography, University of North Carolina at Wilmington, 601 South College Road, Wilmington, NC 28403. Email: shewr@uncw.edu Professor and Extension Specialist, Dept. of Biological and Agricultural Engineering, North Carolina State Univ., Campus Box 7625, Raleigh, NC 27695. Email: bill_hunt@ncsu.edu}, booktitle={International Low Impact Development Conference 2015}, publisher={American Society of Civil Engineers}, author={Carey, Erin S. and Page, Jonathan L. and Shew, Roger D. and Hunt, III, William F.}, year={2015}, month={Jan} }
 @inproceedings{carey_page_shew_hunt_2015, title={A collaborative approach to voluntary watershed restoration in coastal North Carolina}, booktitle={LID: It Works In All Climates and Soils}, author={Carey, E. S. and Page, J. L. and Shew, R. D. and Hunt, W. F.}, year={2015}, pages={404–410} }
 @article{winston_lauffer_narayanaswamy_mcdaniel_lipscomb_nice_hunt_2015, title={Comparing Bridge Deck Runoff and Stormwater Control Measure Quality in North Carolina}, volume={141}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0000864}, DOI={10.1061/(ASCE)EE.1943-7870.0000864}, abstractNote={AbstractBridge deck runoff sometimes directly discharges through deck drains to water bodies. As such, the runoff is usually not treated; however, recent pressures have led Departments of Transportation to install closed pipe drainage systems beneath bridges to deliver stormwater to a stormwater control measure (SCM). This can be costly both in terms of up-front and long-term maintenance capital. This study compared bridge runoff concentrations of nutrients, sediment, and heavy metals to effluent concentrations from six commonly used SCMs. Runoff quality samples from 15 bridges in North Carolina were collected and compared to those from 41 different SCMs across North Carolina. The SCMs examined in this study were permeable friction course (PFC) overlays, wet retention ponds (WP), bioretention cells (BRC), vegetated filter strips (VFS), constructed stormwater wetlands (CSW), and grassed swales (GS). Bridge deck runoff concentrations were not statistically different from SCM effluent concentrations for tota...}, number={1}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Winston, Ryan J. and Lauffer, Matthew S. and Narayanaswamy, Karthik and McDaniel, Andrew H. and Lipscomb, Brian S. and Nice, Alex J. and Hunt, William F.}, year={2015}, month={Jan}, pages={04014045} }
 @article{wilson_hunt_winston_smith_2015, title={Comparison of Runoff Quality and Quantity from a Commercial Low-Impact and Conventional Development in Raleigh, North Carolina}, volume={141}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0000842}, DOI={10.1061/(ASCE)EE.1943-7870.0000842}, abstractNote={AbstractUrbanization and its associated increased impervious footprint lead to stream impairment through erosion, flooding, and augmented pollutant loads. Low-impact development (LID) focuses on di...}, number={2}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Wilson, C. E. and Hunt, W. F. and Winston, R. J. and Smith, P.}, year={2015}, month={Feb}, pages={05014005} }
 @article{borne_fassman-beck_winston_hunt_tanner_2015, title={Implementation and Maintenance of Floating Treatment Wetlands for Urban Stormwater Management}, volume={141}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0000959}, DOI={10.1061/(ASCE)EE.1943-7870.0000959}, abstractNote={AbstractThe floating treatment wetland (FTW) is an innovative hydroponic device which can be installed on the surface of a stormwater retention pond to improve its pollutant removal efficiency. Limited full-scale experiments have been published, and no design or maintenance guidelines have been developed to date to promote their use. This paper presents implementation and maintenance considerations developed based on the monitoring of three full-scale ponds retrofitted with FTWs. Results suggest that the size and relative surface cover of the FTW, the relative root depth, and the capability of the plants to tolerate periodic anaerobic conditions are crucial factors to promote good removal across a spectrum of pollutants. Special attention to the location and anchorage of the FTW are thought to promote good performance and facilitate FTW maintenance. While zinc and copper sediment concentrations were unlikely to cause undue aquatic impacts after 2 years of operation, more frequent sediment removal will be ...}, number={11}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Borne, Karine E. and Fassman-Beck, Elizabeth A. and Winston, Ryan J. and Hunt, William F. and Tanner, Chris C.}, year={2015}, month={Nov}, pages={04015030} }
 @article{smolek_hunt_grabow_2015, title={Influence of Drawdown Period on Overflow Volume and Pollutant Treatment for Detention-Based Stormwater Control Measures in Raleigh, North Carolina}, volume={1}, ISSN={2379-6111 2379-6111}, url={http://dx.doi.org/10.1061/JSWBAY.0000798}, DOI={10.1061/JSWBAY.0000798}, abstractNote={AbstractThe drawdown rate of detention-based stormwater control measures (SCMs) influences both the treatment capability of the device and the volume of runoff that becomes untreated overflow. Currently, hydrologic design goals set by the North Carolina Department of Environmental and Natural Resources and other mid-Atlantic U.S. state agencies (e.g., those in Maryland, Virginia, and Pennsylvania) require stormwater practices to treat, e.g., 90% of stormwater runoff (or similar). This equates to a 10% overflow volume, defined as the percentage of inflow volume that bypasses the SCM and therefore receives minimal treatment. For detention-based SCMs, this design goal is met by sizing the outlet to release runoff generated from the water quality event (in North Carolina, either 25 or 38 mm) over a required minimum period of 2 days. Previous studies have not shown whether rainfall patterns in North Carolina and other east coast United States states justify a 2-day drawdown rate of the water quality event to l...}, number={2}, journal={Journal of Sustainable Water in the Built Environment}, publisher={American Society of Civil Engineers (ASCE)}, author={Smolek, Alessandra P. and Hunt, William F., III and Grabow, Garry L.}, year={2015}, month={May}, pages={05015001} }
 @article{page_winston_mayes_perrin_hunt_2015, title={Retrofitting Residential Streets with Stormwater Control Measures over Sandy Soils for Water Quality Improvement at the Catchment Scale}, volume={141}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0000898}, abstractNote={AbstractImpervious cover (IC) has been shown to increase runoff volumes, peak discharges, and pollutant loads to streams, which can lead to degraded water quality and biological integrity. Stormwater control measures (SCMs) have been developed to mitigate the hydrologic and water quality impacts of urban areas and IC. This paired watershed study evaluated the impacts of multiple SCM retrofits on water quality at a catchment scale in a 0.53 ha urban residential drainage area. In February 2012, an in-street bioretention cell (BRC) retrofit, four permeable pavement parking stalls, and a tree filter device were installed to treat residential street runoff in Wilmington, North Carolina. In the retrofitted catchment, 94% of the directly connected impervious area (DCIA) and 91% of the total drainage area were retrofitted for water quality treatment. Underlying soils in the study area were sand. After the SCM retrofits were constructed, concentrations of total Kjeldahl nitrogen (TKN), total phosphorous (TP), tota...}, number={4}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Page, Jonathan L. and Winston, Ryan J. and Mayes, Dave B. and Perrin, Christy A. and Hunt, William F., III}, year={2015}, month={Apr} }
 @article{page_winston_mayes_perrin_hunt_2015, title={Retrofitting with innovative stormwater control measures: Hydrologic mitigation of impervious cover in the municipal right-of-way}, volume={527}, ISSN={["1879-2707"]}, DOI={10.1016/j.jhydrol.2015.04.046}, abstractNote={Impervious Cover (IC) has been shown to increase runoff volumes, peak discharges and pollutant loads to streams, which leads to degraded water quality and biological integrity. Stormwater Control Measures (SCMs) have been developed to mitigate the hydrologic and water quality impacts of urban areas and IC. This paired watershed study evaluated the impacts of SCM retrofits on hydrology for a small urban drainage area. In February 2012, a bioretention cell (BRC) street retrofit, four permeable pavement parking stalls and a tree filter device were installed to control and treat residential street runoff in Wilmington, North Carolina, USA. In the SCM-Retrofit catchment, 52% of the directly connected impervious area (DCIA) and 69% of the total drainage area was retrofitted for potential hydrologic mitigation. Underlying soils in the study area were urban sands. Peak discharge significantly decreased by 28%, while lag times in the catchment remained unchanged. Runoff depth significantly decreased by 52%. When compared to the control catchment, runoff depths in the SCM-Retrofit catchment were significantly less for events with low hourly rainfall intensities (<2.7 mm/h), but significantly greater for events with high intensities (>7.4 mm/h). During post-retrofit monitoring, runoff thresholds in the SCM-Retrofit and control catchments were 5.2 mm and 3.5 mm, respectively. The SCM-Retrofit runoff coefficient decreased from 0.38 to 0.18 and was substantially less than other runoff coefficients reported in the literature for conventional residential development. This study illustrated how a limited number of SCM retrofits installed within the public right-of-way can mitigate some of the hydrologic impacts of existing residential development.}, journal={JOURNAL OF HYDROLOGY}, author={Page, Jonathan L. and Winston, Ryan J. and Mayes, Dave B. and Perrin, Christy and Hunt, William F., III}, year={2015}, month={Aug}, pages={923–932} }
 @misc{fletcher_shuster_hunt_ashley_butler_arthur_trowsdale_barraud_semadeni-davies_bertrand-krajewski_et al._2015, title={SUDS, LID, BMPs, WSUD and more - The evolution and application of terminology surrounding urban drainage}, volume={12}, ISSN={["1744-9006"]}, DOI={10.1080/1573062x.2014.916314}, abstractNote={The management of urban stormwater has become increasingly complex over recent decades. Consequently, terminology describing the principles and practices of urban drainage has become increasingly diverse, increasing the potential for confusion and miscommunication. This paper documents the history, scope, application and underlying principles of terms used in urban drainage and provides recommendations for clear communication of these principles. Terminology evolves locally and thus has an important role in establishing awareness and credibility of new approaches and contains nuanced understandings of the principles that are applied locally to address specific problems. Despite the understandable desire to have a ‘uniform set of terminology’, such a concept is flawed, ignoring the fact that terms reflect locally shared understanding. The local development of terminology thus has an important role in advancing the profession, but authors should facilitate communication between disciplines and between regions of the world, by being explicit and accurate in their application.}, number={7}, journal={URBAN WATER JOURNAL}, author={Fletcher, Tim D. and Shuster, William and Hunt, William F. and Ashley, Richard and Butler, David and Arthur, Scott and Trowsdale, Sam and Barraud, Sylvie and Semadeni-Davies, Annette and Bertrand-Krajewski, Jean-Luc and et al.}, year={2015}, month={Oct}, pages={525–542} }
 @article{page_winston_hunt_2015, title={Soils beneath suspended pavements: An opportunity for stormwater control and treatment}, volume={82}, ISSN={["1872-6992"]}, DOI={10.1016/j.ecoleng.2015.04.060}, abstractNote={Trees provide air quality, water quality and aesthetic benefits to urban areas. However, urban soils are frequently compacted to meet the structural stability requirements of pavements and buildings. Suspended pavement systems create an uncompacted soil volume beneath pavements in built environments to provide suitable conditions for tree root growth and structural stability for pavements. Another potential use of the soil–root matrix beneath a suspended pavement includes stormwater management. Two suspended pavement systems were constructed in Wilmington, North Carolina, USA, and runoff was routed through the root–soil matrix for detention and treatment. The two retrofits each contained 21.2 m3 of soil volume with a crape myrtle (Lagerstroemia indica x fauriei) and were nearly identical. An impermeable geomembrane isolated the water quality impacts of the system and an internal water storage (IWS) layer promoted NO2,3-N removal through denitrification. At one retrofit, 80% of runoff over the yearlong monitoring period was treated. For storms that did not generate bypass, significant mitigation of peak discharge (QP) was observed (62%). Pollutant concentrations of TKN, NO2,3-N, TAN, TN, O-PO43−, TP, TSS, Cu, Pb and Zn all decreased significantly at both retrofit sites. Effluent NO2,3-N concentrations between the retrofit sites were not significantly different despite varying organic matter content and a substantial difference in influent NO2,3-N concentrations. Effluent concentrations of TSS, Cu, and Zn were not statistically different between the sites, indicating consistent treatment of particulate and particulate-bound pollutants within the systems. This proof-of-concept study illustrates that the soil–root matrix beneath a suspended pavement system can be used as a stormwater control measure (SCM) to concomitantly achieve water quality, pavement stability and urban forestry goals.}, journal={ECOLOGICAL ENGINEERING}, author={Page, Jonathan L. and Winston, Ryan J. and Hunt, William F., III}, year={2015}, month={Sep}, pages={40–48} }
 @inproceedings{anderson_smolek_hunt_2015, title={Stormwater Treatment Performance of a Permeable Pavement-Biofiltration System and a Stand-Alone Biofiltration Unit in North Carolina}, ISBN={9780784479025}, url={http://dx.doi.org/10.1061/9780784479025.022}, DOI={10.1061/9780784479025.022}, abstractNote={A BioPave® treatment train was retrofitted in an existing parking lot in Fayetteville, North Carolina, USA. The BioPave® treatment train comprises of a permeable pavement and Filterra® devices in series. Additionally, a stand-alone Filterra® biofiltration device was installed on the same site to evaluate its performance at treating pollutants of concern in North Carolina and elsewhere. The purpose of this study is to gain insight into the water quality treatment capabilities of a PICP—flow-through filter treatment train and to evaluate the standalone device’s hydrologic and water quality performance. Automated, flowproportional water quality samplers were installed to collect samples at multiple locations at each SCM. It was seen that the Filterra® standalone device had sediment concentration reductions above 95% for both TSS and SSC. For nutrients, the Filterra reduced the percent total phosphorus and total nitrogen concentrations by a median of 62 and 33%, respectively. Overall the system treated the one-inch design storm before significant overflow occurred, and showed a similar watershed characteristics to pre-developed conditions. The BioPave TM system removed sediment, nitrogen, and phosphorus well despite having some moderate to severe clogging issues throughout the study, resulting in load reductions of 69, 84, and 72% by mass for nitrogen, phosphorus, and sediment, primarily through the mechanism of infiltration into the sandy loam underlying soils beneath the pavers.}, booktitle={International Low Impact Development Conference 2015}, publisher={American Society of Civil Engineers}, author={Anderson, A. R. and Smolek, A. P. and Hunt, W. F.}, year={2015}, month={Jan}, pages={216–226} }
 @article{blecken_hunt_al-rubaei_viklander_lord_2015, title={Stormwater control measure (SCM) maintenance considerations to ensure designed functionality}, volume={14}, ISSN={1573-062X 1744-9006}, url={http://dx.doi.org/10.1080/1573062X.2015.1111913}, DOI={10.1080/1573062X.2015.1111913}, abstractNote={Abstract Great investment is made in the design and installation of stormwater control measures (SCMs). Substantial research investment, too, is made to optimise the performance of SCMs. However, once installed, SCMs often suffer from lack of maintenance or even outright neglect. Key maintenance needs for wet ponds, constructed stormwater wetlands, bioretention, infiltration practices, permeable pavement, swales, and rainwater harvesting systems are reviewed with many tasks, such as the cleaning of pre-treatment areas and the preservation of infiltration surfaces, being common maintenance themes among SCMs. Consequences of lacking maintenance are illustrated (mainly insufficient function or failure). Probable reasons for neglect include insufficient communication, unclear responsibilities, lack of knowledge, financial barriers, and decentralised measures. In future designs and research, maintenance (and lack thereof) should be considered. Assessing the performance of SCMs conservatively and including safety factors may prevent consequences of under-maintenance; and requiring regular inspection may help to enforce sufficient maintenance.}, number={3}, journal={Urban Water Journal}, publisher={Informa UK Limited}, author={Blecken, Godecke-Tobias and Hunt, William F., III and Al-Rubaei, Ahmed Mohammed and Viklander, Maria and Lord, William G.}, year={2015}, month={Nov}, pages={278–290} }
 @article{hathaway_hunt_mccarthy_2015, title={Variability of Intra-event Statistics for Multiple Fecal Indicator Bacteria in Urban Stormwater}, volume={29}, ISSN={["1573-1650"]}, DOI={10.1007/s11269-015-1020-0}, number={10}, journal={WATER RESOURCES MANAGEMENT}, author={Hathaway, J. M. and Hunt, W. F. and McCarthy, D. T.}, year={2015}, month={Aug}, pages={3635–3649} }
 @article{wilson_hunt_winston_smith_2014, title={Assessment of a rainwater harvesting system for pollutant mitigation at a commercial location in Raleigh, NC, USA}, volume={14}, ISSN={["1606-9749"]}, DOI={10.2166/ws.2013.200}, abstractNote={Low Impact Development (LID) and Water Sensitive Urban Design have as one of their tenets the use of rainwater harvesting (RWH) systems to provide water for use on site. Historically implemented in arid or semi-arid regions, RWH has recently surged in popularity in more humid regions, such as the southeastern USA, due to increased interest in water conservation during severe drought conditions. An LID commercial site in Raleigh, NC, incorporated RWH with other stormwater control measures to mitigate runoff quantity and improve runoff quality. A 57,900-liter RWH tank used for landscape irrigation was monitored to determine influent and effluent water quality. Samples were analyzed for total nitrogen, total phosphorus, total Kjeldahl nitrogen (TKN), total ammoniacal nitrogen (TAN), nitrite-nitrate (NOX), orthophosphate (Ortho-P) and total suspended solids (TSS). Low concentrations were observed for all pollutants monitored; for example, influent and effluent TP concentrations were 0.02 and 0.03 mg/L, respectively. Statistical testing showed significant increases in TAN and organic nitrogen (ON) concentrations by 33 and 38%, respectively, from inflow to outflow. NOX and TSS concentrations decreased significantly by 23 and 55%, respectively. Concentrations of all other pollutants were not significantly different between the inflow and outflow. Influent concentrations to the RWH tank were less than previously published rainfall pollutant concentrations, indicating potentially irreducible concentrations onsite. While a single case study, this RWH system appears to offer some pollutant mitigation, especially for TSS.}, number={2}, journal={WATER SCIENCE AND TECHNOLOGY-WATER SUPPLY}, author={Wilson, Corinne E. and Hunt, William F., III and Winston, Ryan J. and Smith, Patrick}, year={2014}, pages={283–290} }
 @article{hathaway_brown_fu_hunt_2014, title={Bioretention function under climate change scenarios in North Carolina, USA}, volume={519}, ISSN={["1879-2707"]}, DOI={10.1016/j.jhydrol.2014.07.037}, abstractNote={The effect of climate change on stormwater controls is largely unknown. Evaluating such effects is important for understanding how well resiliency can be built into urban watersheds by implementing these systems. Bioretention areas with varied media depths, in situ soil types, drainage configurations, and surface infiltration capabilities have previously been monitored, modelled, and calibrated using the continuous simulation model, DRAINMOD. In this study, data from downscaled climate projections for 2055 through 2058 were utilized in these models to evaluate changes in system hydrologic function under two climate change scenarios (RCP 4.5 and 8.5). The results were compared to those generated using a “Base” scenario of observed data from 2001 to 2004. The results showed a modest change in the overall water balance of the system. In particular, the frequency and magnitude of overflow from the systems substantially increased under the climate change scenarios. As this represents an increase in the amount of uncontrolled, untreated runoff from the contributing watersheds, it is of particular concern. Further modelling showed that between 9.0 and 31.0 cm of additional storage would be required under the climate change scenarios to restrict annual overflow to that of the base scenario. Bioretention surface storage volume and infiltration rate appeared important in determining a system’s ability to cope with increased yearly rainfall and higher rainfall magnitudes. As climate change effects vary based on location, similar studies should be performed in other locations to determine localized effects on stormwater controls.}, journal={JOURNAL OF HYDROLOGY}, author={Hathaway, J. M. and Brown, R. A. and Fu, J. S. and Hunt, W. F.}, year={2014}, month={Nov}, pages={503–511} }
 @inproceedings{winston_lauffer_narayanaswamy_mcdaniel_lipscomb_nice_hunt_2014, title={Comparing Stormwater Control Measure Effluent Quality with Road Runoff Management in Mind}, ISBN={9780784413548}, url={http://dx.doi.org/10.1061/9780784413548.014}, DOI={10.1061/9780784413548.014}, abstractNote={Road runoff has been identified as a source of urban stormwater pollution. Bridges represent a special case, as they often directly discharge through deck drains near or into open water. As such, the runoff is usually not treated with a swale and filter strip, as it would be in the typical highway cross-section; recently, departments of transportation have begun using closed pipe drainage systems to deliver stormwater to a stormwater control measure (SCM) for treatment. This is a costly retrofit both in terms of up-front and long-term maintenance capital. Bridge runoff quality (in terms of nutrients, sediment, and heavy metals) was contrasted against effluent concentrations from six commonly used SCMs. Runoff quality samples from 41 different SCMs were collected and compared with those from 15 different bridges across the three ecoregions of North Carolina (mountains, piedmont, and coastal plain). SCMs examined in this study were permeable friction course (PFC) overlays, wet retention ponds (WP), bioretention cells (BRC), vegetated filter strips (VFS), constructed stormwater wetlands (CSW), and grassed swales (GS). Bridge runoff concentrations were statistically compared with SCM effluent concentrations; all SCMs were unable to produce statistically lower total nitrogen effluent concentrations than those from bridge runoff. For total phosphorus, all SCMs were shown to reduce bridge runoff concentrations, though only PFC, BRC, and WP did so significantly. For total suspended solids (TSS), median effluent concentrations from the SCMs were significantly and substantially lower than those draining from bridges (>15 mg/L in all cases). Similar results were observed for copper, lead, and zinc; BRC, GS, and CSW were able to lower total metals concentrations significantly when compared with bridge runoff. Dissolved metal concentrations appeared difficult to reduce with current SCM technology. These results suggest that for certain pollutants, treatment of bridge runoff may yield improvement. However, the appropriateness of installing SCMs to treat bridge deck runoff must account for increased cost of closed pipe drainage systems beneath bridges and limited space in the right of way and weighed against the relative ease of retrofitting stormwater treatment infrastructure into other transportation corridors.}, booktitle={World Environmental and Water Resources Congress 2014}, publisher={American Society of Civil Engineers}, author={Winston, Ryan J. and Lauffer, Matthew S. and Narayanaswamy, Karthik and McDaniel, Andrew H. and Lipscomb, Brian S. and Nice, Alex J. and Hunt, William F.}, year={2014}, month={May} }
 @inproceedings{baird_hunt, iii_winston_2014, title={Evaluating the Hydrologic and Water Quality Performance of Infiltrating Wet Retention Ponds}, ISBN={9780784413548}, url={http://dx.doi.org/10.1061/9780784413548.017}, DOI={10.1061/9780784413548.017}, abstractNote={Wet retention basins have typically been designed to capture and slowly release stormwater to mitigate peak flow rates and settle out particulate-bound pollutants. However, in locations with Hydrologic Soil Group A soils, such as much of Fayetteville, North Carolina, many wet retention basins may provide additional stormwater benefits through infiltration and evaporation. These benefits are not currently captured in the State of North Carolina's crediting system, wherein wet ponds are thought of as flow-through systems. Engineering designers in the area must line these basins with bentonite clay to prevent infiltration and to comply with the state water quality requirements. Intuitively, a device that infiltrates and reduces effluent volume while still reducing the peak flow rate of infrequent return interval storms could be a desirable practice. However, currently data are lacking to assess how well these infiltrating ponds function and no guidance exists as to how much pollutant removal credit to award. Two infiltrating wet retention basins were monitored in Fayetteville to assess the hydrologic and water quality performance. Results show both ponds have substantial volume reductions. Both ponds had a volume reduction of 100% during October. Median peak flow reductions were 99.2% and 99.7%. Despite minimal data, both ponds clearly are effective in removing TSS with median percent reductions of 67% and 84%. Median percent reductions for TN were 20% and 38%, and those for TP were 15% and 63%. However, due to the substantial volume reductions, the performance of each pond should be assessed based on loading and not solely on concentration reductions. Due to the substantial volume reductions, peak flow rate reductions, and potential for nutrient loading reduction, these devices could be an acceptable stormwater control measure.}, booktitle={World Environmental and Water Resources Congress 2014}, publisher={American Society of Civil Engineers}, author={Baird, Joshua and Hunt, III, William and Winston, Ryan}, year={2014}, month={May} }
 @inproceedings{carmen_hunt_anderson_2014, title={Evaluating the Performance of Disconnected Downspouts on Existing and Amended Lawns as a Stormwater Control Measure}, ISBN={9780784413548}, url={http://dx.doi.org/10.1061/9780784413548.015}, DOI={10.1061/9780784413548.015}, abstractNote={Current trends in population growth and subsequent increased development are requiring engineers and designers to think of innovative solutions that maximize the effective use of land. An additional byproduct of increased development is increased impervious surface and therefore greater volume of stormwater runoff. One unrealized opportunity to treat stormwater within existing residential and small-scale commercial developments is to disconnect downspouts and release impervious surface runoff over lawns. Past research has been done on directing highway and parking lot runoff to vegetated filter strips for the purpose of infiltration and pollutant removal; however, no peer-reviewed study has researched whether directing residential rooftop runoff to release over lawn can substantially reduce runoff volumes though infiltration and thus reduce loading on downstream natural systems. This research compiles data from four paired residential downspout disconnection studies in Durham, North Carolina. The data collection spans two study periods. In the initial study period (January – October 2013), each site was designed to compare the performance of disconnected downspouts releasing water over existing lawn for one of three varying conditions: slope of lawn, length of lawn, or contributing roof area. Analysis of data from the initial study period shows 59 – 99% total volume reduction. The second study period (January – September 2014) will analyze the impact of tilling and soil amendments on the performance of downspout}, booktitle={World Environmental and Water Resources Congress 2014}, publisher={American Society of Civil Engineers}, author={Carmen, N. B. and Hunt, W. F. and Anderson, A. R.}, year={2014}, month={May} }
 @article{hathaway_krometis_hunt_2014, title={Exploring Seasonality in
            Escherichia coli
            and Fecal Coliform Ratios in Urban Watersheds}, volume={140}, ISSN={0733-9437 1943-4774}, url={http://dx.doi.org/10.1061/(ASCE)IR.1943-4774.0000700}, DOI={10.1061/(ASCE)IR.1943-4774.0000700}, abstractNote={AbstractAs regulators in the United States develop plans to mitigate microbial pollution via the design of total maximum daily load (TMDL) plans, historical data sets are often used to establish existing conditions for watersheds. Due to the revision of guidance recommending Escherichia coli (E. coli) as the preferred target indicator species in surface-water quality-monitoring programs, historical fecal-coliform concentration data are often used to estimate E. coli concentrations and loadings. Data from Raleigh and Durham, North Carolina, suggest the ratio of E. coli to fecal coliform (EC/FC) varies significantly by season throughout the year (p<0.05). These seasonal differences are not accounted for in most translator equations, which assume a single linear relationship between E. coli and fecal coliform regardless of season. These observations imply that seasonal translator equations may more accurately reflect the relationship between fecal coliforms and E. coli, and would thus result in the developme...}, number={4}, journal={Journal of Irrigation and Drainage Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Hathaway, J. M. and Krometis, L. H. and Hunt, W. F.}, year={2014}, month={Apr}, pages={04014003} }
 @article{debusk_hunt_2014, title={Impact of rainwater harvesting systems on nutrient and sediment concentrations in roof runoff}, volume={14}, ISSN={["1606-9749"]}, DOI={10.2166/ws.2013.191}, abstractNote={Rainwater harvesting (RWH) systems have the unique ability to contribute to stormwater management goals via mitigation of runoff volumes and peak flow rates. Additionally, collecting and storing runoff via RWH systems can potentially provide water quality benefits due to physical and chemical processes that occur within the storage tank. This study quantified the water quality improvement provided by storing rooftop runoff via RWH systems at four sites in Raleigh, North Carolina, USA. Roof runoff and extraction spigot samples were analyzed for total suspended solids (TSS), nitrogen species and total phosphorus. Roof concentrations were significantly greater than spigot concentrations for all constituents except TSS, indicating the ability of RWH systems to significantly lower nutrient concentrations of incoming roof runoff. Lack of significant TSS reduction was likely attributable to low, ‘irreducible’ concentrations of TSS in the roof runoff. The use of additional filtration components prior to the extraction spigot could aid in lowering spigot TSS concentrations. The findings presented herein contend that stormwater benefits associated with RWH are not only limited to hydrologic mitigation, but also include reductions in concentrations of nitrogen and phosphorus species. Thus, it is recommended that pollutant removal credit be assigned to these systems when used as stormwater control measures.}, number={2}, journal={WATER SCIENCE AND TECHNOLOGY-WATER SUPPLY}, author={DeBusk, Kathy M. and Hunt, William F., III}, year={2014}, pages={220–229} }
 @article{merriman_hunt_2014, title={Maintenance versus Maturation: Constructed Storm-Water Wetland’s Fifth-Year Water Quality and Hydrologic Assessment}, volume={140}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0000861}, DOI={10.1061/(ASCE)EE.1943-7870.0000861}, abstractNote={AbstractConstructed storm-water wetlands (CSWs) have become popular storm water control measures (SCMs) in low-lying coastal environments, offering a hybrid between larger detention practices (wet ponds) and newer green infrastructure technologies. However, it is relatively rare that CSWs are monitored once the practice has aged 4 years, causing some concern among stakeholders about the long-term performance of CSWs. The specific objective of this research was to investigate the effects that wetland maturation and lack of maintenance have on the ability of a 5-year-old CSW to mitigate hydrology and improve water quality. A CSW was monitored from 2012–2013 that had not been maintained since construction in the spring of 2007. Since then, it has established as a diverse and healthy ecosystem. The monitoring results were compared with the results of a study conducted at the same site for a 1-year period immediately following construction (2007–2008). In 2007–2008, runoff volumes were reduced 54% and peak dis...}, number={10}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Merriman, Laura S. and Hunt, William F., III}, year={2014}, month={Oct}, pages={05014003} }
 @article{wardynski_winston_line_hunt_2014, title={Metrics for assessing thermal performance of stormwater control measures}, volume={71}, ISSN={["1872-6992"]}, DOI={10.1016/j.ecoleng.2014.07.068}, abstractNote={Urban runoff can impact the thermal regime of surface waters and degrade valuable aquatic ecosystems. Some stormwater control measures (SCMs) have been shown to mitigate the effects of thermally-enriched runoff, but previous studies lacked consistency when characterizing the thermal behavior of SCMs. Ecologically-relevant parameters such as maximum outflow temperature, duration of temperatures exceeding thresholds for coldwater species, and thermal load have all been considered in past research. Standard metrics that properly represent the downstream impacts of urban stormwater were needed. This paper evaluated thermal metrics to provide designers and regulators with catchment-scale methods for assessing thermal performance and compliance. It was concluded that multiple metrics must be employed to account for both thermal load and biologically-based reference temperature limits. Metrics for temperature evaluations were broken out by data requirements. When only SCM temperature data are available, event mean temperature estimation appears to be the most rigorous metric. Groundwater temperature may also be employed as a surrogate metric for SCM discharge temperatures if conservative protection of coldwater stream health is desired. When SCM temperature and flow data exist, thermal load reductions should be explored. Efficacy of the low impact development (LID) strategy for temperature mitigation (retaining onsite greater than the 95th percentile storm event) was evaluated using field-collected permeable pavement data. Based on these data, retaining the 95th percentile storm event was determined to be an effective technique for thermal protection of surface waters. However, the most rigorous metrics involve long-term temperature and flow data from local reference streams. The best metric currently available is the uniform continuous above threshold (UCAT) method, in which it is necessary to consider continuous exposure duration when comparing against biological thresholds. These analyses can be tailored to specific species of interest within a targeted ecoregion. Combined with thermal load and mixing analysis in-stream, the UCAT method can provide a real-world estimation of the impacts of development. Additionally, evaluation of mixing zones in-stream should also be employed to adequately assess thermal impacts. However, these methods are the most data intensive. The metrics discussed in this paper can be used to inform new and existing design methodologies for regulating stormwater temperature, duration, and thermal load.}, journal={ECOLOGICAL ENGINEERING}, author={Wardynski, Brad J. and Winston, Ryan J. and Line, Daniel E. and Hunt, William F.}, year={2014}, month={Oct}, pages={551–562} }
 @inproceedings{smolek_hunt_winston_2014, title={Modeling Hydrologic Performance of Permeable Pavement with DRAINMOD in North Carolina and Ohio}, ISBN={9780784413548}, url={http://dx.doi.org/10.1061/9780784413548.003}, DOI={10.1061/9780784413548.003}, abstractNote={Variations in the hydrologic performance of permeable pavement can be due to several factors including gravel storage depth, drainage configuration, surface infiltration rate, and underlying soil type. A long-term hydrologic model is needed to better understand the influence of these factors on surface runoff, drainage, and exfiltration from permeable pavement systems. DRAINMOD is a widely accepted agricultural drainage model that can predict water table level, drainage, infiltration, and evapotranspiration continuously over long records of time. Past research has shown that DRAINMOD can be calibrated to accurately predict the hydrology of bioretention areas. Given that water movement through a permeable pavement cell is similar to a bioretention area, it is hypothesized that the model could also be calibrated to predict the hydrologic response from permeable pavement. Both stormwater control measures (SCMs) employ infiltration as the primary mechanism for peak flow attenuation and exfiltration for volume reduction. Drainage configurations for both SCMs are also analogous to the required DRAINMOD inputs. This study investigates the application of DRAINMOD to predict permeable pavement hydrology for a variety of different drainage configurations and underlying soil types. Three sites in North Carolina and one site in Ohio were monitored for rainfall, drainage outflow, and internal water level for a period of 9 to 12 months. The four sites have varying drainage configurations and underlying soils to represent a wide variety of permeable pavement applications. The model was calibrated for a period of 4 to 6 months at each site and validated for an additional 4 to 6 months. Results comparing the field-monitored and modeled volumes of drainage, surface runoff, and exfiltration/ET will be presented for each site. Preliminary results at the Boone, NC, site indicate success in predicting drainage volumes, with Nash-Sutcliffe efficiencies of 0.97 during the calibration period and 0.85 during the validation period. How the DRAINMOD outputs can be extended to predict the annual average water balance for varying drainage configurations and underlying soil types will also be discussed.}, booktitle={World Environmental and Water Resources Congress 2014}, publisher={American Society of Civil Engineers}, author={Smolek, A. P. and Hunt, W. F. and Winston, R. J.}, year={2014}, month={May} }
 @inproceedings{anderson_smolek_hunt_2014, title={Permeable Pavement and Filterra Performance at an Amtrak Station in North Carolina, USA}, ISBN={9780784413548}, url={http://dx.doi.org/10.1061/9780784413548.018}, DOI={10.1061/9780784413548.018}, abstractNote={Two proprietary stormwater treatment systems were continuously monitored for water quality and quantity at an Amtrak Station in Fayetteville, NC. A standalone Filterra® biofiltration unit and a permeable pavement-Filterra® treatment train (Filterra BioPave®) were evaluated for nitrogen and phosphorus parameters, sediment, metals, particle size, pH, and specific gravity, with further data to be collected until spring of 2014. Despite the fact that this study is currently ongoing, and final data is not available, the Filterra devices, on their own, appear to remove sediment and sediment-bound nitrogen and phosphorus well with percent removals of at least 45% for all solid species. Dissolved species were not removed as well, with some instances of export. One explanation for this behavior may be the lack of vegetation in the watershed. It is a mostly barren old asphalt lot, which sheds many particulate particles into the Filterra, but may not contribute plant matter, which would be a source of typical dissolved phosphorus and nitrogen. As a result of this possible lack of nutrients, the system did not "see" high loads entering. This would contribute to a lower percent removal, which is one negative toward the metric's use for stormwater control measures (SCM) accreditation. While more data are still coming in, the BioPave system appears to be highly efficient in removing stormwater entirely, almost completely due to the infiltration ability of the permeable pavement system. Due to complications with BioPave Filterra effluent, it cannot yet be concluded how well the Filterra portion of this treatment train further cleans the water, but some preliminary evidence indicates that the double treatment of stormwater—both by a permeable pavement application, and a Filterra filtration system—would utilize different low impact development (LID) processes to clean stormwater further. The results of this field study may be used by Virginia and North Carolina to gain official acceptance in the individual states' best management practices manual with nutrient removals accredited to the systems if appropriate.}, booktitle={World Environmental and Water Resources Congress 2014}, publisher={American Society of Civil Engineers}, author={Anderson, A. R. and Smolek, A. P. and Hunt, W. F.}, year={2014}, month={May} }
 @article{hathaway_hunt_guest_mccarthy_2014, title={Residual indicator bacteria in autosampler tubing: a field and laboratory assessment}, volume={69}, ISSN={["1996-9732"]}, DOI={10.2166/wst.2014.035}, abstractNote={Microbial contamination in surface waters has become a worldwide cause for concern. As efforts are made to reduce this contamination, monitoring is integral to documenting and evaluating water quality improvements. Autosamplers are beneficial in such monitoring efforts, as large data sets can be generated with minimized effort. The extent to which autosamplers can be utilized for microbial monitoring is largely unknown due to concerns over contamination. Strict sterilization regimes for components contacting the water being sampled are difficult, and sometimes logistically implausible, when utilizing autosamplers. Field experimentation showed contamination of fecal coliform in autosamplers to be more of a concern than that of Escherichia coli. Further study in a controlled laboratory environment suggested that tubing configuration has a significant effect on residual E. coli concentrations in sampler tubing. The amount of time that passed since the last sample was collected from a given sampler (antecedent dry weather period – DWP) tubing was also a significant factor. At a DWP of 7 days, little to no contamination was found. Thus, simple protocols such as providing positive drainage of tubing between sample events and programming samplers to include rinses will reduce concerns of contamination in autosamplers.}, number={5}, journal={WATER SCIENCE AND TECHNOLOGY}, author={Hathaway, J. M. and Hunt, W. F. and Guest, R. M. and McCarthy, D. T.}, year={2014}, pages={1120–1126} }
 @inproceedings{wilson_hunt_winston_smith_2013, title={A Comparison of Runoff Quality and Quantity from a Urban Commercial Infill Low Impact Development and a Conventional Development}, ISBN={9780784412947}, url={http://dx.doi.org/10.1061/9780784412947.288}, DOI={10.1061/9780784412947.288}, abstractNote={Urbanization and its associated increased impervious footprint lead to stream impairment through erosion, flooding, and augmented pollutant loads. Low Impact Development (LID) focuses on disconnecting impervious areas, increasing infiltration and evapotranspiration, and reusing stormwater on site through the use of stormwater control measures (SCMs). SCMs, such as bioretention, rainwater harvesting, and permeable pavement, can be used independently or in series to mimic pre-development hydrology. In this study, a conventional development (centralized stormwater management) and a nearby infiltration-based LID commercial site in Raleigh, North Carolina, were compared with respect to stormwater quality and quantity. The conventional development (2.76 ha, 61% directly connected impervious area (DCIA)) and the LID (2.53 ha, 84% DCIA) have underlying hydrologic soil group B soils. A dry detention basin, designed to mitigate peak flow rate, was the conventional development SCM. The LID site consisted of a 44,300-liter aboveground cistern used for indoor toilet flushing, two underground cisterns (57,900 liters and 60,600 liters used for landscape irrigation), and an underground detention system, which overflowed into a series of infiltration galleries beneath the parking lot of the shopping center. The LID shopping center was intended to mimic pre-development hydrology from a runoff perspective for the 10-year return period, 24-hour duration storm. For the 50 hydrologic storms monitored, a mean runoff reduction of 98.1% at the LID site, and a 48.9% mean runoff reduction at the conventional site, when normalized by DCIA. The conventional development had a 9x higher peak flow value, on average, than the LID site when normalized by DCIA. Flow-proportional, composite water quality samples were analyzed for total nitrogen (TN), total phosphorus (TP), total Kjeldahl nitrogen (TKN), ammonia (NH3-N), nitrite-nitrate (NO2+3-N), orthophosphate (PO4-3) and total suspended solids (TSS). For the 19 water quality storms sampled, the LID site pollutant loadings for all species studied were less than 9% of pollutant loadings of the conventional site. Results from this innovative combined detention, stormwater reuse, and infiltration LID system will provide space-saving solutions for areas where aboveground SCMs, such as bioretention and constructed stormwater wetlands, are not feasible due to high land costs and constricted spaces.}, booktitle={World Environmental and Water Resources Congress 2013}, publisher={American Society of Civil Engineers}, author={Wilson, C. E. and Hunt, W. F. and Winston, R. J. and Smith, P. K.}, year={2013}, month={May} }
 @article{hunt_2013, title={Advanced rainwater harvesting and stormwater}, volume={20}, ISSN={1871-5532}, url={http://dx.doi.org/10.1016/J.JCHAS.2013.03.407}, DOI={10.1016/J.JCHAS.2013.03.407}, number={3}, journal={Journal of Chemical Health and Safety}, publisher={Elsevier BV}, author={Hunt, William}, year={2013}, month={May}, pages={42} }
 @article{brown_birgand_hunt_2013, title={Analysis of Consecutive Events for Nutrient and Sediment Treatment in Field-Monitored Bioretention Cells}, volume={224}, ISSN={0049-6979 1573-2932}, url={http://dx.doi.org/10.1007/s11270-013-1581-6}, DOI={10.1007/s11270-013-1581-6}, number={6}, journal={Water, Air, & Soil Pollution}, publisher={Springer Science and Business Media LLC}, author={Brown, Robert A. and Birgand, Francois and Hunt, William F.}, year={2013}, month={May} }
 @article{merriman_wilson_winston_hunt_2013, title={Assessing the Importance of Temporary Storage Volume Occupied by Emergent Vegetation in Constructed Storm Water Wetlands}, volume={18}, ISSN={1084-0699 1943-5584}, url={http://dx.doi.org/10.1061/(ASCE)HE.1943-5584.0000713}, DOI={10.1061/(ASCE)HE.1943-5584.0000713}, abstractNote={AbstractVegetation in a constructed storm water wetland (CSW) is essential for nutrient removal and thermal pollution reduction. However, a portion of the storage volume designed to retain the water quality event is occupied by vegetation, which may result in the CSW being undersized from a hydrologic perspective. The fraction of the volume associated with vegetation mass was unknown and designers have been unsure as to (1) how they should account for volume occupied by vegetation and (2) whether this was a significant design issue. Twelve storm water wetlands and one hybrid wet pond in North Carolina were sampled to assess their percent vegetative occupancy by volume. Vegetation was harvested from randomly selected 0.1  m2 grids at the normal pool elevation, and displacement tests were used to calculate the volume added by vegetation at elevations of 30 and 45 cm. Combining these data with observed vegetative cover, a water quality volume factor of safety accounting for vegetative occupancy was calculate...}, number={10}, journal={Journal of Hydrologic Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Merriman, Laura S. and Wilson, Corinne Eileen and Winston, Ryan J. and Hunt, William F.}, year={2013}, month={Oct}, pages={1372–1376} }
 @article{debusk_hunt_wright_2013, title={CHARACTERIZING RAINWATER HARVESTING PERFORMANCE AND DEMONSTRATING STORMWATER MANAGEMENT BENEFITS IN THE HUMID SOUTHEAST USA}, volume={49}, ISSN={["1752-1688"]}, DOI={10.1111/jawr.12096}, abstractNote={Abstract}, number={6}, journal={JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION}, author={DeBusk, K. M. and Hunt, W. F. and Wright, J. D.}, year={2013}, month={Dec}, pages={1398–1411} }
 @article{brown_skaggs_hunt_2013, title={Calibration and validation of DRAINMOD to model bioretention hydrology}, volume={486}, ISSN={0022-1694}, url={http://dx.doi.org/10.1016/J.JHYDROL.2013.02.017}, DOI={10.1016/J.JHYDROL.2013.02.017}, abstractNote={Previous field studies have shown that the hydrologic performance of bioretention cells varies greatly because of factors such as underlying soil type, physiographic region, drainage configuration, surface storage volume, drainage area to bioretention surface area ratio, and media depth. To more accurately describe bioretention hydrologic response, a long-term hydrologic model that generates a water balance is needed. Some current bioretention models lack the ability to perform long-term simulations and others have never been calibrated from field monitored bioretention cells with underdrains. All peer-reviewed models lack the ability to simultaneously perform both of the following functions: (1) model an internal water storage (IWS) zone drainage configuration and (2) account for soil–water content using the soil–water characteristic curve. DRAINMOD, a widely-accepted agricultural drainage model, was used to simulate the hydrologic response of runoff entering a bioretention cell. The concepts of water movement in bioretention cells are very similar to those of agricultural fields with drainage pipes, so many bioretention design specifications corresponded directly to DRAINMOD inputs. Detailed hydrologic measurements were collected from two bioretention field sites in Nashville and Rocky Mount, North Carolina, to calibrate and test the model. Each field site had two sets of bioretention cells with varying media depths, media types, drainage configurations, underlying soil types, and surface storage volumes. After 12 months, one of these characteristics was altered – surface storage volume at Nashville and IWS zone depth at Rocky Mount. At Nashville, during the second year (post-repair period), the Nash–Sutcliffe coefficients for drainage and exfiltration/evapotranspiration (ET) both exceeded 0.8 during the calibration and validation periods. During the first year (pre-repair period), the Nash–Sutcliffe coefficients for drainage, overflow, and exfiltration/ET ranged from 0.6 to 0.9 during both the calibration and validation periods. The bioretention cells at Rocky Mount included an IWS zone. For both the calibration and validation periods, the modeled volume of exfiltration/ET was within 1% and 5% of the estimated volume for the cells with sand (Sand cell) and sandy clay loam (SCL cell) underlying soils, respectively. Nash–Sutcliffe coefficients for the SCL cell during both the calibration and validation periods were 0.92.}, journal={Journal of Hydrology}, publisher={Elsevier BV}, author={Brown, R.A. and Skaggs, R.W. and Hunt, W.F., III}, year={2013}, month={Apr}, pages={430–442} }
 @inproceedings{winston_bouchard_hunt_2013, title={Carbon Sequestration by Roadside Filter Strips and Swales: A Field Study}, ISBN={9780784413197}, url={http://dx.doi.org/10.1061/9780784413197.028}, DOI={10.1061/9780784413197.028}, abstractNote={As legislation continues to focus on greenhouse gas (GHG) and carbon dioxide (CO2) emissions and reductions, the terrestrial biome offers an attractive possibility to sequester carbon. Currently, the terrestrial pool is regarded as a CO2 sink, but scientists are unsure to what extent this trend will continue. Urbanization modifies the existing landscape, and little study has focused on the carbon (C) dynamics of specific urban land uses. In this research, the roadway environment, specifically grassed right of way (ROW), was studied for carbon sequestration potential, an important ecosystem service. Transportation corridors exist worldwide, and vegetated filter strip and swale (VFS/VS), two common stormwater control measures (SCMs), often constitute the grassed right of way adjacent to roadways. Carbon pools within roadway VFS/VS soils of North Carolina were specifically examined in this study. This research was conducted in two North Carolina physiographic regions: the Piedmont (characterized by clay-influenced soils) and the Coastal Plain (predominantly sandy soils). Approximately 700 soil samples were collected in VFS/VSs and wetland swales alongside major highways and analyzed for percent total soil C (% total C) and bulk density, which aided in obtaining the C density. Mean soil C densities were 2.55 ± 0.13 kg C m-2 (mean ± standard error, n=160, 0.2 m depth) in the Piedmont and 4.14 ± 0.15 kg C m-2 (n=160, 0.2 m depth) in the Coastal Plain highway VFS/VSs. Because grasslands were reported to have similar carbon density values, they could be used as a surrogate land use for roadway VFS/VSs if no specific roadside data were available. Using a 37-year soil chronosequence, the carbon sequestration rate using a simple linear regression within Piedmont VFS/VSs was calculated at 0.053 kg C m-2 yr-1. Utilizing segmented linear regression models, the sequestration rate was calculated to be 0.155 kg C m-2 yr-1 for 15 years and 0.099 kg C m-2 yr-1 for the remaining 21.5 years. The roadside grass sequestration rate assumed by the Federal Highway Administration Carbon Sequestration Pilot Program (0.17 kg C m-2 yr-1) overestimates carbon accumulation by a factor of 3 in the linear model, and by a factor of 1.1 to 1.7 with the segmented linear models. Carbon density did not differ between dry and wetland swales, although % total C was significantly greater in wetland swales. Because C density and % total C in swales were not well defined by age, it appeared more appropriate to assess wetland swales and dry swales using a range of carbon values, rather than a rate of carbon sequestration. The mean VS C density was 3.05 ± 0.13 kg C m-2 (n=40, 0.2 m depth), while that for wetland swales was 5.04 ± 0.73 kg C m-2 (n=44, 0.2 m depth). If promoting C sequestration becomes a factor in ROW management, wetland swales would be more desirable than dry swales. While the VFS/VS sequestration rate is comparable to other grassed systems, the estimated 320-480 tons C per lane-mile expelled during roadway construction (Cass and Mukherjee 2011) is marginally offset through terrestrial sequestration in roadside VFS/VSs. Per kilometer of roadway constructed, Piedmont VFS/VSs would offset between 4% and 7% of C emitted during construction, depending on the predictive model of C sequestration rate that was used.}, booktitle={Green Streets, Highways, and Development 2013}, publisher={American Society of Civil Engineers}, author={Winston, R. J. and Bouchard, N. R. and Hunt, W. F.}, year={2013}, month={Nov} }
 @inproceedings{winston_page_hunt_2013, title={Catchment Scale Hydrologic and Water Quality Impacts of Residential Stormwater Street Retrofits in Wilmington, North Carolina}, ISBN={9780784413197}, url={http://dx.doi.org/10.1061/9780784413197.014}, DOI={10.1061/9780784413197.014}, abstractNote={Low impact development (LID) is a design approach that utilizes stormwater control measures (SCMs) to maintain and restore the natural hydrologic regime of an urban watershed through infiltration, runoff treatment at the source, and minimization of impervious surfaces. This paired watershed study evaluated the impacts of LID SCMs on hydrology and water quality at a catchment scale. In February 2012, a pair of bioretention cell (BRC) bumpouts, two permeable pavement parking stalls, and a tree filter device were installed to treat residential street runoff in Wilmington, North Carolina. In the LID-retrofit catchment, SCMs treated 52% of the directly connected impervious area (DCIA) and 69% of the total drainage area for potential mitigation of peak discharge and runoff volume. For water quality improvement, 94% of the DCIA and 91% of the total drainage area was retrofitted. Underlying soils in the study area were Baymeade Urban and Leon Urban sands. Mean peak discharge significantly decreased 28% post-retrofit and lag times in the catchment remained unchanged, while mean runoff depth significantly decreased 52%. When compared with the control catchment, runoff depths in the LID-retrofit catchment were significantly less for storms with low hourly storm intensities ( 7.4 mm/hr). Runoff thresholds in the LID-retrofit and control catchments were 5.2 mm and 3.5 mm, respectively. The LID runoff coefficient significantly decreased by 47% from 0.22 to 0.13 and is substantially less than other runoff coefficients reported for traditional residential development. Post-retrofit concentrations of total Kjeldahl nitrogen (TKN), total phosphorus (TP), total suspended solids (TSS), copper (Cu), lead (Pb), and zinc (Zn) significantly decreased by 62%, 38%, 82%, 55%, 89%, and 76%, respectively. Concentrations of nitrate-nitrite-nitrogen (NO2,3-N) and total ammoniacal nitrogen (TAN) did not change. Mass exports of TKN, TAN, ortho-phosphate (O-PO4-3), TP, TSS, Cu, Pb, and Zn significantly decreased by 78%, 61%, 55%, 73%, 91%, 53%, 88%, and 77%, respectively. NO2,3-N load decreased by 46%, although this was not significant. Most improvements in water quality were due to dramatic decreases of particulate and particulate-bound pollutant loads. This was attributed to first flush retention of runoff by the BRC and permeable pavement that treated 52% of the DCIA and treatment by the tree filter unit that serviced 42% of the DCIA. This study has shown that a limited number of LID SCMs installed within a medium density residential street right-of-way over sandy soils can mitigate some hydrologic and water quality impacts of existing development.}, booktitle={Green Streets, Highways, and Development 2013}, publisher={American Society of Civil Engineers}, author={Winston, R. J. and Page, J. L. and Hunt, W. F.}, year={2013}, month={Nov} }
 @inproceedings{page_winston_hunt_2013, title={Catchment-Scale Evaluation of the Hydrologic and Water Quality Impacts of Residential Street Retrofits in Wilmington, NC}, ISBN={9780784412947}, url={http://dx.doi.org/10.1061/9780784412947.013}, DOI={10.1061/9780784412947.013}, abstractNote={Many urban watersheds suffer from degraded water quality caused by stormwater runoff from rooftops, parking lots, streets and other impervious surfaces. Low Impact Development (LID) is a design approach that utilizes stormwater control measures (SCMs) to maintain and restore the natural hydrologic features of an urban watershed through infiltration, runoff treatment at the source, and minimization of impervious surfaces. Limited peer-reviewed literature is available on impacts of multiple LID SCMs at a catchment or watershed-scale. A paired watershed study with calibration and treatment monitoring periods has been designed to evaluate the hydrologic and water quality impacts of residential street SCMs at a catchment-scale in Wilmington, North Carolina. Calibration monitoring of the control (0.35 ha) and retrofit (0.53 ha) catchments was completed from May 2011 to October 2011 (9 water quality samples, 14 rainfall events). In February 2012 bioretention bumpouts, permeable pavement parking stalls, and a tree filter device were installed in the retrofit catchment. Treatment monitoring commenced in June 2012 and will continue through February 2013 (10 water quality samples, 15 rainfall events through November 2012). Water quality, peak discharge and flow volume are being recorded at the catchment outlets (existing catch basins). Water quality samples will be analyzed for TSS, TKN, NH4-N, NO2-3-N, TP, Ortho-P, Cu, Pb and Zn. Preliminary results indicate a 14% reduction in mean runoff volume. TSS, TN and TP mass loads at the retrofit outlet decreased by 83%, 49% and 63%, respectively during treatment monitoring. Preliminary water quality and runoff volume results are promising and results from this project will help refine street retrofit design standards to meet runoff volume reduction and water quality goals.}, booktitle={World Environmental and Water Resources Congress 2013}, publisher={American Society of Civil Engineers}, author={Page, J. L. and Winston, R. J. and Hunt, W. F.}, year={2013}, month={May} }
 @article{cizek_hunt_2013, title={Defining predevelopment hydrology to mimic predevelopment water quality in stormwater control measures (SCMs)}, volume={57}, ISSN={["1872-6992"]}, DOI={10.1016/j.ecoleng.2013.04.016}, abstractNote={As part of Low Impact Development, stormwater control measures (SCMs) are expected to mimic pre-development hydrology. This generally results in a comparison between outflow volumes discharged from SCMs and a target condition annual runoff. Such a simplistic evaluation overlooks multiple pathways of water present in target watersheds and SCMs, namely shallow interflow and groundwater surge. This discussion suggests a more refined means of evaluating cognate conditions for SCMs in terms of hydrology and effluent water quality by discretizing SCM discharge into three pathways: runoff, shallow interflow, and groundwater surge. Preliminary evidence using deuterium isotopes from bioretention outflow supports this concept, and future research routes are suggested.}, journal={ECOLOGICAL ENGINEERING}, author={Cizek, Adrienne R. and Hunt, William F.}, year={2013}, month={Aug}, pages={40–45} }
 @article{winston_hunt_kennedy_merriman_chandler_brown_2013, title={Evaluation of floating treatment wetlands as retrofits to existing stormwater retention ponds}, volume={54}, ISSN={0925-8574}, url={http://dx.doi.org/10.1016/J.ECOLENG.2013.01.023}, DOI={10.1016/J.ECOLENG.2013.01.023}, abstractNote={Thousands of existing wet retention ponds have been built across the United States, primarily for the mitigation of peak flow and removal of sediment. These systems struggle to mitigate soluble nutrient loads from urban watersheds. A simple retrofit for improvement of pond performance for nitrogen and phosphorus removal could become popular. Floating treatment wetlands (FTWs), one such retrofit, are a hydroponic system that provides a growing medium for hydrophytic vegetation, which obtain nutrients from the stormwater pond. Installation of FTWs does not require earth moving, eliminates the need for additional land to be dedicated to treatment, and does not detract from the required storage volume for wet ponds (because they float). To test whether FTWs reduce nutrients and sediment, two ponds in Durham, NC, were monitored pre- and post-FTW installation. At least 16 events were collected from each pond during both monitoring periods. The distinguishing characteristic between the two ponds post-retrofit was the fraction of pond surface covered by FTWs; the DOT pond and Museum ponds had 9% and 18%, respectively, of their surface area covered by FTWs. A very small fraction of N and P was taken up by wetland plants, with less than 2% and 0.2%, respectively, of plant biomass as N and P. Temperature measurements at three depths below FTWs and at the same depths in open water showed no significant difference in mean daily temperatures, suggesting little shading benefit from FTWs. The two ponds produced effluent temperatures that exceeded trout health thresholds. Both the pre- and post-FTW retrofit ponds performed well from a pollutant removal perspective. One pond had extremely low total nitrogen (TN) effluent concentrations (0.41 mg/L and 0.43 mg/L) during both pre- and post-FTW retrofit periods, respectively. Floating treatment wetlands tended to improve pollutant capture within both ponds, but not always significantly. Mean effluent concentrations of TN were reduced at the DOT pond from 1.05 mg/L to 0.61 mg/L from pre- to post-retrofit. Mean total phosphorus (TP) effluent concentrations were reduced at both wet ponds from pre- to post-retrofit [0.17 mg/L to 0.12 mg/L (DOT pond) and 0.11 mg/L to 0.05 mg/L (Museum pond)]. The post-retrofit effluent concentrations were similar to those observed for bioretention cells and constructed stormwater wetlands in North Carolina. The DOT pond showed no significant differences between pre- and post-retrofit effluent concentrations for all nine analytes. The Museum pond had a statistically significant improvement post-retrofit (when compared to the pre-retrofit period) for both TP and total suspended solids (TSS). Wetland plant root length was measured to be approximately 0.75 m, which had the benefit of stilling water flow, thereby increasing sedimentation. Results suggested that greater percent coverage of FTWs produced improved pollutant removal.}, journal={Ecological Engineering}, publisher={Elsevier BV}, author={Winston, Ryan J. and Hunt, William F. and Kennedy, Shawn G. and Merriman, Laura S. and Chandler, Jacob and Brown, David}, year={2013}, month={May}, pages={254–265} }
 @article{wardynski_winston_hunt_2013, title={Internal Water Storage Enhances Exfiltration and Thermal Load Reduction from Permeable Pavement in the North Carolina Mountains}, volume={139}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0000626}, abstractNote={AbstractThermally-enriched stormwater runoff can negatively impact coldwater streams and their associated ecosystem services. The introduction of local and federal guidelines specifically targeting urban runoff temperature in the United States and Canada promulgate the use of practices that reduce thermal pollutant load from a catchment. Several stormwater control measures (SCM) have been shown to buffer thermal impacts to waterways by passing water through cooler subsurface media or by reducing overall discharge volume. Permeable pavement exposes stormwater to these mechanisms, which makes it a promising practice for thermal mitigation. A newly constructed permeable interlocking concrete paver (PICP) parking lot was monitored for 1 year in the mountain region of North Carolina to quantify runoff reduction, temperature buffering, and thermal load export. The effects on hydrology caused by internal water storage (IWS) in the pavement profile were also investigated by dividing the 239-m2 lot into three cell...}, number={2}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Wardynski, Brad J. and Winston, Ryan J. and Hunt, William F.}, year={2013}, month={Feb}, pages={187–195} }
 @inproceedings{merriman_hunt_2013, title={Investigating Whether or Not Constructed Stormwater Wetlands Need Maintenance to Sustain Performance and the Effect of Vegetation Occupancy in the Designed Storage Volume}, ISBN={9780784412947}, url={http://dx.doi.org/10.1061/9780784412947.293}, DOI={10.1061/9780784412947.293}, abstractNote={Stormwater wetlands (CSWs) have become one of the more popular SCMs, offering a hybrid between larger detention technologies such as wet ponds and newer green infrastructure technologies. A well-functioning stormwater wetland will be a resilient, diverse ecosystem that includes many plant and animal species. This research looks to investigate whether or not wetlands need regular maintenance to sustain their treatment capacity. The research site is located in River Bend, NC. Flow-weighted samples, rainfall, and hydrologic data are being collected at both the inlet and outlet from April 2012 – April 2013, aiming a minimum of 15 storms space throughout the year. Monitoring of phosphorus deposition consists of taking soil samples and analyzing for Soil Test Phosphorous. These monitoring results will be compared to the results of a study that was conducted at the same site for a one-year period immediately following construction completion. This will allow researchers to see the effects of no maintenance plan (or activity) and time on wetland performance in removing phosphorus and achieving other wetland performance goals. Vegetation in a CSW is essential for nutrient removal and thermal pollution reduction. However, a portion of the storage volume designed to retain the water quality event is occupied by vegetation, which may result in the CSW being undersized from a hydrologic perspective – especially in unmaintained, mature systems. The fraction of the volume associated with vegetation mass was unknown and designers have been unsure as to (1) how they should account for volume occupied by vegetation and (2) whether this was a significant design issue. Twelve stormwater wetlands and one hybrid wet pond in North Carolina were sampled to assess their percent vegetative occupancy by volume. A conservative recommended factor of safety is 1.025. Species-specific factors of safety (FOS) were also calculated; at the 30 cm temporary pool elevation, the Iris (Iris spp.) FOS was highest at 1.020 and the mixed vegetation FOS was lowest at 1.005. When designing a wetland, a more specific FOS may be calculated using a weighted average of the FOS for each species in the planting plan. The outcomes of this research allow designers to account for the volume taken up by emergent wetland vegetation; however, the uncertainty in other factors such as discrepancies between designed and as-built bathymetry probably have a greater impact on the design volume loss when compared to vegetation occupancy (<2%).}, booktitle={World Environmental and Water Resources Congress 2013}, publisher={American Society of Civil Engineers}, author={Merriman, L. S. and Hunt, W. F.}, year={2013}, month={May} }
 @article{price_burchell_hunt_chescheir_2013, title={Long-term study of dune infiltration systems to treat coastal stormwater runoff for fecal bacteria}, volume={52}, ISSN={0925-8574}, url={http://dx.doi.org/10.1016/j.ecoleng.2012.12.008}, DOI={10.1016/j.ecoleng.2012.12.008}, abstractNote={Abstract The discharge of untreated stormwater runoff into recreational waters places swimmers at risk of contracting various illnesses and often results in beach closures or swimming advisories. In an effort to safeguard the public, two experimental Dune Infiltration Systems were installed beneath the sand dunes in Kure Beach, NC. The systems diverted stormwater from two existing beach outfalls, which drained 1.9 ha (4.7 ac) and 3.2 ha (8.0 ac) watersheds, into subsurface chambers for temporary storage and infiltration into the existing sand dunes. A 3-year study examined the long-term performance of the two systems during which 14,584 m 3 (515,046 ft 3 ) of stormwater was diverted into the dunes, with only 438 m 3 (15,457 ft 3 ) bypassing the systems, a nearly 97% capture rating. Enterococci concentrations in stormwater runoff from the watersheds exceeded the state's single sample maximum for Tier I waters (104 MPN/100 mL) in >70% of samples, with geometric means ≥278 MPN/100 mL. Groundwater enterococci concentrations tended to remain below the state limit (≤11% exceedance), with geometric means ≤7 MPN/100 mL. Groundwater monitoring in the control dune, with no direct input of stormwater, had a geometric mean of 5 MPN/100 mL and a 6% exceedance rate. The influences on the local water tables were temporary, as the water table would mound around the systems during infiltration events and dissipate to within pre-storm variations from the control within hours or up to approximately 2 weeks. The Dune Infiltration System appears appropriate for installation in small watersheds (}, journal={Ecological Engineering}, publisher={Elsevier BV}, author={Price, W.D. and Burchell, M.R., II and Hunt, W.F. and Chescheir, G.M.}, year={2013}, month={Mar}, pages={1–11} }
 @inproceedings{winston_hunt_2013, title={Monitoring of Representative Particle Size Distributions and Gross Solids from Roadways and Application to SCM Design}, ISBN={9780784412947}, url={http://dx.doi.org/10.1061/9780784412947.023}, DOI={10.1061/9780784412947.023}, abstractNote={Road runoff treatment is a challenge due to lack of space in the right-of-way. Therefore, it is imperative to understand the quality of runoff from roadways so that efficient stormwater control measures (SCMs) may be designed. In terms of TSS control, the particle size distribution of sediment in the runoff controls the amount of sediment (based on Stokes’ Law) that may be removed through settling in a typical SCM. For best treatment of TSS, the flow depth in vegetated SCMs during the design storm should be limited to the height of the vegetation. Typical roadside stormwater controls (vegetated filter strips and swales) could be designed for water quality by calculating a hydraulic retention time for a particular removal of sediment. In order to do so, an understanding of average particle size distributions (PSDs) was needed for roads across North Carolina (NC). A field monitoring study was conducted during MayNovember 2012 to obtain PSDs from roads in the three ecoregions of NC: mountains, piedmont, and coastal plain. Two sites in the mountains, six in the piedmont, and four in the coastal plain were monitored for TSS concentrations and PSDs for a minimum of six storms apiece. Roadway types were distributed across Interstate highways (6 sites), four lane divided highways (1 site), four lane primary roads (3 sites), and secondary roads (2 sites) to determine the effects that annual average daily traffic have on runoff PSDs. At the Interstate highway sites, two monitoring locations had a permeable friction course (PFC) overlay and one site had a NovaChip overlay, which may modify the expected PSD from a highway. Since nutrients are a concern in NC, nutrient concentrations (TN and TP) were monitored at four sites both in the stormwater and sorbed to the sediment. This will allow for modelling of nutrient removal performance for typical roadway SCMs by estimation of TSS removal from Stokes’ Law. Gross solids (trash, debris, and particles greater than 5 mm in diameter) are often overlooked in loading of nutrients to waterways. Automated stormwater samplers are not able to capture most gross solids, and total maximum daily loads (TMDLs) for these pollutants have been established for some watersheds. Monitoring for gross solids was undertaken at four sites: one in the mountains, two in the piedmont, and one in the coastal plain. Three sites were Interstate highways while one was a divided four lane highway. Dry mass of gross solids as well as nitrogen and phosphorus content were determined in the laboratory. It was determined that gross solids are a substantial portion of the nutrient load, and that they cannot be disregarded in stormwater sampling for nutrient load estimation.}, booktitle={World Environmental and Water Resources Congress 2013}, publisher={American Society of Civil Engineers}, author={Winston, R. J. and Hunt, W. F.}, year={2013}, month={May} }
 @inproceedings{cizek_hunt, iii_2013, title={Partitioning Pre-Development Hydrology in Order to Mimic Pre-Development Water Quality}, ISBN={9780784412947}, url={http://dx.doi.org/10.1061/9780784412947.025}, DOI={10.1061/9780784412947.025}, abstractNote={The primary objective of Low Impact Development (LID) is to maintain pre-development hydrology. This has been achieved by matching the magnitude and duration of pre- and post-development hydrographs. Research on undeveloped watersheds show that stream storm hydrographs are composed of water from one of three pathways: 1) surface runoff, 2) shallow interflow, or 3) groundwater surge. Each of these pathways offers different treatment benefits and is thus essential for optimal nutrient reduction. Stormwater Control Measures (SCMs) providing opportunities for each of these pathways may be better able to mimic pre-development hydrology, particularly in terms of water quality. This research aims to partition the pre-development hydrograph and estimate pre-development water quality. Previous studies on forested watersheds are referenced to establish target hydrograph fractions. Ultimately, this research better defines the goal of pre-development hydrology, while suggesting SCM characteristics to provide opportunities to best mimic pre-development conditions.}, booktitle={World Environmental and Water Resources Congress 2013}, publisher={American Society of Civil Engineers}, author={Cizek, Adrienne R. and Hunt, III, William F.}, year={2013}, month={May} }
 @article{moore_hunt_2013, title={Predicting the carbon footprint of urban stormwater infrastructure}, volume={58}, ISSN={["1872-6992"]}, DOI={10.1016/j.ecoleng.2013.06.021}, abstractNote={Due to increased regulations concerning urban stormwater runoff, stormwater control measures (SCMs) such as bioretention, ponds, and constructed stormwater wetlands, are becoming a more common feature of urban and periurban landscapes. The water quality and hydrologic benefits of SCMs are generally well-documented, and planning tools are available to optimize water quality benefits with economic costs of SCM construction and maintenance. Given rising interest in and potential for regulation of carbon emissions, a planning tool that allows for estimation of carbon emissions associated with SCM construction and maintenance is also a relevant pursuit. The objective of this work was to present a framework by which carbon emissions attributable to SCMs and conveyances could be predicted. This method was then applied to present a comparison of the carbon footprint of eight common SCMs and three stormwater conveyance types. The carbon embodied in construction materials represented a prominent part of the carbon footprint for green roofs, permeable pavement, sand filters, rainwater harvesting systems, and reinforced concrete pipes while material transport and construction dominated that of bioretention systems, ponds, wetlands, level spreader-grassed filter strips and concrete-lined swales. Despite accounting for sequestration by vegetation in these systems, only stormwater wetlands and grassed swales were predicted to store more carbon than what was released through construction and maintenance.}, journal={ECOLOGICAL ENGINEERING}, author={Moore, Trisha L. C. and Hunt, William F.}, year={2013}, month={Sep}, pages={44–51} }
 @article{knight_hunt_winston_2013, title={Side-by-side evaluation of four level spreader-vegetated filter strips and a swale in eastern North Carolina}, volume={68}, ISSN={["0022-4561"]}, DOI={10.2489/jswc.68.1.60}, abstractNote={Level spreader–vegetated filter strips (LS–VFSs) and swales are versatile, low cost stormwater control measures (SCMs). The purpose of this study was to determine the runoff volume and pollutant reductions of four LS–VFSs and a swale in eastern North Carolina (NC). Two vegetated filter strips (VFSs) of 8 m long by 6 m wide (26 ft long by 20 ft wide), two VFSs of 20 m by 6 m (66 ft by 20 ft), and a trapezoidal swale with 3:1 side slopes (0.15 m [0.5 ft] bottom width and 10.4 m [34 ft] long) were constructed. One VFS of each size was amended with a mixture of sand and ViroPhos, a proprietary phosphorus (P) sorptive aggregate. Hydrologic data were collected for rainfall events during the 11-month sampling period. Influent and effluent samples were collected from select rainfall events and analyzed for concentrations of nitrogen (N) and P species, total suspended solids (TSS), cadmium (Cd), copper (Cu), and zinc (Zn). Significant runoff volume reductions averaging 36%, 59%, 42%, 57%, and 23% were found for the small and large unamended VFSs, the small and large amended VFSs, and the swale, respectively (n = 30). In general, concentrations of total nitrogen (TN) and TSS were reduced, while total phosphorus (TP) increased in nearly all treatments. The reductions in TN concentrations were significant in the amended VFSs and the swale, and TN was found to be irreducible at influent concentrations <1 mg L−1 (<1 ppm). TN load reductions in all treatments exceeded the 30% reduction credit assigned by NC, while only the amended VFSs and the swale exceeded the 35% load reduction credit assigned for TP.TN and TP load reductions were not significantly different between the VFSs and the swale. All treatments exceeded 75% TSS load reduction, far exceeding the 40% TSS removal credit that these systems receive in NC. In general, swale and VFS performance was similar in terms of TN and TP load reduction, while the VFSs significantly outperformed the swale in average volume and TSS load reduction.}, number={1}, journal={JOURNAL OF SOIL AND WATER CONSERVATION}, author={Knight, E. M. P. and Hunt, W. F., III and Winston, R. J.}, year={2013}, pages={60–72} }
 @article{merriman_wilson_winston_hunt_2013, title={Sophia title}, volume={18}, number={10}, journal={Journal of Hydrologic Engineering}, author={Merriman, L. S. and Wilson, C. E. and Winston, R. J. and Hunt, W. F.}, year={2013}, pages={1372–1376} }
 @article{bouchard_osmond_winston_hunt_2013, title={The capacity of roadside vegetated filter strips and swales to sequester carbon}, volume={54}, ISSN={["1872-6992"]}, DOI={10.1016/j.ecoleng.2013.01.018}, abstractNote={Carbon capture and storage within vegetation and soil is impacted by changing land uses, which results in either a net source or sink of greenhouse gases (GHGs) to the atmosphere. Transportation corridors are present world-wide, and the vegetated filter strip and vegetated swale (VFS/VS), a common stormwater control measure, often constitutes the right-of-way (ROW) adjacent to roadways. The roadway environment, specifically carbon pools in North Carolina highway ROWs, were studied for carbon sequestration potential, an important ecosystem service. The study was conducted in two North Carolina physiographic regions: the Piedmont (characterized by clay-influenced soils) and the Coastal Plain (predominantly sandy soils). Approximately 700 soil samples were collected in VFS/VSs and wetland swales alongside major highways and analyzed for percent total soil C (% total C) and bulk density to obtain the C density. Mean soil C densities (per unit area) were 2.55 ± 0.13 kg C m−2 (mean ± standard error, n = 160, 0.2 m sample depth) in the Piedmont and 4.14 ± 0.15 kg C m−2 (n = 160, 0.2 m depth) in Coastal Plain highway VFS/VSs. Previous studies on grasslands had similar C density values to those observed in this study; thus, grasslands could be a surrogate land use for highway VFS/VSs. A thirty-seven year soil chronosequence characterized C accumulation in Piedmont VFS/VSs. Carbon density increases showed an association with age in Piedmont VFS/VSs only, which were calculated to reach maximum C density of 3.34 kg C m−2, at age = 21.5 years. Previous studies on grasslands show similar C density and accumulation values to those observed in this study; thus, again grasslands could be a surrogate land use for highway VFS/VSs. Carbon density did not differ between dry or wetland swales, although % total C was significantly greater in wetland swales. The mean VS C density was 3.05 ± 0.13 kg C m−2 (n = 40, 0.2 m depth), while that for wetland swales was 5.04 ± 0.73 kg C m−2 (n = 44, 0.2 m depth). To promote C sequestration in the vegetated ROW, wetland swales appear preferable to dry swales.}, journal={ECOLOGICAL ENGINEERING}, author={Bouchard, Natalie R. and Osmond, Deanna L. and Winston, Ryan J. and Hunt, William F.}, year={2013}, month={May}, pages={227–232} }
 @inproceedings{anderson_hunt_smolek_2013, title={Water Quality and Hydrologic Performance of a Permeable Pavement-Modular Bioretention Treatment Train and a Stormwater Filter Box in Fayetteville, North Carolina}, ISBN={9780784412947}, url={http://dx.doi.org/10.1061/9780784412947.300}, DOI={10.1061/9780784412947.300}, abstractNote={Impervious land cover in urban developments is commonly responsible for degraded water quality and potentially erosive flow rates on downstream water bodies. Many environmental products have recently been developed to satisfy the niche in the market for easy-to-retrofit stormwater practices; however, data on the field performance of these novel stormwater control measures to reduce runoff and improve water quality are limited. Given tight site constraints, retrofitting traditional pavement with pervious pavement provides numerous water quality and hydrologic benefits. This, coupled with other treatment devices as part of a “treatment train”, is becoming a valuable option to reduce a site’s stormwater footprint. A permeable interlocking concrete paver (PICP) system which drains to a 1.2 m by 1.2 m Filterra® bioretention retrofit was installed at an Amtrak parking lot in Fayetteville, North Carolina. With a catchment-to-footprint ratio of 2.5:1, the system is designed to mitigate the 10 year storm, and filter any runoff that does not infiltrate into the sandy-loam subsoil of the PICP. Additionally, a standalone, conventional Filterra® modular bioretention cell was installed on the property to mitigate impervious runoff through a curb throat. Water quality, flow, and ponding level will be monitored at five locations, including: (1) impervious asphalt before the PICP, (2) underdrain leaving the PICP and entering the Filterra, (3) underdrain leaving the Filterra, (4) impervious asphalt before the conventional Filterra, and (5) the underdrain pipe leaving the conventional Filterra. Using flow-paced automatic sampling, the above locations will be monitored for total phosphorus, ortho phosphorus, total soluble phosphorus, nitrate and nitrite, Total Kjeldahl Nitrogen, total ammoniated nitrogen, total nitrogen, particle size distribution, total suspended solids, suspended sediment concentration, specific gravity, copper (Cu), zinc (Zn), and total petroleum hydrocarbons. The goal of this study is to assess the pollutant-removal performance and hydrologic mitigation ability of both proprietary treatment devices, and to use these data to model PICP dynamics. 3042 World Environmental and Water Resources Congress 2013: Showcasing the Future © ASCE 2013}, booktitle={World Environmental and Water Resources Congress 2013}, publisher={American Society of Civil Engineers}, author={Anderson, A. R. and Hunt, W. F. and Smolek, A. P.}, year={2013}, month={May} }
 @article{hathaway_tucker_spooner_hunt_2012, title={A Traditional Analysis of the First Flush Effect for Nutrients in Stormwater Runoff from Two Small Urban Catchments}, volume={223}, ISSN={["1573-2932"]}, DOI={10.1007/s11270-012-1327-x}, number={9}, journal={WATER AIR AND SOIL POLLUTION}, author={Hathaway, J. M. and Tucker, R. S. and Spooner, J. M. and Hunt, W. F.}, year={2012}, month={Nov}, pages={5903–5915} }
 @article{wardynski_hunt_2012, title={Are Bioretention Cells Being Installed Per Design Standards in North Carolina? A Field Study}, volume={138}, ISSN={["0733-9372"]}, DOI={10.1061/(asce)ee.1943-7870.0000575}, abstractNote={AbstractForty-three bioretention cells (BRCs) throughout North Carolina were assessed for maintenance needs, soil media composition, and as-built surface storage volume to determine whether BRCs are typically constructed per their intended design specifications. Visual inspections identified hydric soils and redoximorphic features (indicators of prolonged anaerobic conditions) and quantified the occurrence of issues requiring maintenance. Particle-size distribution and permeability of soil media were measured at multiple locations within each cell, and topographic surveys were performed to calculate as-built surface storage volumes. Field drawdown tests were used to verify permeability measurements and assess overall BRC function. Of the studied cells, 22% contained redoximorphic features in the upper 30 cm, and 53% were in need of maintenance due to one or more factors. Although 71% of assessed cells failed to meet soil media particle-size distribution specifications, 98% of BRCs contained media with ade...}, number={12}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE}, author={Wardynski, Brad J. and Hunt, William F., III}, year={2012}, month={Dec}, pages={1210–1217} }
 @inproceedings{bouchard_hunt_moore_winston_2012, title={Can Roadside Vegetation and Soil Act As a Carbon Sink?}, ISBN={9780784412312}, url={http://dx.doi.org/10.1061/9780784412312.031}, DOI={10.1061/9780784412312.031}, abstractNote={Stormwater Control Measures (SCMs) have long been understood to clean and treat runoff, but these systems may provide additional ecosystem benefits not currently quantified. The main goal of this project was to determine carbon (C) sequestration potential of common roadside SCMs within the Piedmont and Coastal Plain eco-regions of North Carolina. Along highways vegetated filter strips (VFS) and vegetated swales (VS) or wetland swales (WS) work in conjunction to trap sediment bound pollutants associated with runoff from the roadway. The VFS/VS systems work well in the roadside environment since they are linear and easily border the roadway, additionally they require little maintenance. Roadside VFS/VS systems (ranging in age from 1 to 38 years) within two physiographic regions of NC were sampled to evaluate C accumulation within the soil. Based upon ArcGIS analysis, each site was identified and systematically sampled from May to July 2011. Twenty VFS/VS sites were established in the Piedmont and Coastal Plain region, respectively. An additional 20 wetland swale sites were also sampled in the Coastal Plain region, which allows a comparison between the dry swales and the WSs within the Coastal Plain. Age, regional (i.e. Piedmont versus Coastal Plain), position (sampling distance from roadway), depth, and swale characteristics (i.e. WS versus VS) effects upon C accumulation are being examined in this study.}, booktitle={World Environmental and Water Resources Congress 2012}, publisher={American Society of Civil Engineers}, author={Bouchard, N. B. and Hunt, W. F. and Moore, T. L. C. and Winston, R. J.}, year={2012}, month={May} }
 @inproceedings{moore_hunt_2012, title={Developing a Carbon Footprint of Urban Stormwater Infrastructure}, ISBN={9780784412312}, url={http://dx.doi.org/10.1061/9780784412312.089}, DOI={10.1061/9780784412312.089}, abstractNote={Concerns over global climate change have spurred interest in accounting for carbon emissions from human activities. Most of this effort has focused on emissions from vehicles and energy use within buildings. However, relatively little is known about how the urban landscape, and particularly stormwater management, contributes to the carbon footprint of urban areas. The objective of this work was to present a method by which carbon emissions attributable to the construction and maintenance of stormwater control measures (SCMs) and conveyances could be predicted. This method was then applied to present a comparison of the carbon footprint of eight common SCMs and three conveyance practices. The carbon embodied in construction materials represented a prominent part of the carbon footprint for green roofs, permeable pavement, sand filters, rainwater harvesting systems, and reinforced concrete pipes while material transport and construction dominated that of bioretention systems, ponds, wetlands, level spreader-grassed filter strips and concrete-lined swales. Despite accounting for sequestration by vegetation in these systems, only stormwater wetlands and grassed swales were predicted to store more carbon than was released through construction and maintenance.}, booktitle={World Environmental and Water Resources Congress 2012}, publisher={American Society of Civil Engineers}, author={Moore, Trisha L. C. and Hunt, William F.}, year={2012}, month={May} }
 @article{moore_hunt_2012, title={Ecosystem service provision by stormwater wetlands and ponds - A means for evaluation?}, volume={46}, DOI={10.1016/j.watres.2011.11.026}, abstractNote={Stormwater control measures (SCMs) such as constructed stormwater ponds and constructed stormwater wetlands (CSWs) are designed to regulate runoff hydrology and quality. However, these created ecosystems also provide a range of other benefits, or ecosystem services, which are often acknowledged but rarely quantified. In this study, additional ecosystem services, including carbon sequestration, biodiversity, and cultural services, were assessed and compared between 20 ponds and 20 CSWs in North Carolina, USA. Carbon sequestration was estimated through the carbon content of pond and wetland sediments across a gradient of system age. Biodiversity was quantified in terms of the richness and Shannon diversity index of vegetative and aquatic macroinvertebrate communities. Cultural services were qualitatively assessed based on the potential for recreational and educational opportunities at each site. Ponds and wetlands were found to support similar levels of macroinvertebrate diversity, though differences community composition arose between the two habitat types. CSWs demonstrated greater potential to provide carbon sequestration, vegetative diversity, and cultural ecosystem services. This assessment provides an initial framework upon which future assessments of ecosystem service provision by SCMs can build.}, number={20}, journal={Water Research}, author={Moore, T. L. C. and Hunt, W. F.}, year={2012}, pages={6811–6823} }
 @article{jones_hunt_winston_2012, title={Effect of Urban Catchment Composition on Runoff Temperature}, volume={138}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0000577}, abstractNote={AbstractUrban runoff adversely impacts cold-water stream environments due to sporadic fluxes of thermally enriched runoff. This adversely impacts tourism in regions that support trout and salmon streams. Research on storm water control measures (SCMs) has shown that meeting the 21°C trout threshold is not consistently feasible with current SCM technologies. Thus, it is important to consider other factors in storm water temperature management, such as catchment characteristics. Median and maximum runoff temperatures from a shaded parking lot were consistently lower than those from a nearby unshaded lot. This suggests the need to implement a tree canopy cover in trout-sensitive catchments. A light-colored chip seal pavement was compared to a traditional hot-mix asphalt pavement; the light-colored chip seal produced median storm water temperatures that were 1.4°C lower than the standard hot-mix asphalt. It was shown that runoff temperature measurement location is critical when evaluating SCM performance, and...}, number={12}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Jones, Matthew P. and Hunt, William F. and Winston, Ryan J.}, year={2012}, month={Dec}, pages={1231–1236} }
 @article{line_brown_hunt_lord_2012, title={Effectiveness of LID for Commercial Development in North Carolina}, volume={138}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0000515}, DOI={10.1061/(ASCE)EE.1943-7870.0000515}, abstractNote={The purpose of this project was to characterize runoff and pollutant export from three commercial sites: one with no storm water control measures (NoTreat), one with a wet detention basin (WetBasin), and one with low impact development (LID) measures. The sites were located in the Piedmont and Coastal Plain physiographic regions of central North Carolina. Rainfall, runoff, and pollutant concentrations were monitored at each site for more than one year by using automated rain gauges and samplers. The storm event mean concentrations (EMCs) of total kjeldahl nitrogen (TKN), nitrate+nitrite nitrogen (NOx-N), and total phosphorus (TP) in runoff were generally less than corresponding EMCs for many other urban areas in the United States. Also, EMCs were similar to those found for eight parking lots in North Carolina. Storm runoff to rainfall ratio was greatest for the NoTreat site and least for the WetBasin site, which was anticipated because the NoTreat site had no detention/storage and the WetBasin site had the greatest detention/storage. Export of TKN, ammonia nitrogen (NH3-N), TP, and total suspended solids (TSS) was lowest for the LID site, whereas export of NOx-N and TN was lowest for the WetBasin site. Although by no means definitive, the monitoring data indicated that the LID site with its multiple LID measures was more effective at reducing export for most pollutants than the WetBasin site with its wet detention basin.}, number={6}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Line, D. E. and Brown, R. A. and Hunt, W. F. and Lord, W. G.}, year={2012}, month={Jun}, pages={680–688} }
 @inproceedings{wardynski_winston_hunt_2012, title={Enhancement of Exfiltration and Thermal Load Reduction from Permeable Pavement with Internal Water Storage}, ISBN={9780784412312}, url={http://dx.doi.org/10.1061/9780784412312.038}, DOI={10.1061/9780784412312.038}, abstractNote={Stream temperature spikes associated with urban runoff can have negative ecological impacts on coldwater streams. Several local and federal regulations now specifically target urban runoff temperature, which creates a need for practices that reduce thermal export from a catchment. Several stormwater control measures (SCMs) have been shown to buffer thermal impacts to waterways by passing water through cooler subsurface media or by reducing overall runoff volume. Because it performs these functions, permeable pavement is a promising practice for thermal mitigation. A parking lot was constructed with permeable interlocking concrete pavers (PICP) the Mountain region of North Carolina to investigate the thermal behavior of this SCM. The 239-m2 lot was divided into three cells with varying depths and drainage configurations to also test the hydrologic and thermal effects of including internal water storage (IWS) in permeable pavement. After one year of monitoring, results showed substantial stormwater volume reductions from all permeable pavement configurations, with the most pronounced reductions (99.6% and 100%) experienced in the shallow and deep IWS cells, respectively. Consequently, thermal load export from the site was reduced by a comparable amount. Median and maximum stormwater effluent temperatures from the conventionally drained cell (78% runoff reduction) exceeded the critical trout threshold temperature of 21°C, however, outflow only occurred during 8 storm events (out of the 54 recorded). Temperature differentials between the top and bottom the PICP profiles suggest that buffering of extreme runoff temperatures can occur. Additionally, the subsoil interface never reached freezing temperatures during the winter season. These results credit the use of PICP where thermal impact to streams is of concern, particularly with the incorporation of IWS.}, booktitle={World Environmental and Water Resources Congress 2012}, publisher={American Society of Civil Engineers}, author={Wardynski, B. J. and Winston, R. J. and Hunt, W. F.}, year={2012}, month={May} }
 @inproceedings{winston_hunt_lauffer_2012, title={Evaluation of Bridge Deck Runoff and Its Effects on In-Stream Health}, ISBN={9780784412312}, url={http://dx.doi.org/10.1061/9780784412312.041}, DOI={10.1061/9780784412312.041}, abstractNote={Bridges typically drain through scuppers directly to streams or estuaries below, potentially resulting in degradation of surface water quality. The North Carolina General Assembly enacted Session Law 2008-107 in July 2008, which required the N.C. Department of Transportation to study the effects of stormwater runoff from bridges over waterways. The resulting study characterized 15 bridge decks across three ecoregions of N.C. for runoff quality and quantity. Monitoring sites were located across the Piedmont, Coastal Plain, and Mountain ecoregions of NC and had differences in wearing surface, annual average daily traffic, rural vs. urban watershed, bridge deck surface area, and stream drainage areas. The goals included characterizing bridge deck pollutants of concern and determining the effects of bridge deck runoff on in-stream health. Runoff water quality and quantity were measured at 15 bridges, instream water quality and quantity at 4 sites, streambed sediment quality at 30 sites, bioassay tests at 13 sites, and biosurvey tests at 15 sites. Median EMCs for TSS, TN, TP, total petroleum hydrocarbons (TPH), total copper, total lead, and total zinc were 39 mg/L, 0.97 mg/L, 0.17 mg/L, 3.1 mg/L, 9.6 μg/L, 5.3 μg/L, and 66 μg/L, respectively. Twenty-two parameters of concern, those with maximum observed concentrations above the strictest available state or federal threshold, were identified, including: pH, TSS, TN, TP, five total heavy metals, five dissolved heavy metals, and seven semi-volatiles. The best predictor of pollutant concentration was the land-use type of the watershed (urban vs. rural). Pollutant concentrations and loads observed from bridge decks were similar to or less than those from other highway and urban runoff studies. Pollutant loads from the bridge decks for all analytes studied were less than 0.25% of the pollutant load contributed by the whole watershed, since the ratio of bridge deck area to watershed area was always small ( Ceriodaphnia dubia bioassay tests. All samples were tested at 100% concentration, and bridge deck runoff samples also were tested at dilutions of 50%, 25%, 12.5%, and 6.25%. Of 25 bridge deck runoff samples, 3 exhibited toxicity at 100% concentration due to significantly reduced reproduction in the test organism. Potential reasons for this toxicity included elevated conductivity in one sample and low hardness and pH in another sample. No toxicity was observed at lower dilutions of the bridge deck runoff, indicating the potential for toxicity would be attenuated at instream concentrations. Of 20 instream stormflow and baseflow samples, no toxicity was observed. Instream mixing and large catchment area relative to bridge deck footprints (as much as 10 6 larger) resulted in substantial dilution of bridge deck runoff at these sites. Biosurveys (benthic macroinvertebrate sampling) were conducted upstream and downstream of 12 bridges. Samples were obtained using Qual 5 methodology, and bioclassification was determined using the EPT and N.C. biotic index metrics. One study site had a biotic index change large enough to suggest a decline in water quality downstream of the bridge deck. However, bioclassification rating was never different between upstream and downstream sampling areas. When the data were evaluated en masse, runoff concentrations and pollutant loads were similar to those from other urban and transportation runoff studies. Attempts to tie stormwater runoff to reduced in-stream health (sediment quality, benthic health, aquatic toxicity) were unsuccessful; this suggests that bridge deck runoff does not have widespread effects on receiving water quality.}, booktitle={World Environmental and Water Resources Congress 2012}, publisher={American Society of Civil Engineers}, author={Winston, R. J. and Hunt, W. F. and Lauffer, M. S.}, year={2012}, month={May} }
 @inproceedings{winston_hunt_kennedy_2012, title={Evaluation of Floating Wetland Islands As a Retrofit to Existing Stormwater Detention Basins}, ISBN={9780784412312}, url={http://dx.doi.org/10.1061/9780784412312.030}, DOI={10.1061/9780784412312.030}, abstractNote={Since the passage of the Clean Water Act, wet detention ponds have been installed across the United States primarily for peak flow mitigation and sediment reduction. However, there are surprisingly minimal data on water quality benefits of these systems. Additionally, tremendous retrofitting pressure is likely to accompany state of North Carolina-implemented watershed rules associated with the Jordan Lake and Fall Lake reservoirs. Municipalities in these watersheds will be required to meet nutrient load reduction targets, necessitating urban stormwater practice retrofits for existing development. Therefore, it is imperative for many cities in central North Carolina to identify cost effective retrofits. One potential retrofit, floating wetland islands, is particularly attractive because they (1) do not require earth moving, (2) eliminate the need for additional land to be dedicated to treatment, and (3) will not detract from the required storage volume required for wet ponds (because they float). Two wet ponds in Durham, NC, were retrofitted with floating wetland islands. Prior to retrofit, both ponds had little to no vegetation growing inside them. After retrofit, one pond's surface area was comprised of 8% floating wetland islands and the second pond had 19% coverage. The two ponds were monitored in a non-retrofitted state from November 2008 to March 2010. Floating wetland islands were then installed in March-April 2010. After vegetation had established on the islands, monitoring recommenced in July 2010. Area-velocity meters and Manning's equation were used to take flow-proportional, composite water quality samples. Sixteen water quality samples were taken prior to the floating island retrofit, and twelve have been collected thus far post-retrofit. Initial results show that mean effluent concentrations of total nitrogen (TN) were reduced at one pond from 1.05 mg/L to 0.61 mg/L from pre- to post-retrofit. The other pond had relatively low effluent concentrations (0.41 mg/L and 0.43 mg/L) both pre- and post-retrofit. Mean TP effluent concentrations were reduced at both wet ponds from pre- to post-retrofit (0.17 mg/L to 0.12 mg/L and 0.11 mg/L to 0.05 mg/L. Additionally, TSS effluent concentrations at both ponds were modestly lower post-retrofit, presumably due to additional hydraulic resistance provided by the floating islands and their hanging roots, which have been measured to be approximately 0.6 m (2 ft). Initial results show some modest nutrient and sediment removal benefits from the addition of floating islands to stormwater detention ponds. Additional benefits which will be determined in the future include wetland vegetation root mass and potential improvements in benthic macroinvertebrate habitat.}, booktitle={World Environmental and Water Resources Congress 2012}, publisher={American Society of Civil Engineers}, author={Winston, R. J. and Hunt, W. F. and Kennedy, S. G.}, year={2012}, month={May} }
 @article{winston_hunt_kennedy_wright_lauffer_2012, title={Field Evaluation of Storm-Water Control Measures for Highway Runoff Treatment}, volume={138}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0000454}, abstractNote={The thousands of kilometers of highways in North Carolina have the potential to generate large amounts of storm-water runoff. Thus, investigation of storm-water control measures (SCMs) for these somewhat unique linear catchments, where space is limited for SCM implementation, was needed. This study examined the quantity and quality of highway runoff at four sites over a 48-km stretch of Interstate 40 in the coastal plain of North Carolina. The highway had a 4-cm overlay of permeable asphalt, known as permeable friction course (PFC), which influenced the export of sediment-bound pollutants and produced median effluent concentrations of total suspended solids (TSS) of 8  mg/L , 8  mg/L , 9  mg/L , and 17  mg/L at the four sites, well below concentrations observed from standard asphalt highway runoff. Two vegetative filter strips (VFSs), two traditional dry swales, and two wetland swales were also tested for pollutant removal efficacy at the four highway research sites. The filter strips generally produced h...}, number={1}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Winston, Ryan J. and Hunt, William F. and Kennedy, Shawn G. and Wright, Jason D. and Lauffer, Matthew S.}, year={2012}, month={Jan}, pages={101–111} }
 @article{lenhart_hunt_burchell_2012, title={Harvestable Nitrogen Accumulation for Five Storm Water Wetland Plant Species: Trigger for Storm Water Control Measure Maintenance?}, volume={138}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0000550}, DOI={10.1061/(ASCE)EE.1943-7870.0000550}, abstractNote={AbstractAs the use of constructed storm water wetlands to treat storm water runoff becomes more frequent, strategies for maintaining or increasing their pollutant removal over time must be examined. One potential strategy is plant harvesting at the water surface to remove nutrients that would otherwise be deposited back into the wetland during senescence. This technical note presents a first look at this strategy from a storm water management perspective. Vegetation was harvested from two storm water wetlands located in Smithfield and Pactolus, North Carolina, to evaluate the ability of five wetland plant species to sequester nitrogen. Biomass samples were collected from the following species of emergent vegetation: Pontederia cordata (Pickerelweed), Saururus cernuus (Lizard Tail), Scirpus cyperinus (Wool Grass), Sagittaria latifolia (Arrowhead), and Schoenoplectus tabernaemontani (Softstem Bulrush). Samples were collected immediately prior to senescence in September and October 2007 and analyzed for nitr...}, number={9}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Lenhart, H. A. and Hunt, W. F. and Burchell, M. R.}, year={2012}, month={Sep}, pages={972–978} }
 @article{davis_traver_hunt_lee_brown_olszewski_2012, title={Hydrologic Performance of Bioretention Storm-Water Control Measures}, volume={17}, ISSN={["1084-0699"]}, DOI={10.1061/(asce)he.1943-5584.0000467}, abstractNote={The transportation and urban infrastructure relies heavily on impervious surfaces. Unmitigated rainfall runoff from impervious surfaces can lead to a myriad of environmental problems in downgradient areas. To address this issue, novel stormwater control measures (SCMs) are being emphasized and implemented widely to mitigate some of the impacts of impervious surface. Bioretention is a soil/media-based SCM that is often used for this purpose, but current design practices are highly empirical. This study compiles work from three research sites in three states to provide some fundamental underpinnings to bioretention design. Although all sites demonstrate different levels of performance, water volumetric performance trends are common to all. These trends are based on the available storage in the bioretention cell, termed herein as the Bioretention Abstraction Volume (BAV). The BAV is directly related to available media porosity and storage in the surface bowl. A finite capacity to completely store all runoff from smaller events is defined by the BAV. Normalization for this storage provides prediction for volumetric performance. Recommendations for bioretention design are provided.}, number={5}, journal={JOURNAL OF HYDROLOGIC ENGINEERING}, author={Davis, Allen P. and Traver, Robert G. and Hunt, William F. and Lee, Ryan and Brown, Robert A. and Olszewski, Jennifer M.}, year={2012}, month={May}, pages={604–614} }
 @article{brown_hunt_2012, title={Improving bioretention/biofiltration performance with restorative maintenance}, volume={65}, ISSN={["1996-9732"]}, DOI={10.2166/wst.2012.860}, abstractNote={One of the most popular Stormwater Control Measures is bioretention, or biofiltration. Anecdotal evidence suggests that well-designed bioretention cells are often not adequately installed and that maintenance is lacking, leading to less-than-adequate water storage volume and/or surface infiltration rates post-construction. In March 2009, two sets of bioretention cells were repaired by excavating the top 75 mm of fill media, increasing the bioretention surface storage volume by nearly 90% and the infiltration rate by up to a factor of 10. Overflow volume decreased from 35 and 37% in the pre-repair state for two different sets of cells, respectively, to 11 and 12%. Nearly all effluent pollutant loads exiting the post-repair cells were lower than their pre-repair conditions. The bioretention systems employed two different media depths (0.6 and 0.9 m). The deeper media cells discharged less outflow volume than the shallower cells, with 10–11% more runoff volume leaving as exfiltration from the 0.9-m than from the 0.6-m media depth cells. This study showed that maintenance is both critical and beneficial to restore otherwise poorly performing bioretention. Moreover, while deeper media cells did outperform the shallower systems, the improvement in this case was somewhat modest vis-à-vis additional construction costs.}, number={2}, journal={WATER SCIENCE AND TECHNOLOGY}, author={Brown, Robert A. and Hunt, William F.}, year={2012}, pages={361–367} }
 @article{tillinghast_hunt_jennings_d'arconte_2012, title={Increasing Stream Geomorphic Stability Using Storm Water Control Measures in a Densely Urbanized Watershed}, volume={17}, ISSN={["1943-5584"]}, DOI={10.1061/(asce)he.1943-5584.0000577}, abstractNote={This study used previously established unit critical discharges, annual allowable erosional hours, and annual allowable volume of eroded bed-load standards to evaluate two types of storm water control measures (SCMs): low-impact development (LID) practices and a large detention SCM (wet pond). Nine initial scenarios modeled in PC Storm Water Management Model (PCSWMM) incorporated different combinations of wet ponds, green roofs, rainwater harvesting systems, permeable pavement, and rain gardens to determine the best scenario for reducing stream erosion potential within a highly urbanized watershed in Chapel Hill, NC. The best-case scenario to reduce annual erosional hours and eroded bed load within the stream consisted of an aggressive utilization of LID practices in combination with an undersized wet pond. Although this scenario did not meet the annual erosional hour standard for rural reference streams, 0.35 h/ha/year, it did reduce erosional hours and eroded bed-load sediment by factors of 2.4 and 2.5, respectively, improving the existing condition. An alternative wet pond outlet structure that used two elevations of small drawdown orifices was explored to determine if current wet pond design practices could be improved to include stream stability. The new configuration provided a modest reduction in the number of erosional hours, a factor of 1.3, but increased the volume of eroded bed load by a factor of 1.2 when compared with the normal wet pond. However, adding widespread LID practices to the alternative outlet design reduced erosional hours and bed load transport by factors of 1.8 and 1.2, respectively, when compared with the normally configured wet pond. The failure to meet the erosional standards in all scenarios demonstrated the difficulty of requiring highly urbanized watersheds (60% impervious) to meet such strict stream protection measures.}, number={12}, journal={JOURNAL OF HYDROLOGIC ENGINEERING}, author={Tillinghast, E. D. and Hunt, W. F. and Jennings, G. D. and D'Arconte, Patricia}, year={2012}, month={Dec}, pages={1381–1388} }
 @article{hathaway_hunt_2012, title={Indicator Bacteria Performance of Storm Water Control Measures in Wilmington, North Carolina}, volume={138}, ISSN={["1943-4774"]}, DOI={10.1061/(asce)ir.1943-4774.0000378}, abstractNote={Indicator bacteria are a common source of impairment in surface waters in the United States. Urban storm water runoff has been identified as a contributor to elevated indicator bacteria concentrations. Six storm water control measures (SCMs) were monitored in Wilmington, North Carolina, for E. coli and enterococci. Monitored SCMs included two storm water wet ponds, two bioretention cells, and two storm water wetlands. Sandier watersheds in Wilmington potentially lead to differences in SCM performance for indicator bacteria compared to SCMs implemented in clayey watersheds. Results showed E. coli and enterococci concentration reductions between 70 and 98% for the two wet ponds and a bioretention cell with a 60-cm-deep fill media. Other SCMs showed poor removal of indicator bacteria, in some cases negative, with storm water wetlands performing the poorest overall for the three SCM types. Further analysis showed that SCMs with high concentration reductions tended to have geometric mean effluent concentration...}, number={2}, journal={JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING}, author={Hathaway, J. M. and Hunt, W. F.}, year={2012}, month={Feb}, pages={185–197} }
 @article{mccarthy_hathaway_hunt_deletic_2012, title={Intra-event variability of Escherichia coli and total suspended solids in urban stormwater runoff}, volume={46}, ISSN={["0043-1354"]}, DOI={10.1016/j.watres.2012.01.006}, abstractNote={Sediment levels are important for environmental health risk assessments of surface water bodies, while faecal pollution can introduce significant public health risks for users of these systems. Urban stormwater is one of the largest sources of contaminants to surface waters, yet the fate and transport of these contaminants (especially those microbiological) have received little attention in the literature. Stormwater runoff from five urbanized catchments were monitored for pathogen indicator bacteria and total suspended solids in two developed countries. Multiple discrete samples were collected during each storm event, allowing an analysis of intra-event characteristics such as initial concentration, peak concentration, maximum rate of change, and relative confidence interval. The data suggest that a catchment’s area influences pollutant characteristics, as larger catchments have more complex stormwater infrastructure and more variable pollutant sources. The variability of total suspended solids for many characteristics was similar to Escherichia coli, indicating that the variability of E. coli may not be substantially higher than that of other pollutants as initially speculated. Further, variations in E. coli appeared to be more commonly correlated to antecedent climate, while total suspended solids were more highly correlated to rainfall/runoff characteristics. This emphasizes the importance of climate on microbial persistence and die off in urban systems. Discrete intra-event concentrations of total suspended solids and, to a lesser extent E. coli, were correlated to flow, velocity, and rainfall intensity (adjusted by time of concentrations). Concentration changes were found to be best described by adjusted rainfall intensity, as shown by other researchers. This study has resulted in an increased understanding of the magnitude of intra-event variations of total suspended solids and E. coli and what physical and climatic parameters influence these variations.}, number={20}, journal={WATER RESEARCH}, author={McCarthy, D. T. and Hathaway, J. M. and Hunt, W. F. and Deletic, A.}, year={2012}, month={Dec}, pages={6661–6670} }
 @article{brown_line_hunt_2012, title={LID Treatment Train: Pervious Concrete with Subsurface Storage in Series with Bioretention and Care with Seasonal High Water Tables}, volume={138}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0000506}, abstractNote={AbstractTwo infiltrating low-impact development (LID) practices configured in-series, pervious concrete and bioretention (PC-B), were monitored for 17 months to examine the hydrologic and water quality response of this LID treatment train design. For the first LID practice, 0.53 ha of pervious concrete was installed to treat direct rainfall and run-on from 0.36 ha of asphalt parking lot. The pervious concrete was installed over a gravel subsurface storage basin, which was designed to store 25 mm (1 in.) of runoff from the parking lot before draining into the second LID practice, which was a 0.05 ha bioretention cell. The bioretention cell was conventionally drained, had a media depth of 0.5 m (1.6 ft), and was constructed at a location with a high water table. Outflow was only generated in 33 out of 80 monitored events, and over the course of the entire monitoring period, the total outflow volume reduction was 69%. The large outflow reduction subsequently led to high pollutant load reductions for total ni...}, number={6}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Brown, R. A. and Line, D. E. and Hunt, W. F.}, year={2012}, month={Jun}, pages={689–697} }
 @article{hunt_davis_traver_2012, title={Meeting Hydrologic and Water Quality Goals through Targeted Bioretention Design}, volume={138}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0000504}, abstractNote={AbstractBioretention is one of the most commonly used stormwater control measures (SCMs) in North America and Australasia. However, current design is not targeted to regulatory need, often reflecting an outdated understanding of how and why bioretention works. The purpose of this manuscript is to synthesize research to recommend a suite of design standards focused on the purpose of bioretention SCM. Both hydrologic (peak flow mitigation, infiltration, annual hydrology, and stream stability) and water quality [total suspended solids (TSS) and particulates, pathogen-indicator species, metals, hydrocarbons, phosphorus, nitrogen, and temperature] regulatory and stream ecology needs are addressed. Bioretention cells designed to meet a prioritized subset of those measures would be substantially different than cells that are designed for a different subset of needs. Designers have the ability to adjust bowl volume, media composition, media depth, underdrainage configuration, and vegetation type. This study exami...}, number={6}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Hunt, William F. and Davis, Allen P. and Traver, Robert G.}, year={2012}, month={Jun}, pages={698–707} }
 @article{pouliot_wisner_mobley_hunt_2012, title={Quantification of emission factor uncertainty}, volume={62}, ISSN={["2162-2906"]}, DOI={10.1080/10473289.2011.649155}, abstractNote={Emissions factors are important for estimating and characterizing emissions from sources of air pollution. There is no quantitative indication of uncertainty for these emission factors, most factors do not have an adequate data set to compute uncertainty, and it is very difficult to locate the data for those that do. The objectives are to compare the current emission factors of Electric Generating Unit NOX sources with currently available continuous emission monitoring data, develop quantitative uncertainty indicators for the Environmental Protection Agency (EPA) data quality rated emission factors, and determine the possible ranges of uncertainty associated with EPA's data quality rating of emission factors. EPA's data letter rating represents a general indication of the robustness of the emission factor and is assigned based on the estimated reliability of the tests used to develop the factor and on the quantity and representativeness of the data. Different sources and pollutants that have the same robustness in the measured emission factor and in the representativeness of the measured values are assumed to have a similar quantifiable uncertainty. For the purposes of comparison, we assume that the emission factor estimates from source categories with the same letter rating have enough robustness and consistency that we can quantify the uncertainty of these common emission factors based on the qualitative indication of data quality which is known for almost all factors. The results showed that EPA's current emission factor values for NOX emissions from combustion sources were found to be reasonably representative for some sources; however, AP-42 values should be updated for over half of the sources to reflect current data. The quantified uncertainty ranges were found to be 25–62% for A rated emission factors, 45–75% for B rated emission factors, 60–82% for C rated emission factors, and 69–86% for D rated emission factors, and 82–92% for E rated emission factors. Implications Currently, a letter grade indicates the data quality uncertainty of emission factors in EPA's Compilation of Emission Factors (AP-42). However, a quantitative characterization would be much preferred. If the uncertainty of emission factors is quantified, scientists may be able to more accurately characterize the uncertainty associated with air quality modeling and emission data. A quantitative measure of uncertainty will also give decision makers the ability to determine the confidence that should be placed in the analysis of the data being used for policy decisions.}, number={3}, journal={JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION}, author={Pouliot, George and Wisner, Emily and Mobley, David and Hunt, William, Jr.}, year={2012}, month={Mar}, pages={287–298} }
 @inproceedings{debusk_hunt_quigley_jeray_bedig_2012, title={Rainwater Harvesting: Integrating Water Conservation and Stormwater Management through Innovative Technologies}, ISBN={9780784412312}, url={http://dx.doi.org/10.1061/9780784412312.372}, DOI={10.1061/9780784412312.372}, abstractNote={Recent droughts, population increases, and predicted climate change have emphasized the fragility of water resources and the need for water conservation within the state of North Carolina, USA. The necessity of stormwater management is another ever-present reality for the state due to increases in urban development and resulting declines in water quality. Rainwater harvesting (RWH) systems are unique in their ability to provide an alternate source of water and serve as detention/retention for roof runoff that would otherwise be discharged to the stormwater network. This study focuses on two RWH systems, each of which employ an innovative method of increasing the stormwater management potential of the system: an active release mechanism and a passive release mechanism. The purpose of this study is to document how well RWH systems serve as both water conservation practices and stormwater management practices when equipped with these innovative technologies.}, booktitle={World Environmental and Water Resources Congress 2012}, publisher={American Society of Civil Engineers}, author={DeBusk, K. and Hunt, W. and Quigley, M. and Jeray, J. and Bedig, A.}, year={2012}, month={May} }
 @inproceedings{page_winston_hunt_2012, title={Stormwater Monitoring of Innovative Street Retrofits in Urban Wilmington, NC}, ISBN={9780784412312}, url={http://dx.doi.org/10.1061/9780784412312.056}, DOI={10.1061/9780784412312.056}, abstractNote={Many urban watersheds suffer from degraded water quality caused by stormwater runoff from rooftops, parking lots, streets and other impervious surfaces. Low Impact Development (LID) is a design approach that utilizes stormwater control measures (SCMs) to maintain and restore the natural hydrologic features of a watershed by promoting infiltration of runoff into the soil, treating runoff at its source, and minimizing impervious surface coverage. Peer-reviewed literature is lacking on the application of bioretention, permeable pavement and tree filter boxes to treat urban street runoff on a catchment-scale. A pre- and post-retrofit study has been designed to evaluate the impacts of catchment-scale retrofits on hydrology and water quality. The project will be implemented on two midblock street sections in a residential neighborhood in Wilmington, North Carolina. It includes construction of permeable pavement parking stalls, tree filter boxes and bioretention areas that extend into the street right-of-way, thereby reducing impervious surface area and increasing pedestrian safety. Runoff volumes and pollutant concentrations of bacteria, heavy metals, nutrients, polycyclic aromatic hydrocarbons (PAHs) and suspended solids were monitored from June 2011 to October 2011 at the retrofit site and an additional control site located four blocks to the West. Preliminary results from the pre-retrofit monitoring show mean concentrations of total Kjeldahl nitrogen (TKN) from the control and retrofit watersheds were 2.02 mg/L and 1.52 mg/L, respectively. Total phosphorus (TP) mean concentrations from the control and retrofit watersheds were similar at 0.31 mg/L and 0.29 mg/L, respectively. TKN and TP concentrations observed in this study at both monitoring sites were less than TKN and TP mean concentrations from National Urban Runoff Program (NURP) urban sites and NURP streets. Copper (Cu), lead (Pb) and zinc (Zn) mean concentrations from the control and retrofit watersheds were less than those reported from NURP urban sites and NURP streets. Total nitrogen (TN) and TP yearly loads were greater in the control watershed, which may be due to the greater fraction of impervious surface coverage and fertilizer use in the control watershed. The results and conclusions from this study will help refine street retrofit design standards to meet runoff volume reduction, peak discharge mitigation and water quality goals while increasing pedestrian safety and improving aesthetics in the neighborhood.}, booktitle={World Environmental and Water Resources Congress 2012}, publisher={American Society of Civil Engineers}, author={Page, J. L. and Winston, R. J. and Hunt, W. F.}, year={2012}, month={May} }
 @article{rauch_ledin_eriksson_deletic_hunt_2012, title={Stormwater in urban areas}, volume={46}, ISSN={["0043-1354"]}, DOI={10.1016/j.watres.2012.10.044}, abstractNote={Collection, storage and treatment of stormwater in urban areas has been one of the classical disciplines of sanitary and environmental engineering in the past. Waste and pollution transported by st ...}, number={20}, journal={WATER RESEARCH}, author={Rauch, Wolfgang and Ledin, Anna and Eriksson, Eva and Deletic, Ana and Hunt, William F., III}, year={2012}, month={Dec}, pages={6588–6588} }
 @article{hathaway_moore_burkholder_hunt_2012, title={Temporal analysis of stormwater control measure effluent based on windows of harmful algal bloom (HAB) sensitivity: Are annual nutrient EMCs appropriate during HAB-sensitive seasons?}, volume={49}, ISSN={0925-8574}, url={http://dx.doi.org/10.1016/j.ecoleng.2012.08.014}, DOI={10.1016/j.ecoleng.2012.08.014}, abstractNote={Nutrient removal by stormwater control measures (SCMs) is typically reported in terms of an average annual percent removal or effluent concentration. However, when the performance of these systems is considered in light of downstream receiving aquatic ecosystems, which display seasonal sensitivities to nutrient loadings, the use of an annual-based metric seems arbitrary. To investigate the potential temporal mismatch between nutrient-sensitive periods in receiving water bodies and average annual reporting periods adopted for SCM performance metrics, a case study is presented for four SCM types (constructed stormwater wetlands, bioretention, vegetated filter strips, and swales) draining to the Neuse River Estuary (NRE) in North Carolina, USA. Outbreaks of harmful algal blooms (HABs) in the NRE have been related to different nutrient forms at different times of the year, resulting in a “window” of importance for a given nutrient. These windows were utilized herein to define seasons of interest for various pollutants, and thus how SCM effluent data should be grouped to evaluate seasonal differences in performance. Effluent SCM nutrient concentrations were analyzed on an annual and HAB-sensitive seasonal basis. Although the use of annual performance metrics was deemed either appropriate or conservative for total phosphorus and nitrate–nitrite, effluent concentrations of total ammonia–nitrogen were significantly higher during HAB-sensitive seasons from both bioretention areas and stormwater wetlands. In the case of the NRE, these data suggest SCMs such as bioretention and stormwater wetlands may perform less effectively during periods of HAB sensitivity and that the contribution of SCMs to HAB control in sensitive water bodies may be overstated using presently accepted annual evaluation metrics. Though the seasonal analysis presented is specific to HAB formation in the Neuse River Estuary, evaluation of SCM effluent nutrient concentrations on the basis of nutrient-sensitive periods in receiving water bodies has broad application to evaluation of SCMs in any nutrient-sensitive watershed. The present study suggests that evaluation of SCM performance with respect to nutrient-sensitive periods in receiving aquatic ecosystems warrants further study.}, journal={Ecological Engineering}, publisher={Elsevier BV}, author={Hathaway, Jon M. and Moore, Trisha L.C. and Burkholder, JoAnn M. and Hunt, William F.}, year={2012}, month={Dec}, pages={41–47} }
 @article{winston_hunt_lord_2012, title={Thermal Mitigation of Urban Storm Water by Level Spreader-Vegetative Filter Strips (vol 137, pg 707, 2011)}, volume={138}, ISSN={["0733-9372"]}, DOI={10.1061/(asce)ee.1943-7870.0000587}, abstractNote={During composition, an error was introduced on p. 711 of the original paper. The text incorrectly indicates that an afternoon storm “occurred between 12 p.m. and 7 a.m.” This should have read “7 p.m.” The complete sentence is as follows: “Overnight storms were defined as those with rainfall occurring between 9 p.m. and 6 a.m., and afternoon storms occurred between 12 p.m. and 7 p.m.” ASCE regrets this error.}, number={11}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE}, author={Winston, R. J. and Hunt, W. F. and Lord, W. G.}, year={2012}, month={Nov}, pages={1165–1165} }
 @inproceedings{debusk_hunt_2012, title={Water Quality Benefits of Harvesting Rooftop Runoff}, ISBN={9780784412312}, url={http://dx.doi.org/10.1061/9780784412312.063}, DOI={10.1061/9780784412312.063}, abstractNote={It is well documented that runoff from roof surfaces carries a wide variety of pollutants including sediment, heavy metals, nutrients and bacteria. Collecting and storing this roof runoff via rainwater harvesting systems could provide water quality benefits due to physical and chemical processes that occur within the storage tank. Four fire stations in Raleigh, North Carolina, USA, were equipped with rainwater harvesting systems. Samples of roof runoff were collected after each storm to determine pre-cistern water quality characteristics. Samples were also collected at the extraction spigot for the system. All samples were analyzed for total suspended solids (TSS), total nitrogen (TN), total Kjeldahl nitrogen (TKN), nitrite (NO 2 )+nitrate (NO 3 ), ammonia (NH 3 ), and total phosphorus (TP). Water quality data will be analyzed to determine if storing water within a cistern has a significant effect on pollutant concentrations. Water usage data collected during the study period will be compiled and pollutant loads will be computed.}, booktitle={World Environmental and Water Resources Congress 2012}, publisher={American Society of Civil Engineers}, author={DeBusk, K. M. and Hunt, W. F.}, year={2012}, month={May} }
 @article{eck_winston_hunt_barrett_2012, title={Water Quality of Drainage from Permeable Friction Course}, volume={138}, ISSN={["0733-9372"]}, DOI={10.1061/(asce)ee.1943-7870.0000476}, abstractNote={An overlay of porous asphalt known as permeable friction course (PFC) is an innovative roadway material that improves both driving conditions in wet weather and water quality. Placed in a layer 25–50 mm thick on top of regular impermeable pavement, PFC allows rainfall to drain within the porous layer rather than on top of the pavement. This paper presents water quality measurements for PFC and conventional pavement collected over six years near Austin, TX and two years in eastern North Carolina. The data show that concentrations of total suspended solids from PFC are more than 90% lower than from conventional pavement. Lower effluent concentrations are also observed for total amounts of phosphorus, copper, lead, and zinc. The combined data sets show that PFC’s benefits last through the design life of the pavement, that results in Texas are consistent with those from North Carolina, and that both are consistent with earlier studies from France, the Netherlands, and Germany.}, number={2}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE}, author={Eck, Bradley J. and Winston, Ryan J. and Hunt, William F. and Barrett, Michael E.}, year={2012}, month={Feb}, pages={174–181} }
 @article{mcnett_hunt_2011, title={An Evaluation of the Toxicity of Accumulated Sediments in Forebays of Stormwater Wetlands and Wetponds}, volume={218}, ISSN={["1573-2932"]}, DOI={10.1007/s11270-010-0665-9}, number={1-4}, journal={WATER AIR AND SOIL POLLUTION}, author={McNett, Jacquelyn K. and Hunt, William F.}, year={2011}, month={Jun}, pages={529–538} }
 @inproceedings{wardynski_hunt_2011, title={Assessing the Accuracy of Bioretention Installation in North Carolina}, ISBN={9780784411735}, url={http://dx.doi.org/10.1061/41173(414)38}, DOI={10.1061/41173(414)38}, abstractNote={The performance of bioretention cells (BRCs) depends upon their capacity to store an adequate amount of runoff such that the desired stormwater volume and pollutant load are retained. Performance is also dependent upon the use of a suitable soil media that can provide storage within the void space, adequate infiltration between storm events, and substrate for plant and microbial interactions. Widespread construction of improperly designed cells could have substantial environmental consequences because of frequent overflow events. To determine if this is indeed a problem, 20 BRCs throughout North Carolina were assessed. Topographic surveys were performed and the as-built surface storage (ponding within the basin below the outlet elevation) was calculated using CAD software. Visual inspections of the soil profile were used to identify hydric soils and moisture regime. Particle-size distribution of the soil media at various depths was determined using the hydrometer method and permeability was estimated with constant-head saturated hydraulic conductivity tests. Results were compared to the intended storage volumes and soil specifications from original design calculations and construction plans. Preliminary findings show that 82% and 44% of BRC soil media failed to satisfy particle-size distribution and permeability specifications, respectively. Additionally, 50% of surveyed BRCs were either moderately or severely undersized. Continuing research will confirm whether BRCs throughout North Carolina are improperly installed and maintained. Research findings will be used to evaluate state requirements and provide recommendations to ensure that installed BRCs satisfy water quality and flood control regulations.}, booktitle={World Environmental and Water Resources Congress 2011}, publisher={American Society of Civil Engineers}, author={Wardynski, B. J. and Hunt, W. F.}, year={2011}, month={May} }
 @article{debusk_hunt_line_2011, title={Bioretention Outflow: Does It Mimic Nonurban Watershed Shallow Interflow?}, volume={16}, ISSN={["1943-5584"]}, DOI={10.1061/(asce)he.1943-5584.0000315}, abstractNote={Bioretention, a key structural practice of low impact development (LID), has been proved to decrease peak flow rates and volumes, promote infiltration and evapotranspiration, and improve water quality. Exactly how well bioretention mimics predevelopment (or “natural”) hydrology is an important research question. Do bioretention outflow rates mirror shallow groundwater interevent stream recharge flow associated with natural or nonurban watersheds? Streamflow from three small, nonurban watersheds, located in Piedmont, part of central North Carolina, was compared with bioretention outflow from four cells also in North Carolina’s Piedmont region. Each benchmark watershed drained to a small stream, where flow rate was monitored for an extended period of time. After normalizing the flow rates and volumes by watershed size, data were combined to form two data sets: bioretention outflow and stream interevent flow. Results indicate that there is no statistical difference between flow rates in streams draining unde...}, number={3}, journal={JOURNAL OF HYDROLOGIC ENGINEERING}, author={DeBusk, Kathy M. and Hunt, William F. and Line, Daniel E.}, year={2011}, month={Mar}, pages={274–279} }
 @inproceedings{debusk_hunt_2011, title={Bioretention Outflow: Does It Mimic Rural Water Interflow?}, ISBN={9780784411735}, url={http://dx.doi.org/10.1061/41173(414)41}, DOI={10.1061/41173(414)41}, abstractNote={Bioretention, a key structural practice of Low Impact Development (LID), has been proven to decrease peak flow rates and volumes, promote infiltration and evapotranspiration and improve water quality. Exactly how well bioretention mimics pre-development (or natural) hydrology is an important research question. Do bioretention outflow rates mirror shallow groundwater inter-event stream recharge flow associated with natural or non-urban watersheds? Streamflow from three small, non-urban watersheds, located in the Piedmont of central North Carolina, was compared to bioretention outflow from four cells also in North Carolina's Piedmont region. Each benchmark watershed drained to a small stream, where flow rate was monitored for an extended period of time. After normalizing the flow rates and volumes by watershed size, data were combined to form two data sets: bioretention outflow and stream inter-event flow. Results indicate that there is no statistical difference between flow rates in streams draining undeveloped watersheds and bioretention outflow rates for the first 24 hours following the commencement of flow. Similarly, there is no statistical difference between the cumulative volumes released by the two systems during the 48 hours following the start of flow. These results indicate that bioretention cells behave comparably to watersheds in natural or non-urban conditions with respect to both flow rates and flow volumes and suggest that bioretention outflows may mirror post storm event shallow groundwater inter-event stream recharge flow. Solely considering bioretention outflow as a conjugate to runoff may be a misinterpretation of a flowrate that actually resembles shallow interflow.}, booktitle={World Environmental and Water Resources Congress 2011}, publisher={American Society of Civil Engineers}, author={DeBusk, Kathy M. and Hunt, William F.}, year={2011}, month={May} }
 @article{hunt_greenway_moore_brown_kennedy_line_lord_2011, title={Constructed Storm-Water Wetland Installation and Maintenance: Are We Getting It Right?}, volume={137}, ISSN={0733-9437 1943-4774}, url={http://dx.doi.org/10.1061/(ASCE)IR.1943-4774.0000326}, DOI={10.1061/(ASCE)IR.1943-4774.0000326}, abstractNote={Constructed storm-water wetlands (CSWs) have become one of the more popular storm-water control measures (SCMs). CSWs offer a hybrid between larger detention technologies like storm-water wet ponds and newer green infrastructure technologies. The systems are characterized as being predominately shallow retention practices, with water elevations sufficiently low to support diverse flora and fauna. Figs. 1(a–c) illustrate several successful examples of CSWs. Many researchers have found that CSWs remove sediment, nutrients, and metals from storm-water runoff (Greenway 2004; Hathaway and Hunt 2010; Line et al. 2008; Kohler et al. 2004; Wadzuk et al. 2010). One of the principal drivers for the use of storm-water wetlands is the amount of credit awarded to them by various governmental agencies with respect to nutrient removal and sequestration [North Carolina Department of Environment and Natural Resources (NCDENR) 2009]. The apparent improvement in nutrient capture from storm-water runoff over that of storm-water wet ponds is one of the main reasons designers choose CSWs over the more traditional wet pond. Extensive coverage of vegetation allows for several pollutant removal mechanisms: filtration of particles, stabilization of sediments, nutrient uptake, microbialrhizophere interaction to promote nitrification and denitrification, and the provision of increased surface area for biofilm/periphyton growth (Greenway 2004). In regions where thermal loads threaten cold water fisheries, CSWs have been shown to release cooler water to streams than do wet ponds because of the shading caused by the vegetation—but absent from wet ponds (Jones and Hunt 2010). Some concerns have also presented themselves with respect to CSWs, which have prevented the practice from outright replacing the wet pond. Foremost among them is the threat of mosquito infestation that wetlands invariably face in relation to the public (QDNR 2000). Research has shown that exorbitantly high mosquito populations need not accompany CSWs, provided they are diversely vegetated (Greenway et al. 2003; Hunt et al. 2006). However, if wetlands are allowed to become monocultures of specific mosquito-protective plants, such as Typha spp. (commonly referred to as cattails in the United States), they can become the very mosquito breeding grounds that the public fears (Greenway et al. 2003; Hunt et al. 2005). If storm-water wetlands are to be constructed, they must both (1) meet their intended water quality (and hydrologic) design goals and (2) not be a public nuisance. Anecdotal observation of CSWs constructed worldwide shows how many well-intended CSW designs fail. Two principal reasons were identified: One appears to be that not enough care was taken to ensure the storm-water wetlands’ normal pool elevation was appropriately shallow (that is, often the elevation of water in CSWs is too deep). The cause has been previously identified by Greenway et al. (2007). The second is clogging of the outlet structure that artificially raises the elevation above normal pool for extended periods of time. In both cases, simple preventative actions could be taken to ensure constructed storm-water wetlands maintain their designed integrity. The purpose of this forum is to document how poor design and inadequate management of two CSWs caused each to effectively become wet ponds, which results in (1) a reduced efficiency in the removal of some pollutants; (2) a degradation of biodiversity, which leads to an increased risk of having the wetlands become mosquito breeding grounds; and (3) degraded aesthetics.}, number={8}, journal={Journal of Irrigation and Drainage Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Hunt, W. F. and Greenway, M. and Moore, T. C. and Brown, R. A. and Kennedy, S. G. and Line, D. E. and Lord, W. G.}, year={2011}, month={Aug}, pages={469–474} }
 @article{constructed storm-water wetland installation and maintenance: are we getting it right?_2011, volume={137}, number={8}, journal={Journal of Irrigation and Drainage Engineering}, year={2011}, pages={469–474} }
 @article{lenhart_hunt_2011, title={Evaluating Four Storm-Water Performance Metrics with a North Carolina Coastal Plain Storm-Water Wetland}, volume={137}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0000307}, abstractNote={Storm-water best management practices (BMPs) are typically assessed using the performance metric of pollutant concentration removal efficiencies. However, debate exists whether this is the most appropriate metric to use. In this study, a storm-water wetland constructed and monitored in the coastal plain of North Carolina is evaluated for water quality and hydrologic performance using four different metrics: concentration reduction, load reduction, comparison to nearby ambient water quality monitoring stations, and comparison to other wetlands studied in North Carolina. The River Bend storm-water wetland was constructed in spring 2007 and was monitored from June 2007 through May 2008. Twenty-four hydrologic and 11 water quality events were captured and evaluated. The wetland reduced peak flows and runoff volumes by 80 and 54%, respectively. Reductions were significant. Concentrations for the following pollutants increased: total kjeldahl nitrogen (TKN), NH4–N, total nitrogen (TN), and total suspended solid...}, number={2}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Lenhart, Hayes A. and Hunt, William F., III}, year={2011}, month={Feb}, pages={155–162} }
 @inproceedings{brown_hunt_2011, title={Evaluating Media Depth, Surface Storage Volume, and Presence of an Internal Water Storage Zone on Four Sets of Bioretention Cells in North Carolina}, ISBN={9780784411735}, url={http://dx.doi.org/10.1061/41173(414)44}, DOI={10.1061/41173(414)44}, abstractNote={Bioretention is becoming a widely used stormwater control measure (SCM) to achieve stringent stormwater regulations. This field study describes research performed on two sites in eastern North Carolina, where monitoring occurred for just over two years. At each site, there were two hydrologically separate bioretention cells. After the first year of research, a design specification was altered for both cells at each study site. Analysis for all cells included: (1) an annual runoff balance and (2) a calculation of concentration and pollutant load reductions for nitrogen species, phosphorus species, and total suspended solids. The bioretention cells in Rocky Mount, NC, were designed with an internal water storage (IWS) zone. The underdrain outlet was 0.3 and 0.6 m from the surface of the media in the first and second year, respectively. This feature had a major impact on runoff volume reduction. Each cell had a different underlying soil type; one was sand and the other sandy clay loam. Out of 151 monitored rainfall events over two years, outflow only occurred in 6 and 21 events, respectively. More drainage occurred in the cell with the tighter underlying soil and when the IWS zone was shallower due to less storage volume availability. The bioretention cells in Nashville, NC, were conventionally drained. They had varying media depths (0.6-m versus 0.9-m). During construction, they were severely undersized and clogged with fine sediment. After one year, the clogging layer was removed, which nearly doubled the surface storage volume and increased the infiltration rate by almost a factor of ten. The bioretention cells pre-repair were treating nearly 65 percent of annual runoff. After the repair, an additional 25 percent of annual runoff was treated. This improved the water quality treatment, reduced peak outflow rates, and reduced the duration of high outflow rates. Both sites demonstrated the impact that changing one of the design parameters has on the overall performance. For incorporating an IWS zone, the hydrologic and water quality performance appear dependent upon underlying soils and IWS zone depth. Results from the other site highlighted the importance of properly constructing and maintaining bioretention cells.}, booktitle={World Environmental and Water Resources Congress 2011}, publisher={American Society of Civil Engineers}, author={Brown, Robert A. and Hunt, William F.}, year={2011}, month={May} }
 @article{hathaway_hunt_2011, title={Evaluation of First Flush for Indicator Bacteria and Total Suspended Solids in Urban Stormwater Runoff}, volume={217}, ISSN={["1573-2932"]}, DOI={10.1007/s11270-010-0574-y}, number={1-4}, journal={WATER AIR AND SOIL POLLUTION}, author={Hathaway, Jon M. and Hunt, William F.}, year={2011}, month={May}, pages={135–147} }
 @article{luell_hunt_winston_2011, title={Evaluation of undersized bioretention stormwater control measures for treatment of highway bridge deck runoff}, volume={64}, ISSN={["1996-9732"]}, DOI={10.2166/wst.2011.736}, abstractNote={Two grassed bioretention cells were constructed in the easement of a bridge deck in Knightdale, North Carolina, USA, in October, 2009. One was intentionally undersized (‘small’), while the other was full sized (‘large’) per current North Carolina standards. The large and small cells captured runoff from the 25- and 8-mm events, respectively. Both bioretention cells employed average fill media depths of 0.65 m and internal water storage (IWS) zones of 0.6 m. Flow-proportional, composite water quality samples were collected and analyzed for nitrogen species, phosphorus species, and TSS. During 13 months of data collection, the large cell's median effluent concentrations and loads were less than those from the small cell. The small cell's TN and TSS load reductions were 84 and 50%, respectively, of those achieved by the large cell, with both cells significantly reducing TN and TSS. TP loads were not significantly reduced by either cell, likely due to low TP concentrations in the highway runoff which may have approached irreducible levels. Outflow pollutant loads from the large and small cell were not significantly different from one another for any of the examined pollutants. The small cell's relative performance provides support for retrofitting undersized systems in urbanized areas where there is insufficient space available for conventional full-sized stormwater treatment systems.}, number={4}, journal={WATER SCIENCE AND TECHNOLOGY}, author={Luell, S. K. and Hunt, W. F. and Winston, R. J.}, year={2011}, pages={974–979} }
 @article{hathaway_hunt_graves_bass_caldwell_2011, title={Exploring fecal indicator bacteria in a constructed stormwater wetland}, volume={63}, ISSN={["1996-9732"]}, DOI={10.2166/wst.2011.539}, abstractNote={Microbial pollution in surface waters is a concern throughout the world, with both public health and economic implications. One contributing source to such pollution is stormwater runoff, often treated using various types of stormwater control measures. However, relatively little is known regarding microbe sequestration in constructed stormwater wetlands (CSWs), one type of commonly installed stormwater control measure. In this study, indicator bacteria concentrations in both the water and sediment of a CSW were evaluated at multiple locations. Results suggested that fecal coliform concentrations in stormwater runoff decrease through the system, with relatively consistent concentrations noted throughout the second half of the wetland. This potentially indicates a baseline concentration of fecal coliform is present due to internal processes such as animal activity and microbial persistence. However, wetland sediments showed little E. coli present during most sampling events, with minimal patterns existing with respect to sediment sampling location. CSW designs should promote optimization of hydraulic retention time and minimization of stormwater velocities to promote sedimentation and degradation of microbes by way of wetland treatment functions.}, number={11}, journal={WATER SCIENCE AND TECHNOLOGY}, author={Hathaway, J. M. and Hunt, W. F. and Graves, A. K. and Bass, K. L. and Caldwell, A.}, year={2011}, pages={2707–2712} }
 @article{bright_burchell_hunt_price_2011, title={Feasibility of a Dune Infiltration System to Protect North Carolina Beaches from Fecal Bacteria Contaminated Storm Water}, volume={137}, ISSN={["0733-9372"]}, DOI={10.1061/(asce)ee.1943-7870.0000395}, abstractNote={Storm water ocean outfalls discharging into recreational waters pose a human health threat because of increased potential exposure to bacteria and other pathogens. The dune infiltration system (DIS) was designed and implemented at two ocean outfall sites in response to concerns by the North Carolina Department of Transportation and the town of Kure Beach, North Carolina The systems were designed to divert storm water runoff from 1.9 ha (4.7 acre) and 3.2 ha (8.0 acre) watersheds into the beach dunes. Following construction, data were collected from 25 storms during March through October 2006. The systems captured a combined total of nearly 1,800  m3 (63,500  ft3), or 95% of the influent storm water runoff—a significant reduction of runoff volume and peak flow discharging directly onto the beach (p<0.0001). Fecal coliform and enterococci concentrations were measured in the inflowing storm water runoff and groundwater downslope of the systems. Both groundwater bacteria concentrations near the systems were s...}, number={10}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE}, author={Bright, Tiffany M. and Burchell, Michael R. and Hunt, William F. and Price, William}, year={2011}, month={Oct}, pages={968–979} }
 @article{hathaway_hunt_graves_wright_2011, title={Field Evaluation of Bioretention Indicator Bacteria Sequestration in Wilmington, North Carolina}, volume={137}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0000444}, abstractNote={Although bioretention has been shown to remove or sequester a wide range of pollutants, relatively little study has been performed to evaluate its ability to sequester indicator bacteria. Two adjacent bioretention areas in Wilmington, North Carolina, were studied. The primary difference in the design of the two systems was soil depth. One bioretention cell was constructed with 25 cm of fill soil (Bioretention-S) and one with 60 cm of fill soil (Bioretention-D). The systems performed differently for indicator bacteria on the basis of multiple performance evaluation metrics. Bioretention-D showed concentration reductions of 70% and 89% for E. coli and enterococci, respectively. Effluent concentrations from Bioretention-D compared well to US EPA target values and other studies in literature. Conversely, Bioretention-S showed concentration “reductions” of -119% and -102% for E. coli and enterococci, respectively. Effluent concentrations from Bioretention-S were substantially higher than USEPA target values an...}, number={12}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Hathaway, J. M. and Hunt, W. F. and Graves, A. K. and Wright, J. D.}, year={2011}, month={Dec}, pages={1103–1113} }
 @article{winston_hunt_osmond_lord_woodward_2011, title={Field Evaluation of Four Level Spreader-Vegetative Filter Strips to Improve Urban Storm-Water Quality}, volume={137}, ISSN={["1943-4774"]}, DOI={10.1061/(asce)ir.1943-4774.0000173}, abstractNote={An assessment of the performance of four level spreader–vegetative filter strip (LS-VFS) systems designed to treat urban storm-water runoff was undertaken at two sites in the Piedmont of North Carolina. At each site, a 7.6-m grassed filter strip and a 15.2-m half-grassed, half-forested filter strip were examined. Monitored parameters included rainfall, inflow to, and outflow from each LS-VFS system. A total of 21 and 22 flow-proportional water quality samples were collected and analyzed for the Apex and Louisburg sites, respectively. All studied LS-VFS systems significantly reduced mean total suspended solids (TSS) concentrations (p<0.05), with the 7.6 and 15.2-m buffers reducing TSS by at least 51 and 67%, respectively. Both 15.2-m VFSs significantly reduced the concentrations of total Kjeldahl nitrogen (TKN), total nitrogen (TN), organic nitrogen (Org-N), and NH4-N (p<0.05), whereas results were mixed for the 7.6-m VFSs. Significant pollutant mass reduction was observed (p<0.05) for all nine pollutant f...}, number={3}, journal={JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING}, author={Winston, R. J. and Hunt, William F., III and Osmond, D. L. and Lord, W. G. and Woodward, M. D.}, year={2011}, month={Mar}, pages={170–182} }
 @inproceedings{hohaia_fassman_hunt_collins_2011, title={Hydraulic and Hydrologic Modelling of Permeable Pavement}, ISBN={9780784411735}, url={http://dx.doi.org/10.1061/41173(414)61}, DOI={10.1061/41173(414)61}, abstractNote={This current paper outlines the investigation procedures used to calibrate and verify a new hydrologic model on five permeable pavement structures in two different climates: Birkdale, New Zealand and North Carolina, USA. A beta version computer modelling package designed by the United States (US) Environmental Protection Agency (EPA), the Storm Water Management Model for Low Impact Design (SWMM5-LID(beta)), was used for the procedure. The calibrated model for the Birkdale site demonstrated accurate prediction of the system's response for both individual storms and continuous simulation (long-term). The model accurately predicts the peak flow response of the system for the highly frequent events (> 30% exceedance probability) with the measured and modelled flow frequency curves matching over this range. Volume control prediction is less accurate as the model over predicts retention for events greater than 10% exceedance by an average 4.7 mm. The calibrated model for the four North Carolina pavements (except for CGP) demonstrated accurate prediction for storms between 10 mm and 30 mm. The sand fill of the CGP provided additional storage which reduced peak underdrain outflow and volume. Modelling of this relationship requires significant modification of the fixed parameters in the model, which was not attempted. Simulated outflow hydrographs for storms <10 mm followed a similar shape to the measured hydrographs but over predicted the response. Simulated outflow hydrographs for storms >30 mm again had very similar shapes to the measured hydrographs but could not predict peak flows. Two parameters governed the response of the permeable pavement model: the drain coefficient and the drain exponent. A drain exponent of 3 is used in all of the models. A higher drain exponent increases the accuracy of the model but the corresponding drain coefficient becomes smaller and smaller. A calibrated drain coefficient of 0.000006 is used for the Birkdale site, and for the sites in North Carolina (PICP1, PICP2, CGP and PC) 0.00024, 0.001175, 0.00013 and 0.000725 respectively, were determined.}, booktitle={World Environmental and Water Resources Congress 2011}, publisher={American Society of Civil Engineers}, author={Hohaia, Nick and Fassman, Elizabeth and Hunt, William F. and Collins, Kelly A.}, year={2011}, month={May} }
 @article{brown_hunt_2011, title={Impacts of Media Depth on Effluent Water Quality and Hydrologic Performance of Undersized Bioretention Cells}, volume={137}, ISSN={["1943-4774"]}, DOI={10.1061/(asce)ir.1943-4774.0000167}, abstractNote={Fill media and excavation volume are the main costs in constructing bioretention cells, but the importance and impact of media depth in these systems is relatively unknown. Two sets of loamy-sand-filled bioretention cells of two media depths (0.6 m and 0.9 m), located in Nashville, North Carolina, were monitored from March 2008 to March 2009 to examine the impact of media depth on their performance with respect to hydrology and water quality. Construction and design errors resulted in the surface storage volume being undersized for the design event (2.5 cm). The actual surface storage volume was only 28% and 35% of the design volume for the 0.6-m and 0.9-m media depth cells, respectively. Overflow (bypass) occurred at least three times more frequently than intended. The exfiltration volume was much higher in the deeper media cells, presumably because of greater storage volume in the media and more exposure to side walls. Evapotranspiration (ET) plus exfiltration accounted for 42% of the inflow runoff in t...}, number={3}, journal={JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING}, author={Brown, Robert A. and Hunt, William F., III}, year={2011}, month={Mar}, pages={132–143} }
 @article{mcnett_hunt_davis_2011, title={Influent Pollutant Concentrations as Predictors of Effluent Pollutant Concentrations for Mid-Atlantic Bioretention}, volume={137}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0000373}, abstractNote={The water quality performance of best management practices (BMPs) has been frequently assessed by the removal efficiency metric. Recent findings show that the removal efficiency metric is flawed because it does not account for background water quality, eco-region differentiation, and background, or “irreducible,” concentrations. Additionally, the removal efficiency metric inherently assumes a definite association exists between influent and effluent pollutant concentrations. Such a relationship between influent and effluent concentrations has been minimally studied for bioretention, the most common storm-water control measure associated with low-impact development (LID). This study analyzes influent and effluent total nitrogen (TN) and total phosphorous (TP) concentrations from 11 bioretention cells in the mid-Atlantic United States. Pooled data showed only a slight association between influent and effluent TN. Essentially no relationship exists between influent and effluent TP concentration. Both finding...}, number={9}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={McNett, J. K. and Hunt, William F. and Davis, Allen P.}, year={2011}, month={Sep}, pages={790–799} }
 @article{moore_hunt_burchell_hathaway_2011, title={Organic nitrogen exports from urban stormwater wetlands in North Carolina}, volume={37}, ISSN={["1872-6992"]}, DOI={10.1016/j.ecoleng.2010.12.015}, abstractNote={Effluent organic nitrogen concentrations from seven constructed stormwater wetlands in North Carolina were examined to compare background organic nitrogen (ON) concentrations and the fraction of organic nitrogen relative to total nitrogen discharged. Seasonal influences on organic nitrogen concentrations were also examined. The median ON concentration from the stormwater wetlands was 0.78 mg l−1, and despite differences in wetland design and influent ON characteristics, outlet ON concentrations from all but one wetland were not significantly different. ON export from all stormwater wetlands was significantly less than untreated runoff entering the wetlands (p = 0.002). In addition, median organic:total nitrogen (ON:TN) ratios from stormwater wetlands (0.75) were significantly greater than from untreated urban runoff (0.66), comparing more closely to ON:TN ratios collected from a naturally occurring wetland and reported in the literature for natural landscapes. Seasonal differences in organic nitrogen concentrations were identified with significantly lower concentrations during the winter. Though stormwater wetlands will not (and perhaps should not be expected to) completely remove total nitrogen loads from runoff, these results suggest constructed wetlands can play a role in restoring the balance between organic and inorganic nitrogen forms closer to that of an undisturbed landscape. The presence of background organic nitrogen concentrations from stormwater wetlands similar to those from a naturally occurring wetland highlights the importance of choosing appropriate metrics (e.g., effluent concentrations) when assessing treatment performance.}, number={4}, journal={ECOLOGICAL ENGINEERING}, author={Moore, Trisha L. C. and Hunt, William F. and Burchell, Michael R. and Hathaway, Jon M.}, year={2011}, month={Apr}, pages={589–594} }
 @inproceedings{tillinghast_hunt_jennings_2011, title={Relating Stormwater Control Measure (SCM) Discharge Design Standards to Stream Erosion in Piedmont North Carolina: Case Studies in Raleigh and Chapel Hill, North Carolina}, ISBN={9780784411735}, url={http://dx.doi.org/10.1061/41173(414)54}, DOI={10.1061/41173(414)54}, abstractNote={watersheds become urbanized, the percent imperviousness increases, altering the hydraulics of stormwater runoff. To restore urbanized watersheds, stormwater control measures (SCMs) are often implemented and designed through water quality measures to return peak flow attenuation to a pre-developed state; however, the affect of release rates on the geomorphic stability of streams are often neglected. The SCMs reduce peak flow rates, but increase duration of sub-bankfull flows within channels, extending periods of erosion. Seventeen rural reference streams along with PCSWMM were used to 1) develop a power regression equation controlling maximum release rate of SCMs based on critical shear stresses of bed sediment and 2) develop annual allowable erosional hours and annual allowable volume of eroded sediment standards. These standards were then applied to 2 urbanized watersheds, House Creek in Raleigh, NC and Tanyard Branch in Chapel Hill, NC to assess the practicality of using the developed standards in an urbanized watershed and determine the geomorphic impact of using LID practices instead of a wet pond on a stream.}, booktitle={World Environmental and Water Resources Congress 2011}, publisher={American Society of Civil Engineers}, author={Tillinghast, E. D. and Hunt, W. F. and Jennings, G. D.}, year={2011}, month={May} }
 @article{traver_clark_hunt_struck_2011, title={Special Issue on Urban Storm-Water Management in the 21st Century Introduction}, volume={137}, ISSN={["1943-4774"]}, DOI={10.1061/(asce)ir.1943-4774.0000325}, abstractNote={As the practice of storm-water management evolves, so has our understanding of the tools. As we move away from a myopic flood control perspective, new tools to include what we now call green infrastructure best management practices (BMPs) were developed. Green roofs, rain gardens, and porous pavements appeared, with much of the design elements based on reasonable estimates of performance, thus the term “best.” Now we as a profession are moving toward a more engineered approach, with designs based on scientific knowledge of the processes, from soil physics and chemistry to hydrology and hydraulics. Soon it may be time to retire BMPs and move forward with the term “storm-water control measures,” as recommended by the National Academies authors of Urban Stormwater in the United States (National Research Council 2008). This issue of the Journal of Irrigation and Drainage Engineering is devoted to this evolving field of storm-water sustainability, and the effort to predict performance of our storm-water control measures. The 10 papers in this special issue reflect this evolution. Papers range from evaluating the concentration of effluent scoured from catch basins to cost-estimation tools, plus the inclusion of green-infrastructure tools within the International Stormwater BMP Database. Green and stone roofs are represented as are level spreaders. Bioretention/bioinfiltration rain gardens, however, received the most attention with papers on media depth, phosphorus removal, process modeling, mounding, and fines accumulation. This collection truly demonstrates our increasing knowledge base. This effort is a result of collaboration between the Stormwater Infrastructure Committee and Urban Water Resources Research Council, together with the Journal of Irrigation and Drainage Engineering Publications Committee. Conference proceedings from recent Environmental and Water Resources Institute (EWRI) congresses and low-impact development (LID) conferences were reviewed, and a select group of authors was invited to expand and revise their work. These papers passed through the standard journal peer-review process. We hope that this set of papers is of use to the profession. We would like to thank all the contributing authors, the reviewers, and William Ritter, as editor, for their efforts in this special issue.}, number={3}, journal={JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING}, author={Traver, Robert and Clark, Shirley and Hunt, William and Struck, Scott}, year={2011}, month={Mar}, pages={113–113} }
 @article{tillinghast_hunt_jennings_2011, title={Stormwater control measure (SCM) design standards to limit stream erosion for Piedmont North Carolina}, volume={411}, ISSN={["1879-2707"]}, DOI={10.1016/j.jhydrol.2011.09.027}, abstractNote={This study evaluated the potential impacts of sub-bankfull flows produced by stormwater control measures (SCMs) on stream geomorphic stability. In part, design standards for SCMs include peak flow attenuation to maintain pre-development flow conditions to those of undeveloped watersheds or return urbanized, developed watersheds back to the pre-developed state. Most SCMs target lower frequency storms, usually the 2-and/or 10-year discharge events, but leave peak flows resulting from higher frequency storms uncontrolled. SCMs are possibly subjecting streams to longer and more frequent periods of erosion, increasing stream channel instability. The d65 substrate size, pattern, profile, and dimension of 33 reference stream cross-sections in Piedmont North Carolina were modeled using the continuous simulations program, SWMM, to develop (1) a unit critical discharge metric in L/s/ha, Qc = 0.0035(d65)1.5048, (2) allowable annual erosional hour standard, Log(AAEH) = −1.26Log(d65) + 1.21, and (3) allowable volume of eroded bedload standard, Log(AV) = −0.64(Qc) − 1.52, for watersheds containing SCMs discharging into surface waters. The unit critical discharge represents a threshold that, once exceeded, incipient motion of the d65 particle can occur. These standards represented benchmarks of stable, naturally eroding reference streams. Ninety-four percent of the unit critical discharges were less than the 2-year 24-h event, indicating the necessity of controlling higher frequency sub-bankfull flows. The standards were applied to an urbanized watershed (one sub-catchment containing a structural SCM and two sub-catchments without) in Raleigh, North Carolina. The unit critical discharge metric appeared to adequately represent urbanized stream geomorphic processes for the sub-catchment undergoing urbanization (4.5% difference) but not for the mature urbanized sub-catchments (47.5% and 68.8% difference). Depending on the long-term management goal of the unstable stream, this metric is not applicable for all urbanized watersheds due to the discrepancy between the field and calculated unit critical discharges. Standards developed from urbanized reference streams could possibly better represent SCMs in urbanized watersheds. All three sub-catchments failed to meet the erosional standards demonstrating the ability of the standards to predict unstable geomorphic processes in streams. The addition of a detention SCM (wet pond), in the urbanized sub-catchment extended the duration of erosive flows from 37 to 87 h/ha/yr, but reduced the estimated volume of eroded bedload from 1.81 to 0.99 m3/m/ha/yr when compared to uncontrolled urbanization (no wet pond). Alterations to the design of the wet pond, increased volume size and change in orifice diameter, were explored to see if erosional standards could be better met. This study demonstrated the effect of current SCM design standards on stream stability and why geomorphic processes of stream channels should be incorporated in SCM design standards.}, number={3-4}, journal={JOURNAL OF HYDROLOGY}, author={Tillinghast, E. D. and Hunt, W. F. and Jennings, G. D.}, year={2011}, month={Dec}, pages={185–196} }
 @article{winston_hunt_lord_2011, title={Thermal Mitigation of Urban Storm Water by Level Spreader–Vegetative Filter Strips}, volume={137}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0000367}, DOI={10.1061/(ASCE)EE.1943-7870.0000367}, abstractNote={A study was conducted in Louisburg, North Carolina, to determine the effect of level spreader–vegetative filter strip (LS-VFS) storm-water control measures (SCMs) on runoff temperature and thermal loading. Two LS-VFS systems draining an urban catchment were monitored during the summers of 2008 and 2009. The first VFS was 7.6 m wide and entirely grassed. The second was 15.2 m wide, with the first-half grassed and the second-half wooded. Runoff temperatures and thermal loads from the urban catchment tended to peak toward the beginning of a storm event. Median and maximum storm temperatures were significantly reduced across both the 7.6-m and 15.2-m LS-VFSs. However, median and maximum effluent temperatures for both filter strip lengths were significantly greater than the 21°C trout threshold. Mean and median effluent temperatures from the 15.2-m LS-VFS were slightly lower (<1°C) than those from the 7.6-m LS-VFS, which may show the impact of increased filter strip width and/or the shading from wooded vegetat...}, number={8}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Winston, R. J. and Hunt, W. F. and Lord, W. G.}, year={2011}, month={Aug}, pages={707–716} }
 @inproceedings{luell_hunt_winston_2011, title={Treating Highway Bridge Deck Runoff Using Bioretention and a Swale}, ISBN={9780784411735}, url={http://dx.doi.org/10.1061/41173(414)40}, DOI={10.1061/41173(414)40}, abstractNote={A full sized bioretention cell, an undersized bioretention cell, and a swale were constructed in a bridge deck easement of I-540 in Knightdale, NC to treat bridge deck runoff. Runoff was piped from the northbound and southbound lanes to the bioretention cells and swale, respectively. Flow-weighted, composite water quality samples were collected at the inlets and outlets of the cells and the swale and were tested for nutrients, TSS, and heavy metals. The mean effluent concentration of TN released by the large cell, small cell, and swale were 0.38, 0.54, and 1.00 mg/L, respectively, while effluent TP concentrations were 0.10, 0.13, and 0.15 mg/L, respectively. Median TSS effluent concentrations were 16, 21, and 29 mg/L in the large cell, small cell, and swale, respectively. The large and small cells reduced runoff volumes by about 50% and 31%, respectively, for storms less than 2.54 cm. The swale reduced volumes by 3% for storms less than 2.54 cm. While both bioretention cells substantially reduced nutrient and sediment loads, the large cell outperformed the small cell. The small cell provided support for retrofitting undersized systems in areas with limited space. Both cells achieved greater pollutant and volume reductions than the swale.}, booktitle={World Environmental and Water Resources Congress 2011}, publisher={American Society of Civil Engineers}, author={Luell, S. K. and Hunt, W. F. and Winston, R. J.}, year={2011}, month={May} }
 @article{brown_hunt_2011, title={Underdrain Configuration to Enhance Bioretention Exfiltration to Reduce Pollutant Loads}, volume={137}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0000437}, abstractNote={The bioretention drainage configuration of raising the outlet to create an internal water storage (IWS) layer in the media was originally intended to promote denitrifying conditions. The goal was to reduce nitrate and total nitrogen concentrations in nutrient-sensitive watersheds. Two field studies in the Piedmont region of North Carolina, where the in situ soils typically have high clay content, showed this design feature had potential to enhance exfiltration and reduce drainage from bioretention. Two bioretention cells in Rocky Mount, North Carolina, were monitored for two year-long periods to measure the impact of varying IWS zone depths over sandier underlying soils. Nearly 99% of runoff entering the bioretention cell with sand underlying soil (sand cell) was never directly discharged to the storm water network. However, the hydraulic retention time (contact time) of runoff in the media was less than 3 h, and except for total suspended solids (TSS), minimal pollutant removal was achieved. The other bi...}, number={11}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Brown, R. A. and Hunt, W. F.}, year={2011}, month={Nov}, pages={1082–1091} }
 @inproceedings{debusk_hunt_2010, title={Alternative Site-Assessment Hydrologic Metrics for Urban Development}, ISBN={9780784410998}, url={http://dx.doi.org/10.1061/41099(367)58}, DOI={10.1061/41099(367)58}, abstractNote={While LID techniques are becoming more commonplace across the United States, there is no universally-accepted method for evaluating how well a site adheres to LID principles; namely, how closely the post-development hydrology mimics predevelopment (or target) hydrology. As part of the Sustainable Sites InitiativeTM (www.sustainablesites.org) a method was developed to assess the pre- and post-development hydrology of a site and provide a means for a currently built upon site (a greyfield) to receive credit for partial restoration of hydrology. The Stormwater Management Model (SWMM) was used to model runoff at five locations across the U.S. for 10 years, with varying degrees of urbanization represented by a range of curve numbers. Based on natural soil type and vegetative cover, a target curve number was assigned to each location. A watershed's runoff flow volume and rates were calculated for each curve number and the change in flow volumes were then calculated relative to the target curve number. The percent decrease was then assigned a point value which a developer could potentially use for credit, similar to the U.S. Green Building Council's LEED® program. Graphical representations of hydrologic conditions and corresponding point values were developed. This method provides developers and regulators with a tangible, numeric goal for post-development hydrology when retrofitting developed sites while allowing flexibility in how that goal is achieved. The analysis of additional locations could provide the means for this approach to become the primary method across the country to evaluate a site's adherence to LID hydrologic principles.}, booktitle={Low Impact Development 2010}, publisher={American Society of Civil Engineers}, author={DeBusk, K. M. and Hunt, W. F.}, year={2010}, month={Apr} }
 @inproceedings{debusk_hunt_2010, title={Alternative Site-Assessment Hydrologic Metrics for Urban Development}, ISBN={9780784411148}, url={http://dx.doi.org/10.1061/41114(371)415}, DOI={10.1061/41114(371)415}, abstractNote={While LID techniques are becoming more commonplace across the United States, there is no universally-accepted method for evaluating how well a site adheres to LID principles; namely, how closely the post-development hydrology mimics pre-development (or target) hydrology. As part of the Sustainable Sites InitiativeTM (www.sustainablesites.org) a method was developed to assess the pre- and post-development hydrology of a site and provide a means for a currently built upon site (a greyfield) to receive credit for partial restoration of hydrology. The Stormwater Management Model (SWMM) was used to model runoff at five locations across the U.S. for 10 years, with varying degrees of urbanization represented by a range of curve numbers. Based on natural soil type and vegetative cover, a target curve number was assigned to each location. A watershed's runoff flow volume and rates were calculated for each curve number and the change in flow volumes were then calculated relative to the target curve number. The percent decrease was then assigned a point value which a developer could potentially use for credit, similar to the U.S. Green Building Council's LEED® program. Graphical representations of hydrologic conditions and corresponding point values were developed. This method provides developers and regulators with a tangible, numeric goal for post-development hydrology when retrofitting developed sites while allowing flexibility in how that goal is achieved. The analysis of additional locations could provide the means for this approach to become the primary method across the country to evaluate a site's adherence to LID hydrologic principles.}, booktitle={World Environmental and Water Resources Congress 2010}, publisher={American Society of Civil Engineers}, author={DeBusk, K. M. and Hunt, W. F.}, year={2010}, month={May} }
 @inproceedings{debusk_hunt_line_2010, title={Bioretention Outflow: Does It Mimic Non-Urban Watershed Shallow Interflow?}, ISBN={9780784410998}, url={http://dx.doi.org/10.1061/41099(367)105}, DOI={10.1061/41099(367)105}, abstractNote={Bioretention, a key structural practice of Low Impact Development (LID), has been proven to decrease peak flow rates and volumes, promote infiltration and evapotranspiration and improve water quality. Exactly how well bioretention mimics pre-development (or "natural") hydrology is an important question that continues to be researched. Do bioretention outflow rates mirror shallow groundwater inter-event stream recharge flow associated with natural or non-urban watersheds? Streamflow from three small, non-urban watersheds, located in the piedmont of central North Carolina, was compared to bioretention outflow from four cells also in North Carolina's Piedmont region. Each benchmark watershed drained to a small stream, where flow rate was monitored for an extended period of time. After normalizing the flow rates and volumes by watershed size, data were combined to form two data sets: bioretention outflow and stream inter-event flow. Results indicate that there is no statistical difference between flow rates in streams draining undeveloped watersheds and bioretention outflow rates for the first 24 hours following the commencement of flow. Similarly, there is no statistical difference between the cumulative volumes released by the two systems during the 48 hours following the start of flow. These results indicate that bioretention cells behave comparably to watersheds in natural or non-urban conditions with respect to both flow rates and flow volumes and that bioretention outflows somewhat mirror post storm event shallow groundwater recharge. Solely considering bioretention outflow as a conjugate to runoff may be a misinterpretation of a flowrate that actually resembles shallow interflow.}, booktitle={Low Impact Development 2010}, publisher={American Society of Civil Engineers}, author={DeBusk, K. M. and Hunt, W. F. and Line, D. E.}, year={2010}, month={Apr} }
 @inproceedings{debusk_hunt_line_2010, title={Bioretention Outflow: Does it Mimic Non-Urban Watershed Shallow Interflow?}, ISBN={9780784411148}, url={http://dx.doi.org/10.1061/41114(371)313}, DOI={10.1061/41114(371)313}, abstractNote={Bioretention, a key structural practice of Low Impact Development (LID), has been proven to decrease peak flow rates and volumes, promote infiltration and evapotranspiration and improve water quality. Exactly how well bioretention mimics pre-development (or natural) hydrology is an important question that continues to be researched. Do bioretention outflow rates mirror shallow groundwater inter-event stream recharge flow associated with natural watersheds? Three small, undeveloped watersheds, located in the piedmont of central North Carolina, were chosen to represent natural hydrology. These watersheds ranged from 50 to 78ha and were comprised primarily of forest and pastureland. Each drained to a small stream, where flow rate was monitored for an extended period of time. Data collected from the natural watersheds was compared to outflow rates from four bioretention cells. The cells selected are located within the piedmont region and drain predominantly urban watersheds ranging from 0.2 to 0.9ha in size. Flow rates and cumulative volumes were determined for each site at the following intervals after stormflow/outflow began: 3, 6, 12, 18, 24, 30, 36, 42 and 48 hours. After normalizing the flow rates and volumes by watershed size, data were combined to form two data sets: bioretention outflow and stream inter-event flow. Nonparametric statistical analyses were performed on the datasets using the Wilcoxon signed rank test. Results indicate that there is no statistical difference between flow rates in streams draining undeveloped watersheds and bioretention outflow rates for the first 24 hours following the commencement of flow. Similarly, there is no statistical difference between the cumulative volumes released by the two systems during the 48 hours following the start of flow. These results indicate that bioretention cells behave comparably to natural, undeveloped conditions with respect to both flow rates and flow volumes and that bioretention outflows somewhat mirrow post storm event shallow groundwater recharge.}, booktitle={World Environmental and Water Resources Congress 2010}, publisher={American Society of Civil Engineers}, author={DeBusk, K. M. and Hunt, W. F. and Line, D. E.}, year={2010}, month={May} }
 @inproceedings{winston_hunt_debusk_woodward_hartup_2010, title={Certifying the Landscape Community in Rain Garden Installation: The North Carolina Experience}, ISBN={9780784410998}, url={http://dx.doi.org/10.1061/41099(367)50}, DOI={10.1061/41099(367)50}, abstractNote={Low Impact Development (LID) stormwater practices are being utilized to a greater extent in new construction to mitigate pollutant loads and hydrologic impacts associated with development. However, many cities are faced with existing non-LID developments, and may be forced, through legislation, to implement stormwater retrofits. Homeowners are often interested in improving water quality in their neighborhood, and backyard rain gardens are one practice that have become popular in North Carolina. Few homeowners have the technical knowledge to size and construct a rain garden; therefore, they often hire a landscaper to complete these tasks. Faculty at N.C. State University and extension agents in the N.C. Cooperative Extension have developed a 1.5 day certification course that offers landscapers a detailed understanding of how to properly site, design, install, and maintain a residential rain garden. Attendees listen to six hours of presentations on rain gardens, and then take a two hour tour of local rain gardens that have previously been installed. On the second day of the workshop, attendees take both an in-class and a field exam. Four workshops have been delivered in the past 9 months, with a total of 73 people certified. Some of these landscapers are actively advertising their certification. Similar programs could easily translate to other communities throughout the country. Rain gardens help to control runoff at its source, and may make meeting watershed-wide LID hydrology goals easier to obtain.}, booktitle={Low Impact Development 2010}, publisher={American Society of Civil Engineers}, author={Winston, Ryan J. and Hunt, William F. and DeBusk, Kathy M. and Woodward, Mitchell D. and Hartup, Wendi W.}, year={2010}, month={Apr} }
 @inproceedings{brown_line_hunt_lord_2010, title={Comparison of Low Impact Development Treatment, Traditional Stormwater Treatment, and No Stormwater Treatment for Commercial Shopping Centers in North Carolina}, ISBN={9780784410998}, url={http://dx.doi.org/10.1061/41099(367)61}, DOI={10.1061/41099(367)61}, abstractNote={Low impact development (LID) stormwater practices are becoming more popular because of their ability to improve water quality and recharge groundwater. New regulations require water quality treatment of stormwater runoff in addition to reducing peak flows, especially in nutrient sensitive watersheds. Previously, the main focus of traditional stormwater practices had been on mitigating flooding and reducing peak flows; whereas, newer LID practices improve water quality and attempt to restore a site's natural or pre-developed hydrology. This is accomplished by promoting more evapotranspiration and infiltration. Three commercial shopping centers have been monitored from April 2008 to September 2009 to measure the performance of using LID stormwater treatment, traditional stormwater treatment, or no stormwater treatment. All three sites were monitored for water quality and hydrology, and they were located within 70-km of each other. The site with no stormwater treatment and the site with traditional stormwater treatment were located in Raleigh, NC, and the site with LID treatment was located in Nashville, NC. Since the sites did not receive the same precipitation depths for each storm, the hydrology data were normalized per area treated. The LID practices were designed to treat the first flush of runoff or water quality event. The LID site incorporated the use of bioretention, permeable concrete, and constructed wetlands. Seven bioretention cells of varying media depths (0.6-m and 0.9-m) treated the front asphalt parking lot, and permeable concrete treated the rear parking lot. Storage was added beneath the permeable concrete to completely capture a 2.5-cm event. The constructed wetlands treated rooftop runoff, miscellaneous paved areas, and outparcel lots. Each LID practice was monitored as a separate unit and the site was monitored as a whole system. Effluent was monitored from the retention basin at the site with traditional stormwater treatment. A mixture of parking lot and rooftop runoff was monitored at the site with no stormwater controls. In addition to the water quality and hydrology results, much was learned about the construction and implementation of multiple and large scale LID practices at one site. LID practices are typically more sensitive practices, so proper construction oversight, installation, and maintenance are vital to adequate functioning of these stormwater treatment devices. Errors at this site included: undersized bioretention cells, clogged bioretention cells, a continuously flowing bioretention cell due to interception of the water table, and constructed wetlands that remained flooded, resulting in vegetation die off.}, booktitle={Low Impact Development 2010}, publisher={American Society of Civil Engineers}, author={Brown, Robert A. and Line, Daniel E. and Hunt, William F. and Lord, William G.}, year={2010}, month={Apr} }
 @inproceedings{debusk_wright_hunt_2010, title={Demonstration and Monitoring of Rainwater Harvesting Technology in North Carolina}, ISBN={9780784410998}, url={http://dx.doi.org/10.1061/41099(367)1}, DOI={10.1061/41099(367)1}, abstractNote={Water conservation has grown in importance across North Carolina, as much of the state has recently suffered moderate to severe drought conditions. In addition to meeting water conservation needs, rainwater harvesting systems (cisterns) have an important application in low impact development (LID) as innovative stormwater management practices. A total of three cisterns were installed in each of the main physiographic regions of North Carolina: Craven County (coastal plain), Guilford County (piedmont), and Watauga County (mountain). These systems demonstrate above ground and partially buried applications. Uses for the captured stormwater include irrigating landscapes and gardens, washing vehicles, an additive for brine applied to icy streets and flushing kennels at an animal shelter. Each site is being monitored for water quantity and usage, and one system is monitored for water quality. Results will help establish the water quantity and quality benefits of rainwater harvesting systems and will influence design recommendations to be incorporated in the State of North Carolina's new Stormwater BMP Design Manual.}, booktitle={Low Impact Development 2010}, publisher={American Society of Civil Engineers}, author={DeBusk, K. M. and Wright, J. D. and Hunt, W. F.}, year={2010}, month={Apr} }
 @inproceedings{debusk_hunt_wright_2010, title={Demonstration and Monitoring of Rainwater Harvesting Technology in North Carolina}, ISBN={9780784411148}, url={http://dx.doi.org/10.1061/41114(371)51}, DOI={10.1061/41114(371)51}, abstractNote={Water conservation has grown in importance across North Carolina, as much of the state has recently suffered moderate to severe drought conditions. In addition to meeting water conservation needs, rainwater harvesting systems (cisterns) have an important application in low impact development (LID) as innovative stormwater management practices. A total of three cisterns were installed in each of the main physiographic regions of North Carolina: Craven County (coastal plain), Guilford County (piedmont), and Watauga County (mountain). These systems demonstrate above ground and partially buried applications. Uses for the captured stormwater include irrigating landscapes and gardens, washing vehicles, an additive for brine applied to icy streets and flushing kennels at an animal shelter. Each site is being monitored for water quantity and usage, and one system is monitored for water quality. Results will help establish the water quantity and quality benefits of rainwater harvesting systems and will influence design recommendations to be incorporated in the State of North Carolina's new Stormwater BMP Design Manual.}, booktitle={World Environmental and Water Resources Congress 2010}, publisher={American Society of Civil Engineers}, author={DeBusk, K. M. and Hunt, W. F. and Wright, J. D.}, year={2010}, month={May} }
 @article{jones_hunt_2010, title={Effect of Storm-Water Wetlands and Wet Ponds on Runoff Temperature in Trout Sensitive Waters}, volume={136}, ISSN={["1943-4774"]}, DOI={10.1061/(asce)ir.1943-4774.0000227}, abstractNote={With increasing development in areas of trout sensitive waters, the effect of urban storm-water runoff temperature on the aquatic ecosystem has become a concern. A study was conducted in western North Carolina, along the southeastern extent of U.S. trout populations, to determine the effect of storm-water wetlands and wet ponds on the temperature of urban storm-water runoff. Measurements included temperature at the inlets, outlets, and at several depths within the best management practices (BMPs). Parking lot runoff temperatures were significantly higher than the 21°C temperature threshold for trout during peak summer months and water temperatures consistently increased from the inlet to the outlet in the storm-water wetland and wet pond, implicating these BMPs as sources of thermal pollution. Despite similar inflow temperatures, effluent temperatures from the wet pond were significantly warmer than those from the storm-water wetland for the period from June to September. Substantial cooling was observed ...}, number={9}, journal={JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING}, author={Jones, Matthew P. and Hunt, William F.}, year={2010}, month={Sep}, pages={656–661} }
 @article{mcnett_hunt_osborne_2010, title={Establishing Storm-Water BMP Evaluation Metrics Based upon Ambient Water Quality Associated with Benthic Macroinvertebrate Populations}, volume={136}, ISSN={["0733-9372"]}, DOI={10.1061/(asce)ee.1943-7870.0000185}, abstractNote={Storm-water experts agree that the currently used best management practice (BMP) percent removal methodology metric has many flaws, and some have suggested using a BMP effluent concentration metric. This case study examines establishing an effluent target concentration for BMPs that relates to the health of macroinvertebrates in the receiving water. In North Carolina, 193 ambient water quality monitoring stations were paired with benthic macroinvertebrate health ratings collected in very close proximity. Water quality for the sites ranged from excellent to poor and was divided into three distinct ecoregions: Mountain, Piedmont, and Coastal. Statistically significant relationships were found in one or more ecoregions for dissolved oxygen, fecal coliform, NH3 , NO2−3 − N , total Kjeldahl nitrogen, total nitrogen (TN), and total phosphorus (TP). BMPs can then be selected and designed to meet these target effluent concentrations. Based upon this research, a development, and therefore set of BMPs, in Piedmont ...}, number={5}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE}, author={McNett, Jacquelyn K. and Hunt, William F. and Osborne, Jason A.}, year={2010}, month={May}, pages={535–541} }
 @inproceedings{hathaway_hunt_2010, title={Evaluation of Indicator Bacteria Export from an Urban Watershed}, ISBN={9780784411148}, url={http://dx.doi.org/10.1061/41114(371)355}, DOI={10.1061/41114(371)355}, abstractNote={Studies have shown stormwater runoff is a contributor to elevated indicator bacteria concentrations in surface waters. These elevated concentrations may indicate a heightened human health risk and lead to water quality violations as concentrations exceed regulatory standards. Total Maximum Daily Loads (TMDLs) are commonly established for indicator bacteria, requiring modeling and watershed planning to reduce loadings. However, factors correlated to indicator bacteria build-up and transport in urban watersheds have not been fully explored. Thus, efforts to manage indicator bacteria in urban watersheds are hampered. A watershed monitoring study in Raleigh, North Carolina, used flow weighted samples to provide detailed mass loadings of fecal coliform, E. coli, and enterococcus from a 5.1 ha (12.5-acre) residential watershed. Loads were compared to multiple antecedent and in-storm hydrologic and meteorological parameters. The objective of this study was to determine which, if any, parameters can be linked to changes in indicator bacteria export from urban watersheds and to identify patterns in intra-storm indicator bacteria transport. This study will lead to a further understanding of how indicator bacteria can be modeled and managed in urban watersheds.}, booktitle={World Environmental and Water Resources Congress 2010}, publisher={American Society of Civil Engineers}, author={Hathaway, J. M. and Hunt, W. F.}, year={2010}, month={May} }
 @inproceedings{winston_hunt_wright_2010, title={Evaluation of Roadside Filter Strips, Dry Swales, Wet Swales, and Porous Friction Course for Stormwater Treatment}, ISBN={9780784410998}, url={http://dx.doi.org/10.1061/41099(367)109}, DOI={10.1061/41099(367)109}, abstractNote={Due to NPDES regulations, the North Carolina Department of Transportation (NC DOT) is required to treat stormwater from NC DOT facilities throughout North Carolina. There are hundreds of miles of existing right-of-way swales and filter strips across North Carolina. Relatively few roadside swales and filter strips have been tested for water quantity and quality control. Also, no studies exist on swales with wetland characteristics. This paper presents an assessment of dry swale, wetland swale, and filter strip performance along an interstate highway in North Carolina. Four existing right-of-way linear swales along I-40 were monitored to determine their hydrologic and water quality effectiveness. Two different treatments were examined: one dry swale and one which was allowed to establish wetland vegetation and hydrology. This experimental design was replicated once. Also addressed was the impact of the vegetated filter strip between the shoulder and the edge of the swale. Samples have been collected from 17–21 events (depending on the site) and analyzed for TKN, NO2–3-N, TN, NH4-N, Organic-N, TP, and TSS. It should be noted that this section of highway had a porous friction course (PFC) applied, which had an impact on swale and filter strip performance. Mean effluent TN concentrations were lower for the swales with wetland characteristics than the non-wetland swales. No such difference was observed for TP effluent concentrations. TP concentrations measured at the edge-of-highway were low (mean < 0.11 mg/L) at all four sites, resulting in poor reduction ofTPEMCs by the swales and roadside filter strips. Due to the presence of a porous friction course on the highway, mean TSS concentrations from the roadway were below 32 mg/L at all four sites. Effluent concentrations of TSS from both the swales and filter strips were higher than edge-of-pavement concentrations. The swales and filter strips did not perform well using traditional concentration reduction metrics for TP and TSS; this was mainly due to the lower sediment-bound pollutant concentrations derived from the porous friction course overlay.}, booktitle={Low Impact Development 2010}, publisher={American Society of Civil Engineers}, author={Winston, R. J. and Hunt, W. F. and Wright, J. D.}, year={2010}, month={Apr} }
 @article{hathaway_hunt_2010, title={Evaluation of Storm-Water Wetlands in Series in Piedmont North Carolina}, volume={136}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0000130}, abstractNote={Three storm-water wetlands in series were monitored in a heavily urbanized 12.5 ha watershed in Mooresville, North Carolina. Monitoring of this system allowed an examination of the diminishing returns provided by three successive best management practices (BMPs) of a similar type. At least 80% of the total concentration reduction for all pollutants occurred within the first wetland cell. Only the first wetland cell significantly ( p<0.05 ) reduced all pollutants tested. No pollutant was significantly reduced from the outlet of Wetland Cell 2 to the outlet of Wetland Cell 3 ( p<0.05 ) . Median complete system (outlet of Wetland Cell 3) effluent concentrations for total suspended solids, total phosphorus, total nitrogen, and turbidity were 8, 0.09, 0.73 mg/L, and 10 NTU, respectively, which compared favorably to published results. Organic nitrogen generated from wetland vegetation seemed to result in a background source of nitrogen in the wetlands, supporting the idea of an irreducible concentration for nit...}, number={1}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Hathaway, J. M. and Hunt, W. F.}, year={2010}, month={Jan}, pages={140–146} }
 @inproceedings{brown_hunt_2010, title={Impact of Maintenance and (Im)Properly Sizing Bioretention on Hydrologic and Water Quality Performance}, ISBN={9780784410998}, url={http://dx.doi.org/10.1061/41099(367)9}, DOI={10.1061/41099(367)9}, abstractNote={Bioretention is one of the most common low impact development (LID) stormwater practices. Two sets of bioretention cells of varying media depths (0.6-m and 0.9-m) will have been monitored for two, 12-month periods, in Nashville, NC. They treat runoff from an impervious asphalt parking lot. During the first monitoring period, the bioretention cells were clogged with sediment from construction and were severely undersized. Complete drawdown of the surface storage took approximately 48 hours or more, as compared to the recommended 12 hours. Initially, the surface storage volumes for the 0.6-m and 0.9-m media depth cells were 36 percent and 46 percent of the design storage volume, respectively. The bioretention cells were designed to treat the 2.5-cm event, but the system became overwhelmed and overflow occurred for events as small as 0.8 cm. Overflow was occurring three times more frequently than intended. In March 2009, a contractor removed the fines layer that was present in the top 7.6-cm. Through removal of this layer and expanding the surface area, the surface storage volume was increased by 89 percent for both cells. With the increase in surface storage volume, more runoff has been treated, and the system was overwhelmed less frequently. The volume of overflow has been reduced to approximately one-third of the volume, as compared to the first monitoring period. Moreover, removing the fines layer has increased surface drawdown rate by at least 10 times. This site was also monitored for water quality. Nitrogen and phosphorus species and total suspended solids were measured. The results of this study show the importance of properly constructing and maintaining bioretention cells. Undersizing a bioretention cell as a result of a small construction error in setting the base elevation for the bottom of the bowl or the emergency overflow structure will result in a reduction in performance.}, booktitle={Low Impact Development 2010}, publisher={American Society of Civil Engineers}, author={Brown, Robert A. and Hunt, William F.}, year={2010}, month={Apr} }
 @inproceedings{brown_hunt_2010, title={Impact of Maintenance and (Im)Properly Sizing Bioretention on Hydrologic and Water Quality Performance}, ISBN={9780784411148}, url={http://dx.doi.org/10.1061/41114(371)312}, DOI={10.1061/41114(371)312}, abstractNote={Routine maintenance and proper construction oversight both need to occur during and after bioretention cell construction, in order to ensure proper functionality. Two sets of bioretention cells of varying media depths (0.6-m and 0.9-m) have been monitored for two, 12-month periods, in Nashville, NC. These bioretention cells are unique in that during the first monitoring period, the bioretention cells were (1) clogged with fine sediment from construction and (2) were severely undersized. Complete drawdown of the surface storage took 48 hours or more, as compared to the recommended 12 hours. Initially, the surface storage volumes for the 0.6-m and 0.9-m media depth cells were only 28 percent and 35 percent of the design storage volume, respectively. The design event for the bioretention cells at this site was 2.5-cm, but the system was overwhelmed frequently and overflow occurred for events as small as 0.9 cm. After one year of monitoring, the fines layer present in the top 7.6-cm was removed. Removal of this layer increased the surface storage volume of both sets of cells by 89 percent. With the increase in surface storage volume, more runoff was treated, and fewer events had overflow. The smallest event with overflow was 1.9 cm, and some events up to 2.8 cm were fully captured in the bowl. Overflow volume was reduced to approximately one-third of the volume from the first monitoring period. Moreover, removal of the fines layer increased the surface drawdown rate by up to a factor of 10. Pollutant load reductions increased for nitrogen species and total suspended solids because more runoff was treated. The results of this study highlight the reduced performance associated with improperly constructed and maintained bioretention cells. Even a small construction error in setting the base elevation for the bottom of the bowl or the emergency overflow structure can drastically reduce the bowl storage volume.}, booktitle={World Environmental and Water Resources Congress 2010}, publisher={American Society of Civil Engineers}, author={Brown, Robert A. and Hunt, William F.}, year={2010}, month={May} }
 @article{bright_hathaway_hunt_reyes_burchell_2010, title={Impact of Storm-Water Runoff on Clogging and Fecal Bacteria Reduction in Sand Columns}, volume={136}, ISSN={["1943-7870"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-78651504665&partnerID=MN8TOARS}, DOI={10.1061/(asce)ee.1943-7870.0000280}, abstractNote={Storm-water runoff has been identified as a major cause of coastal water quality degradation. Storm-water outfalls, common in many coastal towns, convey bacteria and other pollutants into the ocean and estuaries. In an effort to minimize this impact, the Town of Kure Beach, North Carolina, installed Dune Infiltration Systems (DIS) at two storm-water outfalls to receive storm-water runoff and allow infiltration beneath the beach dunes. A laboratory column experiment was performed to supplement this installation and determine the potential hydraulic and bacterial removal efficiency of the sand comprising the Kure Beach dunes. Columns constructed using sand collected at different depths of the dune were used to analyze the affect of bacteria application on infiltration and to examine the changes in bacteria removal that occur as infiltration rates are affected by bacteria-laden water application. Sand columns were loaded over a 60-day period with either bacteria-free storm water or storm water spiked with Es...}, number={12}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Bright, T. M. and Hathaway, J. M. and Hunt, W. F., III and Reyes, F. L., III and Burchell, M. R., III}, year={2010}, month={Dec}, pages={1435–1441} }
 @article{brown_hunt_2010, title={Impacts of Construction Activity on Bioretention Performance}, volume={15}, ISSN={["1943-5584"]}, DOI={10.1061/(asce)he.1943-5584.0000165}, abstractNote={Bioretention cells are incorporated as part of low impact development LID because of their ability to release influent runoff as exfiltration to the soil or evapotranspiration to the atmosphere. However, little care is taken as to the techniques used to excavate bioretention cells, and there is little concern as to the soil-moisture condition during excavation. Certain excavation techniques and soil-moisture conditions create higher levels of compaction which consequently reduce infiltration capacity. Two excavation techniques, the conventional "scoop" method which purposefully smears the underlying soil surface and the "rake" method which uses the teeth of an excavator's bucket to scarify the underlying soil surface, were tested. Field tests were conducted on three soil types sand, loamy sand, and clay under a variety of antecedent soil-moisture conditions. Multiple hydraulic conductivity, surface infiltration, and soil compaction measurements were taken for each excavated condition. In all cases, the rake method of excavation tended to yield more permeable, less compacted soils than the scoop method. The difference of infiltration and hydraulic conductivity between the two excavation techniques was statistically significant p0.05 when tests were conducted in wet soil conditions. Also, the infiltration rate at the clay site was significantly lower p0.05, and the hydraulic conductivity at the sandy site was significantly lower p0.05 when the scoop methodology was used. Based on results of the experiment and because essentially no extra cost is associated with the rake method of excavation, it is recommended over the conventional scoop method. Another recommendation is to excavate under relatively dry soil conditions. The use of the rake method under dry soil conditions is expected to increase long-term exfiltration from bioretention cells.}, number={6}, journal={JOURNAL OF HYDROLOGIC ENGINEERING}, author={Brown, Robert A. and Hunt, William F., III}, year={2010}, month={Jun}, pages={386–394} }
 @inproceedings{winston_hunt_wright_2010, title={Impacts of Roadside Filter Strips, Dry Swales, Wet Swales, and Porous Friction Course on Stormwater Quality}, ISBN={9780784411148}, url={http://dx.doi.org/10.1061/41114(371)308}, DOI={10.1061/41114(371)308}, abstractNote={Because of NPDES regulations, the North Carolina Department of Transportation (NC DOT) is charged with treating stormwater from NC DOT facilities throughout North Carolina. There are thousands of miles of existing right-of-way swales and filter strips across North Carolina. Relatively few roadside swales and filter strips have been tested for water quantity and quality control. Also, no studies exist on swales with wetland characteristics. This paper presents an assessment of dry swale, wetland swale, and filter strip performance along an interstate highway in North Carolina. Four existing right-of-way linear swales along I-40 were monitored to determine their hydrologic and water quality effectiveness. Two different treatments were examined: one dry swale and one which was allowed to establish wetland vegetation and hydrology. This experimental design was replicated once. Also addressed was the impact of the vegetated filter strip between the shoulder and the edge of the swale. Samples have been collected from 17–21 events (depending on the site) and analyzed for TKN, NO2–3-N, TN, NH4-N, Organic-N, TP, and TSS. It should be noted that this section of highway had a porous friction course (PFC) applied, which had an impact on swale and filter strip performance. Mean effluent TN concentrations were lower for the swales with wetland characteristics than the non-wetland swales. No such difference was observed for TP effluent concentrations. TP concentrations measured at the edge-of-highway were low (mean <0.11 mg/L) at all four sites, resulting in poor reduction of TP EMCs by the swales and roadside filter strips. Due to the presence of a PFC on the highway, mean TSS concentrations from the roadway were below 32 mg/L at all four sites. Effluent concentrations of TSS from both the swales and filter strips were higher than edge-of-pavement concentrations. The swales and filter strips did not perform well using traditional concentration reduction metrics for TP and TSS; this was mainly due to the lower sediment-bound pollutant concentrations derived from the porous friction course overlay.}, booktitle={World Environmental and Water Resources Congress 2010}, publisher={American Society of Civil Engineers}, author={Winston, R. J. and Hunt, W. F. and Wright, J. D.}, year={2010}, month={May} }
 @inproceedings{hathaway_hunt_2010, title={Indicator Bacteria Removal by Stormwater BMPs in Coastal North Carolina}, ISBN={9780784411148}, url={http://dx.doi.org/10.1061/41114(371)331}, DOI={10.1061/41114(371)331}, abstractNote={Stormwater runoff is a transport mechanism for indicator bacteria to receiving waters, resulting in an increased risk to public health through consumption of contaminated shellfish or ingestion by swimmers. The resulting economic and public safety concerns are common throughout the United States, particularly in coastal areas. Urban stormwater is commonly treated by stormwater Best Management Practices (BMPs), each of which provides some combination of natural treatment mechanisms and fosters certain environmental conditions. Although BMPs have been studied in detail for many pollutants, there is still a relatively limited understanding of their ability to remove or inactivate indicator bacteria. Geographical differences may also result in varied performance for indicator bacteria removal, as particle association is an important component of indicator bacteria transport and may vary based on soil type. The North Carolina State University Biological and Agricultural Engineering Department monitored 6 stormwater BMPs in Wilmington, NC, to evaluate their efficiency with respect to indicator bacteria removal. The study locations included two bioretention cells, two stormwater wetlands, and two wet ponds. Results indicated that the bioretention cell with a 1-foot media depth did not perform well in comparison to the 2-foot media depth cell. Increased soil water flux in the shallow cell was believed to contribute to these results. Data collected from these studies also indicates that positive removal of indicator bacteria is possible in many types of BMPs; however, removal can be highly variable from BMP to BMP and from storm to storm. Further, stormwater BMPs may promote environments where indicator bacteria can persist, leading to export during some storm events. Finally, even if positive reductions in indicator bacteria are noted, research indicates that achieving effluent concentrations of indicator bacteria consistent with surface water standards may not be possible in many cases.}, booktitle={World Environmental and Water Resources Congress 2010}, publisher={American Society of Civil Engineers}, author={Hathaway, J. M. and Hunt, W. F.}, year={2010}, month={May} }
 @inproceedings{winston_hunt_2010, title={Low Impact Development Benefits of Level Spreader—Vegetative Filter Strip Systems}, ISBN={9780784410998}, url={http://dx.doi.org/10.1061/41099(367)116}, DOI={10.1061/41099(367)116}, abstractNote={Vegetative filter strips (VFS) have been employed to reduce pollutant export from agricultural watersheds for years. In order to enhance the effectiveness of VFSs, level spreaders have been employed to distribute flow evenly across the length of the upslope end of the buffer. During the past decade, level spreaders have been required in nutrient-sensitive watersheds in N.C. to reduce erosion in riparian buffers. An assessment of the performance of four level spreader — vegetative filter strip (LS-VFS) systems was conducted in the Piedmont of North Carolina. At each site, one 7.6 m (25 ft) wide grassed VFS and one 15.2 m (50 ft) wide, half grassed, half forested VFS drained highly impervious watersheds. Monitored parameters included rainfall, inflow to, and outflow from each LS-VFS system. The VFSs promoted infiltration, which resulted in a substantial decrease inflow volume and peak flow rate between the inlet and outlet of the system. To date, 58 storm events have been monitored for hydrology in Louisburg, NC. Mean flow volume was reduced by greater than 40% for both the 7.6 m and 15.2 m VFSs. Reconcentration of surface flow in the VFS was shown to substantially impair filter strip performance. These results show that a LS-VFS system can effectively reduce the hydrologic impacts of impervious surfaces. Twenty-one and twenty-two flow-proportional water quality samples were collected and analyzed for the Apex and Louisburg sites, respectively. Constituents monitored included TKN, NO3+NO2, TN, NH4, Org-N, TP, Ortho-P, PBP, and TSS. All LS-VFS systems studied significantly reduced mean TSS concentrations (p<0.05), with the 7.6 m buffers reducing TSS by at more than 50% and the 15.2 m buffers reducing TSS by more than 65%. Concentrations of TKN, TN, Org-N and NH4-N were significantly reduced (p<0.05) by both 15.2 m VFSs, while results were mixed for the 7.6 m VFSs. Significant pollutant mass reduction was observed (p<0.05) for all nine pollutant species analyzed at the Louisburg site due to infiltration in the VFSs. The effects of VFS length and/or vegetation type are very important for pollutant removal, as effluent pollutant concentrations were lower (with one exception) for the 15.2 m VFSs. Median effluent concentrations for TN and TP for the four LS-VFSs were better than fair water quality benchmarks for the Piedmont of North Carolina, but only met good water quality metrics in one-half of the studied storm events.}, booktitle={Low Impact Development 2010}, publisher={American Society of Civil Engineers}, author={Winston, Ryan J. and Hunt, William F.}, year={2010}, month={Apr} }
 @inproceedings{winston_luell_hunt_2010, title={Mitigating the Effects of Bridge Deck Runoff: A Case Study Using Bioretention and a Bioswale}, ISBN={9780784411148}, url={http://dx.doi.org/10.1061/41114(371)307}, DOI={10.1061/41114(371)307}, abstractNote={Stormwater runoff from roadways is a major source of surface water pollution in North Carolina. The North Carolina Department of Transportation (NCDOT) is tasked with implementing stormwater BMPs alongside linear highways. NCDOT has specific interest in runoff from bridge decks, which is often discharged through drainage holes in the deck directly to the stream below. NCDOT needs to determine optimal retrofit stormwater BMPs associated with bridge decks. Two bioretention cells and a bioswale were constructed in the easement of a bridge deck on I-540 at Mango Creek. One bioretention cell was adequately sized based on current North Carolina design guidance, while the other was undersized by one-half. Undersized bioretention cells could often be used in retrofit situations; therefore, it is important to understand how an undersized bioretention cell performs with respect to hydrology and water quality. Both bioretention cells employed 0.9 m (3 ft) of fill media, and had an internal water storage layer (IWS) of 0.6 m (2 ft). The swale was designed to convey the 2-year storm event without overtopping and had a surface area to length ratio of 130 m2/m. Runoff was piped from the northbound and southbound lanes to the bioretention cells and swale, respectively. Data collection began in October 2009. Weirs and stage recorders were used to monitor inflow to and outflow from each BMP. Flow-proportional, composite water quality samples were obtained at the inlet and outlet of each BMP. Monitored water quality parameters included TKN, NO2–3-N, NH4-N, TN, TP, and TSS. In terms of TN, TP, and TSS concentrations, bridge deck runoff quality at Mango Creek was at least 50% cleaner than at other bridge decks studied in North Carolina, Louisiana, and China. The undersized and standard bioretention cells produced similar effluent concentrations for nutrients and TSS; however, the standard bioretention cell reduced runoff volumes from events less than 2.5cm to a much greater extent (86% versus 49%). The bioswale did not reduce runoff volumes, and was ineffective in reducing pollutant concentrations.}, booktitle={World Environmental and Water Resources Congress 2010}, publisher={American Society of Civil Engineers}, author={Winston, R. J. and Luell, S. K. and Hunt, W. F.}, year={2010}, month={May} }
 @inproceedings{brown_hunt_skaggs_2010, title={Modeling Bioretention Hydrology with DRAINMOD}, ISBN={9780784410998}, url={http://dx.doi.org/10.1061/41099(367)39}, DOI={10.1061/41099(367)39}, abstractNote={It has been documented that bioretention cells are an effective low impact development (LID) stormwater practice to remove nitrogen, phosphorus, and other pollutants at high rates, as well as to restore a site's pre-developed hydrology. However, hydrologic performance has varied greatly in past field studies because of the impact of underlying soils, physiographic regions, drainage configuration, and media depth. Development of a long-term hydrologic model that generates an annual water balance is needed to more accurately describe hydrologic performance to predict pollutant loads and to determine whether a site meets LID hydrology criteria. The only models available are either unable to run continuous simulations or do not accurately model underdrain flow for typical designs of bioretention cells. DRAINMOD, a widely accepted long-term agricultural drainage model, is being used to predict bioretention hydrology. The concepts of water movement in bioretention cells are very similar to agricultural fields with drainage pipes, so many bioretention design specifications correspond directly to DRAINMOD inputs. As a result, calibration of DRAINMOD to model bioretention hydrology is currently underway. Detailed hydrologic data have been specifically collected from two field sites over the past 24 months to calibrate the model. Additional hydrology data are available from at least 10 other bioretention cells across NC to validate the model. DRAINMOD is also unique from other bioretention models in that it accounts for evapotranspiration (ET), and the controlling factor in DRAINMOD is the drainage configuration which employs the Richards Equation. The model can be used on an hour-by-hour basis for long periods of climatological records (e.g. 50 years). Hydrologic outputs from the model include: volume of runoff, overflow, drainage, exfiltration, and ET. These outputs will allow users to examine the water balance to discern a most suitable design based on varying design configurations.}, booktitle={Low Impact Development 2010}, publisher={American Society of Civil Engineers}, author={Brown, Robert A. and Hunt, William F. and Skaggs, R. Wayne}, year={2010}, month={Apr} }
 @article{jones_hunt_2010, title={Performance of rainwater harvesting systems in the southeastern United States}, volume={54}, ISSN={["1879-0658"]}, DOI={10.1016/j.resconrec.2009.11.002}, abstractNote={Recent severe droughts, concerns over the environmental impact of stormwater runoff and increased water demands have generated interest in rainwater harvesting systems in humid, well developed regions, such as the southeastern United States. In order to evaluate the use of rainwater harvesting systems in this region, a monitoring study was conducted at three rainwater cisterns in North Carolina, a computer model was developed to simulate system performance, and simulations were conducted for 208 l rain barrels and larger cisterns. Results of the monitoring study showed that the rainwater harvesting systems were underutilized, which was suspected to result from poor estimation of water usage and public perception of the harvested rainwater. The computer model simulated system performance by evaluating a water balance using historical rainfall data and anticipated usage. Simulation results showed that a rain barrel was frequently depleted when used to meet household irrigation demands and overflowed during most rainfall events. Simulations also illustrated the improved performance of large systems while providing an indication of diminishing returns for increased cistern capacity.}, number={10}, journal={RESOURCES CONSERVATION AND RECYCLING}, author={Jones, Matthew P. and Hunt, William F.}, year={2010}, month={Aug}, pages={623–629} }
 @inproceedings{winston_luell_hunt_2010, title={Retrofitting with Bioretention and a Bioswale to Treat Bridge Deck Stormwater Runoff}, ISBN={9780784411483}, url={http://dx.doi.org/10.1061/41148(389)13}, DOI={10.1061/41148(389)13}, abstractNote={Stormwater runoff from roadways is a source of surface water pollution in North Carolina. The North Carolina Department of Transportation (NCDOT) is required to implement stormwater BMPs in the linear environment. NCDOT has specific interest in runoff from bridge decks, which is often discharged through drainage holes in the deck directly to the stream below. This research focuses on retrofit stormwater BMPs for bridge deck runoff management. Two bioretention cells and a bioswale were constructed in the easement of a bridge deck on I-540 at Mango Creek. One bioretention cell was adequately sized based on current North Carolina design guidance, while the other was undersized by one-half. Undersized bioretention cells could often be used in retrofit situations; therefore, it is important to understand how an undersized bioretention cell performs with respect to hydrology and water quality. Both bioretention cells employed 0.9 m (3 ft) of fill media, and had an internal water storage layer (IWS) of 0.6 m (2 ft). The bioswale was designed to convey the 2-year storm event. Runoff was piped from the northbound and southbound lanes to the bioretention cells and bioswale, respectively. Data collection began in October 2009. Weirs and stage recorders were used to monitor inflow to and outflow from each BMP. Flow-proportional, composite water quality samples were obtained at the inlet and outlet of each BMP. Monitored water quality parameters include TKN, NO2-3-N, NH4-N, TN, TP, TSS, Cu, Zn, and Pb. For small storms (those with less than 1 in [2.5 cm] rainfall depth), flow volume reductions for the standard and undersized bioretention cells were 50% and 27%, respectively. This shows the hydrologic importance of sizing bioretention cells appropriately when space is available. Average concentrations of TN (0.74 mg/L), TP (0.12 mg/L), and TSS (31 mg/L) from the bridge decks were relatively low when compared to other highways in North Carolina. Median effluent concentrations for the standard bioretention cell were lower than those for the undersized bioretention cell for all nutrient forms and sediment. Pollutant loads of TN, TP, and TSS were reduced to a much greater extent by the standard bioretention cell due to improved volumetric runoff reductions. The bioswale had similar influent and effluent concentrations for TN, TP, and TSS. Reductions in flow volume for the bioswale were not observed, resulting in poor pollutant load reduction.}, booktitle={Green Streets and Highways 2010}, publisher={American Society of Civil Engineers}, author={Winston, R. J. and Luell, S. K. and Hunt, W. F.}, year={2010}, month={Nov} }
 @article{hunt_hathaway_winston_jadlocki_2010, title={Runoff Volume Reduction by a Level Spreader-Vegetated Filter Strip System in Suburban Charlotte, NC}, volume={15}, ISSN={["1943-5584"]}, DOI={10.1061/(asce)he.1943-5584.0000160}, abstractNote={The premise of low impact development (LID) is to reduce runoff volumes while simultaneously matching target (often predevelopment) infiltration and evapotranspiration volumes. Many structural practices used in LID, such as bioretention, infiltration trenches, and permeable pavement, require a seasonally high water table (SHWT) to be 1–2 m from the surface. Conversely, level spreader–vegetated filter strip systems can be implemented in locations where a SHWT would restrict the use of other practices. A 19.4 m long reinforced concrete level spreader upslope of a 900  m2 mixed grass/weed vegetated filter strip was monitored for runoff reduction for 23 precipitation events from November 2005 to January 2007 in Charlotte, N.C. The practice treated runoff from a 0.87 ha (2.15 acre) residential watershed. Of the 23 monitored events, only 3 produced outflow. All events which produced outflow exceeded 40 mm (1.6 in.) of precipitation. Cumulative volume reduction associated with the events was 85%, which compares ...}, number={6}, journal={JOURNAL OF HYDROLOGIC ENGINEERING}, author={Hunt, W. F. and Hathaway, J. M. and Winston, R. J. and Jadlocki, S. J.}, year={2010}, month={Jun}, pages={499–503} }
 @article{collins_hunt_hathaway_2010, title={Side-by-Side Comparison of Nitrogen Species Removal for Four Types of Permeable Pavement and Standard Asphalt in Eastern North Carolina}, volume={15}, ISSN={["1943-5584"]}, DOI={10.1061/(asce)he.1943-5584.0000139}, abstractNote={A 1 year-old parking lot in eastern North Carolina consisting of four types of side-by-side permeable pavement and standard asphalt was monitored from January 2007 to July 2007 for water quality differences among pavement types. The four permeable sections were pervious concrete (PC), two different types of permeable interlocking concrete pavement (PICP) with small-sized aggregate in the joints and having 12.9% (PICP1) and 8.5% (PICP2) open surface area, and concrete grid pavers (CGP) filled with sand. The site was located in poorly drained soils, and all permeable sections were underlain by a crushed stone base with a perforated pipe underdrain. Composite, flow-weighted samples of atmospheric deposition and asphalt runoff were compared to those of permeable pavement subsurface drainage for pH, TN, NO2,3 –N , TKN, NH4 –N , and ON concentrations and loads. All pavements buffered acidic rainfall pH ( p<0.01 ) . The pH of permeable pavement subsurface drainage was higher than that of asphalt runoff ( p<0.01 ...}, number={6}, journal={JOURNAL OF HYDROLOGIC ENGINEERING}, author={Collins, Kelly A. and Hunt, William F. and Hathaway, Jon M.}, year={2010}, month={Jun}, pages={512–521} }
 @article{hathaway_hunt_simmons_2010, title={Statistical Evaluation of Factors Affecting Indicator Bacteria in Urban Storm-Water Runoff}, volume={136}, ISSN={0733-9372 1943-7870}, url={http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0000278}, DOI={10.1061/(ASCE)EE.1943-7870.0000278}, abstractNote={An urban watershed in Raleigh, North Carolina, was monitored for indicator bacteria during 20 rain events. Results showed elevated levels of E. coli, enterococci, and fecal coliform. Samples were compared based on seasonality and were found to be statistically different ( p<0.05 ) , with pairwise comparisons indicating significantly lower concentrations of E. coli and fecal coliform during the winter ( p<0.05 ) . Enterococci concentrations were substantially lower in the winter and fall, but no significant differences were found between seasons during pairwise comparisons ( p<0.05 ) . Correlation analyses showed multiple significant relationships between antecedent climate parameters, flow characteristics, and indicator bacteria concentrations. More detailed multiple linear regression yielded explanatory variables related to antecedent climate conditions. Variables were generally related to temperature and moisture conditions in the atmosphere and soil. The results of this study show indicator bacteria co...}, number={12}, journal={Journal of Environmental Engineering}, publisher={American Society of Civil Engineers (ASCE)}, author={Hathaway, J. M. and Hunt, W. F. and Simmons, O. D., III}, year={2010}, month={Dec}, pages={1360–1368} }
 @inproceedings{lord_hunt_2010, title={Stormwater BMP Inspection and Maintenance Program in North Carolina—A 3 Year Update}, ISBN={9780784410998}, url={http://dx.doi.org/10.1061/41099(367)54}, DOI={10.1061/41099(367)54}, abstractNote={Stormwater BMPs are being installed across the United States and studies show they are not being properly inspected and maintained. If not properly maintained, stormwater BMPs will not perform as intended or fail, but little guidance or training on maintenance and inspection procedures is available. The North Carolina State University Cooperative Extension Service developed a 1.5 day Stormwater BMP Inspection and Maintenance program in 2007 that has trained and certified more than 1250 local government officials, design professionals, and landscape maintenance practitioners from across the United States. The course consists of 12 modules that range from stormwater regulations to parking lot BMPs. A learner feedback loop has been incorporated into ongoing development of the course and information is being gathered about whom does maintenance, how it is done, and how often it is performed. Upon passing an exam, the Extension Service certifies an individual for 3 years, when a 4 hour recertification class is being offered. To date, approximately 10 cities and counties in North Carolina are requiring certification for anyone who inspects or maintains stormwater BMPs.}, booktitle={Low Impact Development 2010}, publisher={American Society of Civil Engineers}, author={Lord, William G. and Hunt, William F.}, year={2010}, month={Apr} }
 @inproceedings{smith_hunt_2010, title={Structural/Hydrologic Design and Maintenance of Permeable Interlocking Concrete Pavement}, ISBN={9780784410998}, url={http://dx.doi.org/10.1061/41099(367)129}, DOI={10.1061/41099(367)129}, abstractNote={Permeable interlocking concrete pavements (PICP) combine stormwater infiltration, detention and a riding surface for vehicles into one location. These pavements rely on an open-graded crushed stone base for storage, infiltration and vehicular support. Much research has been conducted on the hydrologic and water quality aspects. State and municipal BMP (best management practices) and LID (low impact development) manuals have incorporated design guidelines developed from university research, industry guidelines and experience by various agencies, project owners, civil engineers and contractors. This paper integrates hydrological and structural design for PICP for potential use in the emerging ASCE guidelines for permeable pavement. Hydrological analysis determines if the volume of water from user-selected rainfall events can be stored and released by the pavement base. Designer-selected parameters determine how much water infiltrates the soil subgrade and/or is carried away by subdrains. Structural capacity for vehicular loads is determined using PICP industry design charts or the American Association of State Highway and Transportation Officials (AASHTO) 1993 structural design method. This paper includes design examples using these methodologies with an example using design software. The paper includes input design considerations as well as outputs for stormwater drainage and pavement design. In addition, recent experience is summarized on surface cleaning and surface repair.}, booktitle={Low Impact Development 2010}, publisher={American Society of Civil Engineers}, author={Smith, David R. and Hunt, William F.}, year={2010}, month={Apr} }
 @inproceedings{smith_hunt_2010, title={Structural/Hydrologic Design and Maintenance of Permeable Interlocking Concrete Pavement}, ISBN={9780784411483}, url={http://dx.doi.org/10.1061/41148(389)30}, DOI={10.1061/41148(389)30}, abstractNote={Permeable interlocking concrete pavements (PICP) combine stormwater infiltration, detention and a riding surface for vehicles into one location. These pavements rely on an open-graded crushed stone base for storage, infiltration and vehicular support. Much research has been conducted on the hydrologic and water quality aspects. State and municipal best management practices (BMP) and low impact development (LID) manuals have incorporated design guidelines developed from university research, industry guidelines and experience by various agencies, project owners, civil engineers and contractors. This paper integrates hydrological and structural design for PICP for potential use in the emerging American Society of Civil Engineers (ASCE) guidelines for permeable pavement. Hydrological analysis determines if the volume of water from user-selected rainfall events can be stored and released by the pavement base. Designer-selected parameters determine how much water infiltrates the soil subgrade and/or is carried away by subdrains. Structural capacity for vehicular loads is determined using PICP industry design charts or the American Association of State Highway and Transportation Officials (AASHTO) 1993 structural design method. This paper includes design examples using these methodologies with an example using design software. The paper includes input design considerations as well as outputs for stormwater drainage and pavement design. In addition, recent experience is summarized on surface cleaning and surface repair.}, booktitle={Green Streets and Highways 2010}, publisher={American Society of Civil Engineers}, author={Smith, David R. and Hunt, William F.}, year={2010}, month={Nov} }
 @inproceedings{debusk_hunt_sydorovych_2010, title={Watershed Retrofit and Management Evaluation for Urban Stormwater Management Systems in North Carolina}, ISBN={9780784411148}, url={http://dx.doi.org/10.1061/41114(371)398}, DOI={10.1061/41114(371)398}, abstractNote={In response to water quality concerns in the Jordan Lake Reservoir and state and federal mandates, several cities in North Carolina are being required for the first time to reduce nutrient loads in stormwater from previously developed lands, that is, install retrofits. It is anticipated that similar requirements will become necessary for other urban areas in North Carolina. The goal of this study is to evaluate the feasibility of alternative approaches to stormwater management for existing developments within North Carolina cities. Geographic coverage of the study included a portion of the New Hope Creek watershed, located within the City of Durham in central North Carolina. The watershed was analyzed to identify potential retrofit opportunities that could be implemented to reduce pollutant loadings entering New Hope Creek and, ultimately, Jordan Lake. Current pollutant loadings generated by the watershed, as well as reductions in annual loadings of total suspended solids, total nitrogen and total phosphorus that could be achieved by implementing the identified retrofits, were estimated. Trends and relationships between land use type and the quantity and type of retrofit opportunities were identified and conclusions were drawn as to the most appropriate types of retrofits for certain land uses.}, booktitle={World Environmental and Water Resources Congress 2010}, publisher={American Society of Civil Engineers}, author={DeBusk, Kathy and Hunt, Bill and Sydorovych, Olha}, year={2010}, month={May} }
 @inproceedings{hunt, iii_2010, title={Working with Regulators to Change Permeable Pavements Acceptance}, ISBN={9780784410998}, url={http://dx.doi.org/10.1061/41099(367)110}, DOI={10.1061/41099(367)110}, abstractNote={Starting in 1999, North Carolina State University faculty began research on permeable pavement used to infiltrate stormwater runoff, or permeable pavement. NC State conducted several studies from 1999 to 2005, all of which repeatedly showed positive performance for runoff reduction. Faculty at NC State cooperated with regulators at the North Carolina Department of Environment and Natural Resources (NC DENR) and eventually helped persuade the regulators to accept permeable pavement as a stormwater best management practice in 2006. Permeable pavement's initial "approval" was confined to the eastern, and sandier soil region, one-third of the state of North Carolina. Subsequent to the initial allowance, faculty at NC State further cooperated with staff of State Senator Marc Basnight who passed a law requiring the use of permeable pavement, or an acceptable alternative, in parking lots across the state of North Carolina. The NC Department of Transportation (DOT) has since been required to evaluate the use of permeable pavement for every sidewalk in NC DOT right-of-way statewide. This loosened the restriction for use of permeable pavement for only sandy in-situ soils. Due to the change in state policy, certain communities have embraced the use of permeable pavement, and the implementation of the product has increased substantially. One of the main reasons for this was the NC DENR's treating of permeable pavement as a mostly permeable (and partially impermeable) surface. The relationship of a university working hand-in-hand with regulators has proven very beneficial for the use of permeable pavement.}, booktitle={Low Impact Development 2010}, publisher={American Society of Civil Engineers}, author={Hunt, III, William F.}, year={2010}, month={Apr} }
 @inproceedings{winston_hunt_2009, title={A Level Spreader — Vegetated Buffer System for Urban Stormwater Management}, ISBN={9780784410363}, url={http://dx.doi.org/10.1061/41036(342)75}, DOI={10.1061/41036(342)75}, abstractNote={Vegetated filter strips (VFS) have been used to remove pollutants from contributing agricultural watersheds for decades. In order to improve effectiveness of vegetated buffers, level spreaders have been employed to distribute flow evenly across the length of the upstream end of the buffer. In North Carolina, level spreader- VFS systems are now gaining acceptance as a stormwater BMP for urbanized watersheds, as it promotes infiltration and reduces impervious surfaces, two tenets of Low Impact Development. A field study of four level spreader — vegetated filter strip systems was conducted at two urban watersheds in Louisburg and Apex, NC. At each site, stormwater was routed proportionately over two 13 ft long level spreaders, one draining to a 25 ft wide grassed buffer, the other to a 50 ft wide, half grassed, half forested buffer. Flow rates and flow volumes were measured at the inlet and outlets of the system. Composite, flow-weighted water quality samples were collected at the inlet and outlet of the system and analyzed for TKN, NO 3 +NO 2 , TN, NH 3 TP, Orthophosphate, and TSS. The buffers promoted infiltration, which resulted in a substantial decrease in flow volume and peak flow rate between the inlet and outlet of the system. To date, 46 storm events have been monitored for hydrology in Louisburg, NC. Flow volume was reduced by an average of 83% and 80% for the 25 ft and 50 ft wide buffers, respectively. These buffers also reduced peak flow rate by an average of 86% and 83%, respectively. These results show that a level spreader — vegetated filter strip system can effectively reduce the hydrologic impacts of impervious surfaces. Water quality monitoring has been ongoing since March, 2008, with 19 and 20 storms monitored for Apex and Louisburg, respectively. Reductions in event mean concentrations for all buffer treatments occurred for TKN, TN, and TSS, while the other pollutants studied had mixed results. Because of the large reduction in volume due to infiltration, these BMPs provide a large reduction in mass of pollutants. The median percent mass removal for the Louisburg buffers was greater than 74% for all but one water quality constituent studied. A level spreader is relatively (1) easy to install, (2) inexpensive, and (3) requires little maintenance. Carefully selected and designed level spreader — vegetated buffer systems can be an effective method of controlling stormwater flow and its associated pollutants in small urban watersheds.}, booktitle={World Environmental and Water Resources Congress 2009}, publisher={American Society of Civil Engineers}, author={Winston, Ryan J. and Hunt, William F.}, year={2009}, month={May} }
 @inproceedings{hathaway_hunt_2009, title={An Evaluation of Stormwater Wetlands in Series}, ISBN={9780784410363}, url={http://dx.doi.org/10.1061/41036(342)82}, DOI={10.1061/41036(342)82}, abstractNote={Retrofit BMPs are an important tool for achieving water quality goals in urban watersheds, providing treatment to areas not originally developed with stormwater management practices. One such BMP was installed and monitored in Mooresville, N.C. The system includes three wetlands built 'in-series' to treat runoff from a highly impervious 30 acre watershed. The configuration of the wetlands allowed monitoring of water quality parameters at the outlet of each of the three stormwater wetlands. The results of this study indicate that water quality improvement for a number of pollutants experiences diminishing returns as it passes through the three wetland cells. For total suspended solids (TSS), approximately 95% of the total concentration reduction took place in the first wetland cell despite it only comprising 60% of the total surface area of the system. Analysis of the effluent concentrations of the first wetland cell indicates that undersized wetlands (roughly 1.5% of the contributing watershed in this case) may still contribute to water quality improvements in urban watersheds. Thus, retrofit BMPs may be desirable even in circumstances when they cannot be sized appropriately for the contributing watershed.}, booktitle={World Environmental and Water Resources Congress 2009}, publisher={American Society of Civil Engineers}, author={Hathaway, J. M. and Hunt, W. F.}, year={2009}, month={May} }
 @article{passeport_hunt_2009, title={Asphalt parking lot runoff nutrient characterization for eight sites in North Carolina, USA}, volume={14}, DOI={10.1061/(ASCE)1084-0699(2009)14:4(352)}, abstractNote={The objectives of this study were to characterize asphalt parking lot runoff quality and determine factors influencing nutrient concentrations and loads. Event mean concentrations (EMCs) and loads were measured from eight asphalt parking lots in North Carolina using automated flow meters and rain gauges. The number of water quality samples collected varied from 11 to 26 per site. EMCs and loads were statistically analyzed for six nutrient forms: total nitrogen, total Kjeldahl nitrogen, ammonia-nitrogen, nitrate-nitrogen, total phosphorus, and ortho-phosphate. The mean EMCs (in mg/L) were 1.57, 1.19, 0.32, 0.36, 0.19 and 0.07, respectively. Nitrogen species’ concentrations were slightly lower than those from highway runoff found in the literature; whereas, phosphorus EMCs were similar to those in highway runoff. Current load prediction models, generally based on highway or roadway nutrient concentrations, are therefore expected to over-estimate nitrogen loads from asphalt parking lots. Spring and summer pr...}, number={4}, journal={Journal of Hydrologic Engineering}, author={Passeport, E. and Hunt, W. F.}, year={2009}, pages={352–361} }
 @article{jones_hunt_2009, title={Bioretention Impact on Runoff Temperature in Trout Sensitive Waters}, volume={135}, ISSN={["1943-7870"]}, DOI={10.1061/(asce)ee.1943-7870.0000022}, abstractNote={A study was conducted in western North Carolina, along the southeastern extent of the U.S. trout populations, to examine the effect of bioretention areas on runoff temperature. Four bioretention areas were monitored during the summers of 2006 and 2007. It was found that smaller bioretention areas, with respect to the size of their contributing watershed, were able to significantly reduce both maximum and median water temperatures between the inlet and outlet. The proportionately larger bioretention areas were only able to significantly reduce maximum water temperatures between the inlet and outlet; however, these systems showed evidence of substantial reductions in outflow quantity, effectively reducing the thermal impact. Despite temperature reductions, effluent temperatures still posed a potential threat to coldwater streams during the peak summer months. During the summer months, effluent temperatures were generally coolest at the greatest soil depths, supporting evidence of an optimum drain depth between 90 and 120 cm. The ability of bioretention areas to reduce storm-water temperature and flows supports their application to reduce the thermal impacts of urban storm-water runoff.}, number={8}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING}, author={Jones, Matthew P. and Hunt, William F.}, year={2009}, month={Aug}, pages={577–585} }
 @article{davis_hunt_traver_clar_2009, title={Bioretention technology: Overview of current practice and future needs}, volume={135}, DOI={10.1061/(asce)0733-9372(2009)135:3(109)}, abstractNote={Bioretention, or variations such as bioinfiltration and rain gardens, has become one of the most frequently used storm-water management tools in urbanized watersheds. Incorporating both filtration and infiltration, initial research into bioretention has shown that these facilities substantially reduce runoff volumes and peak flows. Low impact development, which has a goal of modifying postdevel- opment hydrology to more closely mimic that of predevelopment, is a driver for the use of bioretention in many parts of the country. Research over the past decade has shown that bioretention effluent loads are low for suspended solids, nutrients, hydrocarbons, and heavy metals. Pollutant removal mechanisms include filtration, adsorption, and possibly biological treatment. Limited research suggests that bioretention can effectively manage other pollutants, such as pathogenic bacteria and thermal pollution, as well. Reductions in pollutant load result from the combination of concentration reduction and runoff volume attenuation, linking water quality and hydrologic perfor- mance. Nonetheless, many design questions persist for this practice, such as maximum pooling bowl depth, minimum fill media depth, fill media composition and configuration, underdrain configuration, pretreatment options, and vegetation selection. Moreover, the exact nature and impact of bioretention maintenance is still evolving, which will dictate long-term performance and life-cycle costs. Bioretention usage will grow as design guidance matures as a result of continued research and application.}, number={3}, journal={Journal of Environmental Engineering (New York, N.Y.)}, author={Davis, A. P. and Hunt, W. F. and Traver, R. G. and Clar, M.}, year={2009}, pages={109–117} }
 @inproceedings{brown_hunt_davis_traver_olszewski_2009, title={Bioretention/Bioinfiltration Performance in the Mid-Atlantic}, ISBN={9780784410363}, url={http://dx.doi.org/10.1061/41036(342)90}, DOI={10.1061/41036(342)90}, abstractNote={Researchers in Maryland, North Carolina, and Pennsylvania have been conducting parallel bioretention/bioinfiltration research since fall 2007. Various designs have been tested including those that rely on underdrains, have internal water storage (IWS) layers, or are underdrain-free. The cells provide a range of watershed practice size ratios and employ a variety of land covers. Researchers are pooling water quantity and quality data to help create new design standards. Initial results from the shared data will be presented, with specific attention to bioretention design parameters that control flow modification and water quality improvement. Two bioretention cells of varying vegetative cover are being monitored in Rocky Mount, NC. This site is located in the upper coastal plain with sandy in-situ soils. These cells were designed with a 0.9 m media depth and a 0.6 m deep internal water storage (IWS) layer. Another bioretention cell is being monitored in Silver Spring, MD. It was constructed with a 0.9 m media depth and a 0.3 m pooling depth. Finally, there are two bioinfiltration cells being monitored in Villanova, PA. The first is the "Traffic Island" bioinfiltration cell, which has been monitored since 2003. The bowl is only designed for 1.2 cm over the impervious surface, yet overflow rarely occurs for events less than 5.1 cm. The site had groundwater wells installed in 2007 and is the subject of an ongoing study on the groundwater effects. The second site has only been monitored for approximately six months. Cumulatively, the four bioretention cells extensively examined have dramatically reduced outflow volumes, completely assimilating all events less than 1.2 cm — and in some designs much greater events. By aggregating the data, runoff reduction by bioretention can be profound.}, booktitle={World Environmental and Water Resources Congress 2009}, publisher={American Society of Civil Engineers}, author={Brown, R. A. and Hunt, W. F. and Davis, A. P. and Traver, R. G. and Olszewski, J. M.}, year={2009}, month={May} }
 @inproceedings{roseen_carrasco_cheng_hunt_johnston_mailloux_stein_williams_2009, title={Data Reporting Guidelines for Certification of Manufactured Stormwater BMPs: Part II}, ISBN={9780784410363}, url={http://dx.doi.org/10.1061/41036(342)100}, DOI={10.1061/41036(342)100}, abstractNote={Data Reporting guidelines presented here were developed as part of the ASCE/EWRI Task Committee on Guidelines for Certification of Manufactured Stormwater BMPs. This work is the collaboration of the Stormwater Infrastructure Committee of EWRI's Water, Wastewater, and Stormwater Council (WWSC) and the Wet Weather Flow Technology Committee of the Urban Water Resources Research Council (UWRRC). These guidelines were developed by review of the major manufactured treatment device certification protocol requirements drawing primarily from the Technology Assessment Protocol-Ecology (TAPE) and the Technology Assessment Reciprocity Partnership (TARP). These reporting guidelines have been broadened to support the International Stormwater Best Management Practices (BMP) Database. With the increasing need for the field testing of proprietary devices comes the importance of consistent data reporting guidelines to be used when reporting to regulatory agencies or designers. The need for standardized reporting is underscored by the tremendous impact the range of testing factors can have upon testing results. These factors include the testing environment, experimental design, testing methodologies, statistical analysis, and data presentation. The need for consistency is underscored by the complex influence these factors have upon performance results. A clear and consistent data reporting approach can ensure that these biases are minimized, well understood, and that representative field testing can be effectively evaluated by the regulatory agency. A consistent reporting format is also needed to aid vendors to efficiently navigate the complicated application process for device certification. Finally, an independent third-party is needed to either conduct or review the testing to ensure testing impartiality. The committee membership includes stakeholders from the regulatory, academic, manufacturing, and design communities.}, booktitle={World Environmental and Water Resources Congress 2009}, publisher={American Society of Civil Engineers}, author={Roseen, Robert M. and Carrasco, Ernie and Cheng, Yuan and Hunt, Bill and Johnston, Charlene and Mailloux, Jim and Stein, Walt and Williams, Tim}, year={2009}, month={May} }
 @inproceedings{jones_hunt_2009, title={Effect of Bioretention on Runoff Temperature in Trout Sensitive Regions}, ISBN={9780784410363}, url={http://dx.doi.org/10.1061/41036(342)156}, DOI={10.1061/41036(342)156}, abstractNote={Although it has been established that thermal pollution from urban stormwater can negatively impact the aquatic ecosystem, there are few mechanisms available to reduce the temperature or urban stormwater runoff. A monitoring study was conducted at 4 bioretention areas in western North Carolina, located along the southeastern extent of United States trout populations, to examine the effect these systems have on runoff temperature and identify any design criteria pertinent to temperature reduction. Median runoff temperatures leaving the pavement surfaces, based on storm events, exceeded the 21°C upper avoidance temperature of trout at all sites during the months of June through September. Of the bioretention areas studied, the two systems that covered an area smaller than 10% of their contributing watershed were able to significantly (p<0.01) reduce both maximum and median storm temperatures between the inlet and outlet. At the two bioretention areas that were larger than 10% of their contributing watershed area, maximum effluent temperatures were significantly (p<0.01) cooler than influent temperatures; however, there was no significant (p<0.05) difference between median influent and effluent temperatures. Despite reductions in temperature, effluent temperatures were not significantly (p<0.05) cooler than the upper avoidance temperature for trout at any of the monitoring locations. There was evidence that substantial reductions in runoff volume occurred at all bioretention areas, especially the systems that were larger than 10% of their contributing watershed. Overall, monitoring results indicated that bioretention areas served as effective treatment mechanisms for reducing, but not eliminating, the thermal impacts associated with urban stormwater runoff.}, booktitle={World Environmental and Water Resources Congress 2009}, publisher={American Society of Civil Engineers}, author={Jones, Matthew and Hunt, William F.}, year={2009}, month={May} }
 @inproceedings{brown_hunt_2009, title={Effects of Media Depth on Bioretention Performance in the Upper Coastal Plain of North Carolina and Bioretention Construction Impacts Study}, ISBN={9780784410363}, url={http://dx.doi.org/10.1061/41036(342)104}, DOI={10.1061/41036(342)104}, abstractNote={Bioretention is a principal low impact development (LID) practice. This paper examines two critical questions associated with bioretention design and construction. First, fill media is perhaps the major cost in constructing bioretention cells, so shallower media depths would be preferred, were they to work as well as deeper media systems. Two sets of bioretention cells of varying media depths in the upper coastal plain of North Carolina have been monitored since April 2008. They treat an impervious asphalt parking lot watershed in Nashville, NC. The bioretention cells were constructed with media depths of 0.6 and 0.9 m. Performance is being measured with respect to hydrology and water quality. Data show the deeper media depths meet the LID hydrology goal of volume reduction more frequently (35% compared to 9% of 45 events monitored). The second question examines how bioretention cells are excavated. Two excavation techniques, the conventional "scoop" method which purposefully smears the underlying soil surface and the "rake" method which uses the teeth of an excavator's bucket to scarify the underlying soil surface, were tested. Field tests were conducted on three soil types (sand, loamy sand, and clay) and under a variety of antecedent soil moisture conditions. Saturated hydraulic conductivity, surface infiltration, and soil compaction were measured for each excavated condition. In all cases, the rake method of excavation yielded more permeable, less compacted soils than the scoop method. The difference of infiltration and hydraulic conductivity between the two excavation techniques was statistically significant (p<0.05) when tests were conducted in wet soil conditions. Also, the infiltration rate at the clay site was significantly lower (p<0.05), and the hydraulic conductivity at the sandy site was significantly lower (p<0.05), when the scoop methodology was used. Based on results of this experiment and because there is essentially no extra cost associated with the rake method of excavating bioretention cells, the rake method of excavation is recommended over the conventional scoop method. The use of the rake method is expected to increase long term exfiltration from bioretention cells.}, booktitle={World Environmental and Water Resources Congress 2009}, publisher={American Society of Civil Engineers}, author={Brown, R. A. and Hunt, W. F.}, year={2009}, month={May} }
 @inproceedings{hathaway_hunt_wright_jadlocki_2009, title={Field Evaluation of Indicator Bacteria Removal by Stormwater BMPs in North Carolina}, ISBN={9780784410363}, url={http://dx.doi.org/10.1061/41036(342)112}, DOI={10.1061/41036(342)112}, abstractNote={In the United States Environmental Protection Agency's National Water Quality Inventory in 2000, 13% of the river and stream miles that were surveyed were impaired by pathogen indicator bacteria (USEPA 2002). Stormwater runoff is a transport mechanism for indicator bacteria to receiving waters, resulting in an increased risk to public health through consumption of contaminated shellfish or ingestion by swimmers. Urban stormwater is commonly treated by stormwater Best Management Practices (BMPs), each of which provides some combination of natural treatment mechanisms and fosters certain environmental conditions. Although BMPs have been studied in detail for many pollutants, little peer-reviewed literature is available which documents their ability to remove or inactivate indicator bacteria. The North Carolina State University Department of Biological and Agricultural Engineering evaluated 10 stormwater BMPs in Charlotte and Wilmington, NC, to evaluate their efficiency with respect to indicator bacteria removal. The study practices included two bioretention cells, four stormwater wetlands, two wet ponds, and two dry detention areas. Data collected from these studies indicates that positive removal of indicator bacteria is possible in many types of BMPs; however, removal can be highly variable from practice to practice. Further, stormwater BMPs may foster environments where indicator bacteria can persist, becoming sources of indicator bacteria. Finally, even if positive reductions in indicator bacteria are noted, research indicates that achieving effluent concentrations of indicator bacteria consistent with USEPA standards may be difficult with many types of BMPs.}, booktitle={World Environmental and Water Resources Congress 2009}, publisher={American Society of Civil Engineers}, author={Hathaway, J. M. and Hunt, W. F. and Wright, J. D. and Jadlocki, S. J.}, year={2009}, month={May} }
 @article{passeport_hunt_line_smith_brown_2009, title={Field Study of the Ability of Two Grassed Bioretention Cells to Reduce Storm-Water Runoff Pollution}, volume={135}, ISSN={["1943-4774"]}, DOI={10.1061/(ASCE)IR.1943-4774.0000006}, abstractNote={Two grassed bioretention cells including internal storage zones (ISZs) were monitored for 16 months in central North Carolina. Each cell had a surface area of 106 m2 and fill media depths were 0.75 and 1.05 m for the north (North) and the south (South) cells, respectively. Asphalt parking lot inflow and outflows were analyzed for nitrogen and phosphorus forms and fecal coliform (FC). Outflow volumes and peak flows for individual storms were generally less than those of inflow. Overall, except for N O2,3 –N , effluent nitrogen species event mean concentrations (EMCs) and loads were significantly (α=0.05) lower than those of the inflow, and nitrogen species load reductions ranged from 47 to 88%. Apart from fall and winter, during which a longer hydraulic contact time seemed to be needed, the ISZs appeared to improve denitrification. Total phosphorus (TP) and OP O4 -P EMCs were significantly lower than those of the inlet. Reductions were 58% (South) and 63% (North) for TP and 78% (North) and 74% (South) for ...}, number={4}, journal={JOURNAL OF IRRIGATION AND DRAINAGE ENGINEERING}, author={Passeport, Elodie and Hunt, William F. and Line, Daniel E. and Smith, Ryan A. and Brown, Robert A.}, year={2009}, pages={505–510} }
 @inproceedings{sansalone_benty_carrasco_gulliver_hathaway_hunt_kayhanian_khambhammettu_roseen_rushton_et al._2009, title={Field Testing Guidelines for Certification of Manufactured Stormwater BMPs: Part II}, ISBN={9780784410363}, url={http://dx.doi.org/10.1061/41036(342)113}, DOI={10.1061/41036(342)113}, abstractNote={Guidance from information and field testing concepts examined by the ASCE/EWRI Subcommittee on Field Testing is presented. Field-testing of manufactured treatment devices requires critical planning and implementation through all steps of the verification process from watershed/catchment selection, to testing and analytical protocols, to data evaluation and quality assurance and control measures, to data reporting guidelines. Ultimately the goal of field testing is to provide verification of analytical or numerical models for BMPs that have been developed through scaled or full-scale controlled physical model testing. The desired goals and outcomes must be known and designed into the entire verification process. Ultimately, the entire process leads to a defensible model that represents a quantitative yardstick for both deterministic and probabilistic evaluations of a BMP for stakeholders across a range of regional conditions. This committee is focused on field verification of a BMP for separation of particulate matter (PM) from rainfall-runoff and snowmelt. Towards this goal, the entire gradation of PM requires characterization for a BMP field evaluation, in particular the suspended fraction because of the mobility and acute bio-availability of this finer fraction. On the other hand, the coarse sediment fraction is of particular importance because this coarse fraction fills many BMPs and is most labile. A fundamental, transferable and defensible methodology is considered which includes particle size distributions (PSD) combined with gravimetric index tests for PM: total suspended solids (TSS) and suspended sediment concentration (SSC). TSS by definition is the PM fraction remaining suspended in an Imhoff Cone after one hour, although current methods utilize sub-sampling generate controversy as to the meaning of the measurement. However TSS remains in use because of ubiquitous usage, regulatory significance and as an important index of treatability. In contrast, SSC provides a gravimetric analysis of the entire sample and therefore limited bias, and outstanding reliability and repeatability. Quality assurance and feedback protocol are a necessary part of the testing protocol. We must recognize the range of challenges and collect sufficient representative data within an event and across events so that the role of such uniqueness can be quantified for the specific BMP or BMPs tested.}, booktitle={World Environmental and Water Resources Congress 2009}, publisher={American Society of Civil Engineers}, author={Sansalone, John and Benty, Jeff and Carrasco, Ernie and Gulliver, John and Hathaway, Jon and Hunt, Bill and Kayhanian, Masoud and Khambhammettu, Uday and Roseen, Robert M. and Rushton, Betty and et al.}, year={2009}, month={May} }
 @inproceedings{wright_hunt_burchell, ii_perrin_mccoy_2009, title={Implementation and Performance of Stormwater Best Management Practice Retrofits in Wilmington, NC}, ISBN={9780784410363}, url={http://dx.doi.org/10.1061/41036(342)536}, DOI={10.1061/41036(342)536}, abstractNote={Burnt Mill Creek, located within downtown Wilmington, NC, is on the EPA's 303(d) list for impairment due in large part to urban stormwater runoff. The urban nature of the watershed presents challenges for restoration because of the varying land uses including single and multi-family residential areas, recreational parks, and commercial and industrial areas. Restoration efforts are multiplying in Burnt Mill Creek as a result of passionate involvement from local community leaders, and partnerships with state organizations. The Watershed Education for Communities and Local Officials (WECO) coordinated a partnership, with NCSU BAE, the City of Wilmington, as well as several other key state and local organizations and citizens groups, to obtain an EPA 319 grant that addresses stormwater management in the watershed. Community involvement has led to several retrofit BMP opportunities, including pervious pavement and rain gardens at a local YMCA, two bioretention cells installed in the parking lot at Port City Java's corporate headquarters, a stormwater wetland in a city owned communal area, and several residential scale rain gardens in an urban low income community. Twelve rain gardens and twenty four rain barrels were installed at citizen's private residences in an urban neighborhood in downtown Wilmington. Although restoration takes time, momentum continues to build in the Burnt Mill Creek watershed as resources are devoted to thoughtful education and engagement with the public.}, booktitle={World Environmental and Water Resources Congress 2009}, publisher={American Society of Civil Engineers}, author={Wright, J. D. and Hunt, W. F. and Burchell, II, M. R. and Perrin, C. A. and McCoy, E. R.}, year={2009}, month={May} }
 @article{hathaway_hunt_jadlocki_2009, title={Indicator Bacteria Removal in Storm-Water Best Management Practices in Charlotte, North Carolina}, volume={135}, ISSN={["0733-9372"]}, DOI={10.1061/(asce)ee.1943-7870.0000107}, abstractNote={Water quality degradation due to pathogen pollution is a major concern in the United States. Storm-water runoff is an important contributor to the transport of indicator bacteria from urbanized watersheds to nearby surface waters. With total maximum daily loads being established to reduce the export of indicator bacteria to surface waters, storm-water best management practices (BMPs) may be an important tool in treating indicator bacteria in runoff. However, the ability of these systems to remove indicator bacteria is not well established. A study in Charlotte, N.C., monitored nine storm-water BMPs (one wet pond, two storm-water wetlands, two dry detention basins, one bioretention area, and three proprietary devices) for fecal coliform and Escherichia coli (E. coli). A wet pond, two wetlands, a bioretention area, and a proprietary device all removed fecal coliform with an efficiency higher than 50%; however, only the wetlands and bioretention area had significantly different influent and effluent concentr...}, number={12}, journal={JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE}, author={Hathaway, J. M. and Hunt, W. F. and Jadlocki, S.}, year={2009}, month={Dec}, pages={1275–1285} }
 @article{li_sharkey_hunt_davis_2009, title={Mitigation of impervious surface hydrology using bioretention in North Carolina and Maryland}, volume={14}, DOI={10.1061/(ASCE)1084-0699(2009)14:4(407)}, abstractNote={As an increasingly adopted storm water best management practice to remedy hydrologic impairment from urban impervious- ness, bioretention facilities need rigorous field performance research and monitoring to confirm performance and improve design and maintenance recommendations. This study investigated hydrologic performance at six bioretention cells in Maryland College Park CP, a 181 m 2 cell, 50-80 cm media depth, monitored for 22 events, and Silver Spring SS, a 102 m 2 cell, 90 cm media depth, monitored for 60 events and North Carolina Greensboro G1 and G2, each approximately 317 m 2 , 120 cm media depth, both monitored for 46 events, and Louisburg L1=surface area of 162 m 2 , L2=surface area of 99 m 2 ; each had 50-60 cm fill depths, monitored for 31 and 33 events, respectively over 10-15 month periods. Outflow from each cell was recorded and inflow was either recorded or calculated from rainfall data. In Louisburg, L2 was lined with an impermeable membrane to eliminate exfiltration while L1 was unlined to allow both exfiltration and evapotranspiration. Results indicate that bioretention facilities can achieve substantial hydrologic benefits through delaying and reducing peak flows and decreasing runoff volume. A large cell media volume: drainage area ratio, and adjustments to the drainage configuration appear to improve the performance. Media layer depth may be the primary design parameter controlling hydrologic performance. Performance diminishes as rainfall depths increase and rainfall durations become longer. Annual water budget analysis suggests that approximately 20-50% of runoff entering the bioretention cells was lost to exfiltration and evapotranspiration.}, number={4}, journal={Journal of Hydrologic Engineering}, author={Li, H. and Sharkey, L. J. and Hunt, W. F. and Davis, A. P.}, year={2009}, pages={407–415} }
 @article{line_hunt_2009, title={Performance of a bioretention area and a level spreader-grass filter strip at two highway sites in North Carolina}, volume={135}, DOI={10.1061/(ASCE)0733-9437(2009)135:2(217)}, abstractNote={The pollutant removal efficiency of a bioretention area and a level spreader-grass filter strip implemented at North Carolina highway facilities was assessed. The assessment consisted of monitoring inflow, outflow, and on-site rainfall for at least 13 storm events. Monitoring included continuous discharge measurement and collecting and analyzing flow-proportional samples for each event. All samples were analyzed for solids, turbidity, and nitrogen and phosphorus forms and selected samples were analyzed for metals. The level spreader-grass filter strip had the best overall efficiency with load reduction efficiencies in all pollutants ranging from 24 to 83% and the highest reduction for total suspended solids (TSS). Much of the efficiency of this best management practice can be attributed to the 49% reduction in runoff volume from inflow to outflow. Pollutant reduction efficiencies for the bioretention area ranged from −254 to 76% with the highest reduction for TSS. The lowest or large negative efficiency w...}, number={2}, journal={Journal of Irrigation and Drainage Engineering}, author={Line, D. E. and Hunt, W. F.}, year={2009}, pages={217–224} }
 @inproceedings{jones_hunt_wright_2009, title={Rainwater Harvesting Experiences in the Humid Southeast USA}, ISBN={9780784410363}, url={http://dx.doi.org/10.1061/41036(342)209}, DOI={10.1061/41036(342)209}, abstractNote={Due to recent concerns over the environmental impact of stormwater runoff and increased water demands, interest in rainwater harvesting systems as an innovative stormwater treatment practice has developed in humid, well developed regions, such as the southeastern United States. Rainwater harvesting systems are designed to capture runoff from rooftops. The captured water can be used as an alternative to municipal or well water for non-potable applications. The water can be used for irrigation, vehicle washing, toilet flushing, and other non-potable uses. Harvested water can potentially be used for potable uses with proper treatment. Water harvesting systems can reduce peak flows and pollutant loads as well as conserve valuable resources. In order to better understand the anticipated usage and reliability of rainwater harvesting systems in the southeastern United States, a monitoring study was conducted at 5 rainwater harvesting systems in North Carolina, measuring cistern water levels and rainfall. Harvested water was used for a variety of applications including vehicle washing, irrigation, and toilet flushing. In order for water harvesting to be a viable solution for stormwater management the harvested water must be used between storm events. The system must be drained as much as possible to provide storage and peak flow mitigation for the next storm event. Results of the monitoring study showed that the rainwater harvesting systems were typically underutilized. Water usage was most consistent at the location where harvested rainwater was used to flush a toilet; however, the water level within the cistern only dropped below 80% of capacity on one occasion during the 30 month monitoring period. Research showed that the harvested water may require a dedicated use for water harvesting to be an effective stormwater management tool.}, booktitle={World Environmental and Water Resources Congress 2009}, publisher={American Society of Civil Engineers}, author={Jones, Matthew and Hunt, William F. and Wright, Jason}, year={2009}, month={May} }
 @inproceedings{wright_hunt_2009, title={Research of Hydrologic and Water Quality Performance of 4 Linear Wetlands in Eastern North Carolina}, ISBN={9780784410363}, url={http://dx.doi.org/10.1061/41036(342)148}, DOI={10.1061/41036(342)148}, abstractNote={The North Carolina Department of Transportation is charged by an agreement with the North Carolina Department of Environment and Natural Resources to treat stormwater from NC DOT facilities across North Carolina. One heretofore unaccounted treatment is hundreds of miles of right-of-way swales in eastern North Carolina. It is possible that these serendipitous practices are improving runoff quality along theses highways. If so, an assessment of their performance is needed. Four existing right-of-way linear swales along I–40 east of I–95 will be monitored to determine their hydrologic and water quality effectiveness. Two different treatments are being examined: one swale that is unaltered and one that has been allowed to establish wetland conditions. There are two examples of each. Monitoring will also address the impact of the vegetated filter strip between the shoulder and the edge of the swale. Monitoring began in August of 2008. Samples are being collected from 18 events and analyzed for TN, TKN, NH4—N, NO2–3—N, TP, and TSS.}, booktitle={World Environmental and Water Resources Congress 2009}, publisher={American Society of Civil Engineers}, author={Wright, J. D. and Hunt, W. F.}, year={2009}, month={May} }
 @inproceedings{mcnett_hunt_2009, title={Water Quality Assessed by Benthic Macro-Invertebrates: Proposing the WQABI Method}, ISBN={9780784410363}, url={http://dx.doi.org/10.1061/41036(342)542}, DOI={10.1061/41036(342)542}, abstractNote={Stormwater experts agree that the currently used percent removal methodology metric has many flaws, and some have suggested utilizing a BMP effluent concentration metric. This paper examines a new method that establishes effluent target concentrations for BMPs based on the health of macro-invertebrates in the receiving water. 193 ambient water quality monitoring stations in North Carolina were paired with benthic macro-invertebrate health ratings collected in very close proximity. Water quality for the sites ranged from Excellent to Poor and was divided into three distinct eco-regions. Median NO 3 + NO 2 , TKN, TN, and TP concentrations all increased with poorer benthic ratings; however, there was no such trend with respect to DO, TSS, and Fecal Coliforms. Overall, the new method was most effective in the Piedmont and Coastal eco-regions; however with more data collection, the Mountain eco-region may also benefit. For example, if regulators were to require Good water quality in the Piedmont eco-region, designers would have to limit effluent concentrations of TN and TP would be 0.99 mg/L and 0.11 mg/L, respectively, per the method presented herein.}, booktitle={World Environmental and Water Resources Congress 2009}, publisher={American Society of Civil Engineers}, author={McNett, J. K. and Hunt, W. F.}, year={2009}, month={May} }
 @article{hathaway_hunt_jennings_2008, title={Afield study of green roof hydrologic and water quality performance}, volume={51}, number={1}, journal={Transactions of the ASABE}, author={Hathaway, A. M. and Hunt, W. F. and Jennings, G. D.}, year={2008}, pages={37–44} }
 @inproceedings{brown_hunt_2008, title={Bioretention Performance in the Upper Coastal Plain of North Carolina}, ISBN={9780784410097}, url={http://dx.doi.org/10.1061/41009(333)95}, DOI={10.1061/41009(333)95}, abstractNote={Bioretention is a principal low impact development (LID) practice. A study underway in North Carolina is examining the performance of bioretention cells with respect to hydrology and water quality under varying vegetative covers and media depths in the sandy in-situ soils of the upper coastal plain. Two types of cells are being monitored in both Rocky Mount and Nashville. In Rocky Mount, the cells were designed with 0.9 m deep media depth and a 0.6 m deep internal water storage layer (IWS). The IWS is intended to create anaerobic conditions to increase the rate of nitrate and total nitrogen reduction. Current data shows the IWS having a strong effect on flow reduction. Out of 37 events that were monitored since September 2007, outflow was generated in the grassed cell and mulch/shrub cell two and one time, respectively. Grab samples have been collected from the underdrains after an event to quantify treatment. Preliminary data from ten events show concentration reductions of total nitrogen, total phosphorus, and total suspended solids of 80, 72, and 92%, respectively. In Nashville, two sets of cells were designed without IWS and with media depths of 0.6 and 0.9 m. Preliminary data shows the deeper media depths meet a LID hydrology goal of volume reduction more frequently. Data collected from these four sets of cells will be used to compare performance of bioretention in the sandy in-situ soils of the upper coastal plain to those sited in clayey soils from past studies in the Piedmont region.}, booktitle={Low Impact Development for Urban Ecosystem and Habitat Protection}, publisher={American Society of Civil Engineers}, author={Brown, R. A. and Hunt, W. F.}, year={2008}, month={Nov} }
 @inproceedings{roseen_carrasco_cheng_hunt_johnston_mailloux_stein_williams_2008, title={Data Reporting Guidelines for Certification of Manufactured Stormwater BMPs}, ISBN={9780784409763}, url={http://dx.doi.org/10.1061/40976(316)16}, DOI={10.1061/40976(316)16}, abstractNote={With the increasing need for the independent field testing of proprietary devices comes the importance of consistent data reporting guidelines to be used when reporting to regulatory agencies. The need for standardized reporting is underscored by the tremendous impact the range of factors can have upon testing results. These factors include the testing environment, experimental design, testing methodologies, statistical analysis, and data presentation. The need for the consistency is underscored by the complex influence these factors have upon performance results. A clear and consistent data reporting approach can ensure that these biases are minimized, well understood, and that representative field testing can be effectively evaluated by the regulatory agency. Data Reporting guidelines presented here were developed as part of the ASCE/EWRI Committee on Guidelines for Certification of Manufactured Stormwater BMPs.}, booktitle={World Environmental and Water Resources Congress 2008}, publisher={American Society of Civil Engineers}, author={Roseen, Robert M. and Carrasco, Ernie and Cheng, Yuan and Hunt, Bill and Johnston, Charlene and Mailloux, Jim and Stein, Walt and Williams, Tim}, year={2008}, month={May} }
 @inproceedings{jones_hunt_2008, title={Effect of Bioretention on Runoff Temperature in Trout Sensitive Regions}, ISBN={9780784410097}, url={http://dx.doi.org/10.1061/41009(333)80}, DOI={10.1061/41009(333)80}, abstractNote={Although it has been established that thermal pollution from urban stormwater can negatively impact the aquatic ecosystem, there are few mechanisms available to reduce the temperature or urban stormwater runoff. A monitoring study was conducted at 4 bioretention areas in western North Carolina, located along the southeastern extent of United States trout populations, to examine the effect these systems have on runoff temperature and identify any design criteria pertinent to temperature reduction. Median runoff temperatures leaving the pavement surfaces, based on storm events, exceeded the 21°C upper avoidance temperature of trout at all sites during the months of June through September. Of the bioretention areas studied, the two systems that covered an area smaller than 10% of their contributing watershed were able to significantly (p<0.01) reduce both maximum and median storm temperatures between the inlet and outlet. At the two bioretention areas that were larger than 10% of their contributing watershed area, maximum effluent temperatures were significantly (p<0.01) cooler than influent temperatures; however, there was no significant (p<0.05) difference between median influent and effluent temperatures. Despite reductions in temperature, effluent temperatures were not significantly (p<0.05) cooler than the upper avoidance temperature for trout at any of the monitoring locations. There was evidence that substantial reductions in runoff volume occurred at all bioretention areas, especially the systems that were larger than 10% of their contributing watershed. Overall, monitoring results indicated that bioretention areas served as effective treatment mechanisms for reducing, but not eliminating, the thermal impacts associated with urban stormwater runoff.}, booktitle={Low Impact Development for Urban Ecosystem and Habitat Protection}, publisher={American Society of Civil Engineers}, author={Jones, Matthew and Hunt, William F.}, year={2008}, month={Nov} }
 @inproceedings{jarrett_hunt_berghage_2008, title={Evaluating a Spreadsheet Model to Predict Green Roof Stormwater Management}, ISBN={9780784410073}, url={http://dx.doi.org/10.1061/41007(331)23}, DOI={10.1061/41007(331)23}, abstractNote={The departments of Agricultural and Biological Engineering and Horticulture at the Pennsylvania State University have combined efforts to quantify the stormwater attenuation capabilities of extensive green-roof systems. This green-roof system consisted of a roof with a conventional flat-roof covering, a 0.5-in thick Enkadrainage layer, 3.5 in of porous medium, and Sedum spurium planted 3.0 in on center. The combined layers of this green roof had a maximum retention of 1.5 in and a saturated hydraulic conductivity of 0.43 in/s. The green roof system was modeled using a checkbook approach with daily rainfall depth as an input and ET and runoff as the outputs. The AGRR model was applied to 28 years (1976-2003) of rainfall data in Raleigh, NC, and showed that 45% of the annual rainfall volume (depth) can be retained on the green roof. Increasing the volume of storage does not improve the roofs ability to retain rain water. Providing only 0.125 in of roof storage will still cause over 30% of the annual rain depth to be retained on the roof.}, booktitle={Low Impact Development}, publisher={American Society of Civil Engineers}, author={Jarrett, A. R. and Hunt, W. F. and Berghage, R. D.}, year={2008}, month={Nov} }
 @article{line_jennings_shaffer_calabria_hunt_2008, title={Evaluating the effectiveness of two stormwater wetlands in North Carolina}, volume={51}, number={2}, journal={Transactions of the ASABE}, author={Line, D. E. and Jennings, G. D. and Shaffer, M. B. and Calabria, J. and Hunt, W. F.}, year={2008}, pages={521–528} }
 @inproceedings{collins_hunt_hathaway_2008, title={Evaluation of Various Types of Permeable Pavement with Respect to Water Quality Improvement and Flood Control}, ISBN={9780784410073}, url={http://dx.doi.org/10.1061/41007(331)25}, DOI={10.1061/41007(331)25}, abstractNote={In North Carolina and several other U.S. states, all permeable pavements are currently considered to have similar capabilities in reducing runoff, but are not credited with improving water quality. Previous research conducted by the North Carolina State University on one particular permeable pavement type has shown that when compared to runoff from an adjoining asphalt lot, permeable pavement exfiltrate contained significantly lower concentrations of phosphorous and zinc, as well as reductions in total nitrogen. To further test various permeable pavement designs, a parking lot consisting of four different types of permeable pavements and standard asphalt was constructed in Kinston, NC. The permeable pavement sections consist of porous concrete (PC), permeable interlocking concrete pavers (PICP) with 8.5 % void space, PICP with 12.9 % void space, and concrete grid pavers (CGP), each covering a 1200 sq. ft. area with a 10 in. gravel storage layer. The purpose of this study is to evaluate and compare the effects of each pavement type on water quality and runoff reduction. Conclusions on the difference in reduction between each pavement type have not previously been determined. Site analyses on every rainfall event began in March, 2006, and will continue for one year. Preliminary results indicate significant peak flow and volume reductions in all permeable pavement exfiltrates. Additionally, there has been little to no runoff observed from any of the pervious sections. As a result of the Kinston study, it is expected that the state of North Carolina will be able to make an informed judgment on how much pollutant removal credit permeable pavements should receive when implemented as stormwater best management practices. Also, this study can be used to determine whether or not stormwater credit should vary based on pavement type.}, booktitle={Low Impact Development}, publisher={American Society of Civil Engineers}, author={Collins, Kelly A. and Hunt, William F. and Hathaway, Jon M.}, year={2008}, month={Nov} }
 @inproceedings{winston_hunt_2008, title={Field Evaluation of Level Spreaders for Runoff Reduction and Water Quality Impacts}, ISBN={9780784410097}, url={http://dx.doi.org/10.1061/41009(333)100}, DOI={10.1061/41009(333)100}, abstractNote={Traditional construction practices lead to degradation of watershed hydrology through increased flow in pipe networks, increased flow volumes, decreased groundwater recharge, and increased peak flows. Recent regulations in North Carolina have led to the use of level spreaders in combination with a vegetated buffer as an end-of-pipe method to reduce erosion and decrease stresses on riparian buffers. However, little research has been done to evaluate their effectiveness. A total of four level spreaders were studied at two sites, Apex and Louisburg, NC. At each site, stormwater from small, impervious watersheds (0.4 ha or less) was conveyed proportionally to two level spreaders. Flow was released along the length of the level spreaders and into two vegetated buffers. This study evaluated the hydrologic and water quality impacts of level spreaders (combined with vegetated buffers) as an LID practice. The idea is to disperse flow across the length of the buffer, in order to improve infiltration capacity of the buffer. Varying buffer widths and buffer vegetation were studied. Preliminary findings show that substantial reduction in peak flow rate and flow volume can be expected when this LID practice is implemented. This system was also studied for its impacts on nitrogen, phosphorous, suspended solids, and runoff temperature. Further data collection and analysis should provide design engineers guidance on the functionality of this system.}, booktitle={Low Impact Development for Urban Ecosystem and Habitat Protection}, publisher={American Society of Civil Engineers}, author={Winston, Ryan J. and Hunt, William F.}, year={2008}, month={Nov} }
 @inproceedings{hathaway_hunt_2008, title={Field Evaluation of Level Spreaders in the Piedmont of North Carolina}, ISBN={9780784410073}, url={http://dx.doi.org/10.1061/41007(331)18}, DOI={10.1061/41007(331)18}, abstractNote={Level Spreaders are commonly used in combination with riparian buffers as a storm water Best Management Practice (BMP) in many parts of the United States. These systems have not been extensively studied in urban environments to determine if they can provide a long term water quality benefit. In Winter, 2005, 24 level spreaders were evaluated in the Piedmont of North Carolina. Detailed observations were made at 20 of these locations. The results of the study indicate that level spreaders may not be the versatile structure they are perceived to be. No level spreader — riparian buffer system was able to provide diffuse flow through the riparian buffer from the level spreader to the stream. Common causes for failure to maintain diffuse flow included: lack of maintenance (12 cases), poor design (11), riparian topography / content (11), level spreader lip not level (7), built with easily eroded materials (6), poor construction methods (3), and human interference (2). This field evaluation indicates that level spreader systems may need design revisions, construction guidance, and maintenance requirements before they continue to be used en masse.}, booktitle={Low Impact Development}, publisher={American Society of Civil Engineers}, author={Hathaway, J. M. and Hunt, W. F.}, year={2008}, month={Nov} }
 @article{hathaway_hunt_2008, title={Field evaluation of level spreaders in the Piedmont of North Carolina}, volume={134}, DOI={10.1061/(ASCE)0733-9437(2008)134:4(538)}, abstractNote={Level spreaders are commonly used in combination with riparian buffers as a stormwater best management practice in many parts of the United States. These systems have not been extensively studied in urbanized environments to determine if they can provide a long-term water quality benefit. In winter 2005, 24 level spreaders were evaluated in the Piedmont of North Carolina. Detailed observations were made at 20 of these locations. The results of the study indicate that level spreaders may not be the versatile structure they are perceived to be. No level spreader-riparian buffer system was able to provide diffuse flow through the riparian buffer from the level spreader to the stream. Common causes for failure to maintain diffuse flow included: lack of maintenance (12 cases), poor design (11), riparian topography/content (11), level spreader lip not level (seven), built with easily eroded materials (six), poor construction methods (three), and human interference (two). This field evaluation indicates that lev...}, number={4}, journal={Journal of Irrigation and Drainage Engineering}, author={Hathaway, J. M. and Hunt, W. F.}, year={2008}, pages={538–542} }
 @inproceedings{collins_hunt_hathaway_2008, title={Hydrologic and Water Quality Evaluation of Four Permeable Pavements in North Carolina, USA}, ISBN={9780784410097}, url={http://dx.doi.org/10.1061/41009(333)27}, DOI={10.1061/41009(333)27}, abstractNote={A permeable pavement parking lot in eastern North Carolina consisting of four types of permeable pavement and standard asphalt was monitored from June 2006 to J uly 2007 for hydrologic differences in pavement surface runoff volumes, total outflow volumes, peak flow rates, and time to peak, and from January 2007 to July 2007 for water quality concentrations. The four permeable sections were pervious concrete (PC), two types of permeable interlocking concrete pavement (PICP) with small-sized aggregate in the joints and having 12.9% (PICP1) and 8.5% (PICP2) open surface area, and concrete grid pavers (CGP) filled with sand. All permeable pavements significantly and substantially reduced surface runoff volumes and peak flow rates from those of asphalt (p<0.01). Of the permeable pavements, CGP generated the greatest surface runoff volumes (p<0.01). The PICP1 and CGP cells generated significantly lower outflow volumes than all other sections evaluated (p<0.01), and had the lowest peak flows and the longest time to peak. The response of the PICP1 cell was likely due to a n increased base storage volume resulting from an elevated pipe underdrain; whereas, the CGP cell response was attributed to water retention in the sand fill layer. Overall, different permeable pavement sections performed similarly, but were substantially different from asphalt. The pH of permeable pavement subsurface drainage was higher than that of asphalt runoff (p<0.01) with the PC cell having the highest pH values (p<0.01). Permeable pavement subsurface drainage had lower NH4-N (p<0.01) and TKN concentrations than asphalt runoff and atmospheric deposition. With the exception of the CGP cell, permeable pavements had higher NO2,3-N concentrations than asphalt (p<0.01), a probable result of nitrification occurring within the permeable pavement profile. Overall, different permeable pavement sections performed similarly to one another with respect to water quality, but the CGP cell appeared to improve stormwater runoff nitrogen concentrations.}, booktitle={Low Impact Development for Urban Ecosystem and Habitat Protection}, publisher={American Society of Civil Engineers}, author={Collins, Kelly A. and Hunt, William F. and Hathaway, Jon M.}, year={2008}, month={Nov} }
 @article{collins_hunt_hathaway_2008, title={Hydrologic comparison of four types of permeable pavement and standard asphalt in eastern North Carolina}, volume={13}, DOI={10.1061/(ASCE)1084-0699(2008)13:12(1146)}, abstractNote={A permeable pavement parking lot in eastern North Carolina consisting of four types of permeable pavement and standard asphalt was monitored from June 2006 to July 2007 for hydrologic differences in pavement surface runoff volumes, total outflow volumes, peak flow rates, and time to peak. The four permeable sections were pervious concrete (PC), two types of permeable interlocking concrete pavement (PICP) with small-sized aggregate in the joints and having 12.9% (PICP1) and 8.5% (PICP2) open surface area, and concrete grid pavers (CGP) filled with sand. The site was located in poorly drained soils, and all permeable sections were underlain by a crushed stone base layer with a perforated underdrain. All permeable pavements significantly reduced surface runoff volumes and peak flow rates from those of asphalt (p<0.01) . Of the permeable pavements, CGP generated the greatest surface runoff volumes (p<0.01) . The PICP1 and CGP cells generated significantly lower total outflow volumes than all other sections ev...}, number={12}, journal={Journal of Hydrologic Engineering}, author={Collins, K. A. and Hunt, W. F. and Hathaway, J. M.}, year={2008}, pages={1146–1157} }
 @inproceedings{wright_hunt_burchell, ii_perrin_2008, title={Implementation and Performance of Stormwater Best Management Practice Retrofits in Wilmington, NC}, ISBN={9780784409763}, url={http://dx.doi.org/10.1061/40976(316)647}, DOI={10.1061/40976(316)647}, abstractNote={Text: Burnt Mill Creek, located within downtown Wilmington, NC, is on the EPA’s 303(d) list for impairment due in large part to urban stormwater runoff. The urban nature of the watershed presents challenges for restoration because of the varying land uses. Restoration efforts are multiplying in Burnt Mill Creek as a result of passionate involvement from local community leaders, and partnerships with state organizations. The Watershed Education for Communities and Local Officials (WECO) coordinated a partnership, with NCSU BAE, the City of Wilmington, as well as several other key state and local organizations and citizens groups, to obtain an EPA 319 grant that addresses stormwater management in the watershed. Community involvement has led to several retrofit BMP opportunities, including pervious pavement and rain gardens at a local YMCA, a stormwater wetland at a townhome community, two bioretention cells installed in the parking lot at Port City Java’s corporate headquarters, and a stormwater wetland in a city owned communal area. A crusher run gravel parking lot at the YMCA was a substantial source of sediment into Burnt Mill Creek. The gravel was replaced with porous concrete, two rain gardens, and grassed landscaping. A stormwater wetland was installed in a townhome community to treat a 5 acre drainage area. Runoff from the parking lot at the Port City Java headquarters was intercepted by a sod bioretention area. A stormwater wetland was constructed to treat a 5.5 acre watershed that drains through City owned open space adjacent to Burnt Mill Creek. Monitoring conducted at each site and in the watershed will help determine the effects of the bmp’s individually and on the watershed as a whole. Although restoration takes time, momentum continues to build in the Burnt Mill Creek watershed as resources are devoted to thoughtful education and engagement with the public.}, booktitle={World Environmental and Water Resources Congress 2008}, publisher={American Society of Civil Engineers}, author={Wright, J. D. and Hunt, W. F. and Burchell, II, M. R. and Perrin, C. A.}, year={2008}, month={May} }
 @inproceedings{wright_perrin_hunt_mccoy_2008, title={Implementation of Low Impact Development Retrofits in a Low Income Neighborhood in Wilmington, NC}, ISBN={9780784410097}, url={http://dx.doi.org/10.1061/41009(333)115}, DOI={10.1061/41009(333)115}, abstractNote={Burnt Mill Creek, located within downtown Wilmington, NC, is on the EPAâ€TMs 303(d) list for impairment due in large part to urban stormwater runoff. The urban nature of the watershed presents challenges for restoration because of the varying land uses including single and multifamily residential areas, recreational parks, and commercial and industrial areas. Watershed Education for Communities and Local Officials (WECO) of NC State University (NCSU) coordinated a partnership, with NCSU Dept. of Biological and Agricultural Engineering (BAE), as well as several other key state and local organizations and citizens groups, to obtain an EPA 319 grant that addresses stormwater management in the watershed. Collaboration with community leaders has led to several retrofit opportunities and successful partnerships. Often in large scale watershed retrofit projects, education and retrofit opportunities in low income areas are overlooked. This paper focuses specifically on the partnership with one citizens group, the Bottom Neighborhood Empowerment Association (BNEA). The bottom area, called the bottom because it is one of the lowest points in the watershed, is a dense urban neighborhood where many residents have incomes lower than the median income of Wilmington and New Hanover County (Wilmington median income is $42,000, New Hanover County $41,000; areas in BMC between $22,000 and $34,000 depending on census tract) (NC Census, 2000). BNEA is a group of citizens living in the bottom area who are working to improve the quality of life in their neighborhood. Cooperation with BNEA has led to several educational and LID retrofit opportunities including three educational workshops held in the community, installation of ten rain gardens in community areas and private residences, and distribution of twenty-four 65 gallon rain barrels. A survey developed and distributed by an NCSU graduate student showed that each resident who responded found some stormwater educational benefit to participating in the workshops and the retrofit efforts.}, booktitle={Low Impact Development for Urban Ecosystem and Habitat Protection}, publisher={American Society of Civil Engineers}, author={Wright, J. D. and Perrin, C. A. and Hunt, W. F. and McCoy, E. R.}, year={2008}, month={Nov} }
 @inproceedings{hunt_england_debruijn_gee_guo_lord_miller_mosheni_perry_2008, title={Inspection and Maintenance Guidance for Manufactured BMPs}, ISBN={9780784409763}, url={http://dx.doi.org/10.1061/40976(316)19}, DOI={10.1061/40976(316)19}, abstractNote={ASCE/EWRI has assembled a Task Committee on guidelines for certification of manufactured stormwater BMPs. A nine-member subcommittee for maintenance was tasked by the larger committee to develop maintenance guidelines for manufactured stormwater BMPs. The subcommittee has developed recommendations for manufactured BMP maintenance in the following seven areas: (1) designing for maintenance, (2) defining standard maintenance triggers, (3) defining maintenance fundamentals for all manufactured BMPs, (4) defining maintenance tasks by BMP design; hydrodynamic or filter design, (5) identifying entities best able to maintain manufactured BMPs, and training requirements, (6) identifying entities to train maintenance providers, and (7) reviewing recommended disposal techniques for captured pollutants.}, booktitle={World Environmental and Water Resources Congress 2008}, publisher={American Society of Civil Engineers}, author={Hunt, William F. and England, Gordon and DeBruijn, Hans and Gee, Richard and Guo, Qizhong (George) and Lord, William and Miller, Mark and Mosheni, Omid and Perry, Scott}, year={2008}, month={May} }
 @inproceedings{wright_hunt_2008, title={LID Feasibility, Design, and Implementation at Cape Lookout National Seashore}, ISBN={9780784410097}, url={http://dx.doi.org/10.1061/41009(333)105}, DOI={10.1061/41009(333)105}, abstractNote={The grounds surrounding the Core Sound Waterfowl Museum and the Cape Lookout National Seashore Visitor Center provide little stormwater runoff treatment as they are currently configured. Because both facilities are immediately adjacent to Core Sound and Back Sound, any pollutants that fall on the grounds, particularly on impermeable surfaces, can easily migrate to sensitive waters. Also, as thousands of visitors pass through the National Park Service property each year, there is a tremendous opportunity to demonstrate low impact development practices to reduce the amount of runoff, and its associated pollutants, entering the sounds. Faculty and students from the Department of Biological and Agricultural Engineering Department at NC State University evaluated the site for potential best management practices. They identified 13 potential retrofits for the Core Sound Waterfowl Museum and the Cape Lookout Visitor Center including water harvesting, rain gardens, and permeable pavement. Design elements including a cost estimate for each potential BMP has been developed for future use by the visitor center and the museum. Detailed designs were completed for five of the identified BMP's including two rain gardens, a water harvesting system, and permeable pavement. Three of the BMP's were installed: one at the Cape Fear Visitor Center and two at the Core Sound Waterfowl Museum. An 7.5 m 2 (80 ft 2 ) rain garden was constructed that treats the runoff from a rooftop at the museum. A 5,678 L (1,500 gal) cistern was installed that captures runoff from 70 m 2 (750 ft 2 ) of rooftop at the museum. The harvested water will be used to irrigate the landscaping at the museum. Runoff from the rooftop at the Cape Lookout Visitor Center will be treated in a rain garden located near the entrance. Each of the practices will improve the quality of the stormwater leaving the site while serving to educate the public about using low impact development to treat stormwater runoff.}, booktitle={Low Impact Development for Urban Ecosystem and Habitat Protection}, publisher={American Society of Civil Engineers}, author={Wright, J. D. and Hunt, W. F.}, year={2008}, month={Nov} }
 @inproceedings{woodward_hunt_hartup_2008, title={Lessons Learned: The North Carolina Backyard Rain Garden Program}, ISBN={9780784410097}, url={http://dx.doi.org/10.1061/41009(333)104}, DOI={10.1061/41009(333)104}, abstractNote={Research conducted at the North Carolina State University and elsewhere has determined that bioretention practices are very effective in reducing polluted stormwater runoff from urban areas. Smaller residential bioretention areas, also known as rain gardens, have proven to be an effective means of removing metals, nutrients, sediment and fecal coliform provided that they have been designed, sited, constructed and maintained properly. The university, local and state governments have been promoting the installation of rain gardens and other stormwater practices in Phase I and II communities for many years; however, very few homeowners and commercial landscape contractors have a working knowledge of the benefits of rain gardens, their installation or their maintenance requirements. To help promote rain gardens and address these needs, the North Carolina Backyard Rain Garden Program was implemented during the summer of 2006 in a six-county pilot area. Funded as an EPA 319(h) project, the program (1) developed an education program by conducting homeowner workshops in each county, (2) installed more than 40 residential demonstration rain gardens, and (3) developed educational and reference materials making them available at the following website: www.bae.ncsu.edu/topic/rain_garden. More recently, an assessment was performed to determine: 1) How many rain gardens continued to function properly, 2) What, if any maintenance had been performed, 3) Common traits among the cooperators with successful rain gardens. 4) Education needs for homeowners and installers.}, booktitle={Low Impact Development for Urban Ecosystem and Habitat Protection}, publisher={American Society of Civil Engineers}, author={Woodward, Mitch and Hunt, William F. and Hartup, Wendi}, year={2008}, month={Nov} }
 @inproceedings{english_hunt_2008, title={Low Impact Development and Permeable Interlocking Concrete Pavements: Working with Industry for Material Development and Training Offerings}, ISBN={9780784410097}, url={http://dx.doi.org/10.1061/41009(333)22}, DOI={10.1061/41009(333)22}, abstractNote={Green infrastructure supports the concept of using natural ecosystems to support a healthy urban environment, specifically to preserve and enhance water, air, cultural and visual resources. Low impact development (LID) is implemented through a set of tools which support the development and enhancement of green infrastructure. Permeable interlocking concrete pavement (PICP) is an LID tool which enables a broad range of opportunities to support integrated green infrastructure goals in new and redeveloped urban environments while meeting regulatory directives and other drivers for implementation. PICP has a variety of design options for stormwater mitigation, increased infiltration, and pollutant control. It is essential for users, and potential users, of this product to fully understand PICP benefits and constraints.}, booktitle={Low Impact Development for Urban Ecosystem and Habitat Protection}, publisher={American Society of Civil Engineers}, author={English, Ann and Hunt, William F.}, year={2008}, month={Nov} }
 @inproceedings{hathaway_hunt_wright_jadlocki_2008, title={Pathogen Removal Performance of Best Management Practices in Charlotte and Wilmington, North Carolina}, ISBN={9780784409763}, url={http://dx.doi.org/10.1061/40976(316)648}, DOI={10.1061/40976(316)648}, abstractNote={Pathogens are a target pollutant in many parts of North Carolina, particularly in areas that drain to shellfish waters. Single storm limits have been established for pathogen indicators in fresh water (200 cfu/ 100 ml for fecal coliform, 126 col/100 ml for E. coli, and 33 cfu/100 ml for enterrococcus) and marine waters (35 cfu/100 ml for enterrococcus) being used as full body recreational areas in an attempt to reduce public health risks. Runoff samples collected in coastal counties have often exceeded fecal counts of 20,000 cfu/ 100 ml (Bright 2007). The NCSU Biological and Agricultural Engineering Department monitored 14 total stormwater BMPs, 9 in Charlotte, NC, and 5 in Wilmington, NC, to evaluate their efficiency with respect to indicator bacteria removal. The study locations included 2 bioretention areas, 4 stormwater wetlands, 3 wet ponds, 2 dry detention, and 3 proprietary BMPs.}, booktitle={World Environmental and Water Resources Congress 2008}, publisher={American Society of Civil Engineers}, author={Hathaway, J. M. and Hunt, W. F. and Wright, J. D. and Jadlocki, S. J.}, year={2008}, month={May} }
 @inproceedings{jones_hunt_2008, title={Performance of Rainwater Harvesting Systems in the Southeastern United States}, ISBN={9780784410097}, url={http://dx.doi.org/10.1061/41009(333)30}, DOI={10.1061/41009(333)30}, abstractNote={Due to recent concerns over the environmental impact of stormwater runoff and increased water demands, interest in rainwater harvesting systems has developed in humid, well developed regions, such as the southeastern United States. In order to better understand the anticipated usage and reliability of rainwater harvesting systems in the southeastern United States, a monitoring study was conducted at 3 rainwater harvesting systems in North Carolina, measuring cistern water levels and rainfall. Results of the monitoring study showed that the rainwater harvesting systems were typically underutilized. Water usage was most consistent at the location where harvested rainwater was used to flush a toilet; however, the water level within the cistern only dropped below 80% of capacity on one occasion during the 30 month monitoring period. A computer model was developed to simulate the performance of rainwater harvesting systems based upon historical rainfall data and anticipated usage by evaluating a daily or hourly water balance. The rainwater harvesting computer model was used to simulate the performance of a 55-gallon (208 liter) rain barrel commonly used by homeowners in this region to meet household gardening demands. A variety of turfgrass irrigation scenarios were examined, varying the size of the irrigated area and contributing rooftop. Simulation results showed that the rain barrel was not able to adequately meet irrigation demands. The low volume of water the rain barrel was able to supply for irrigation and the large amount of overflow indicated that the rain barrel was not able to effectively utilize the potential water supply coming from the rooftop and provided minimal runoff volume reduction.}, booktitle={Low Impact Development for Urban Ecosystem and Habitat Protection}, publisher={American Society of Civil Engineers}, author={Jones, Matthew and Hunt, William F.}, year={2008}, month={Nov} }
 @article{hunt_smith_jadlocki_hathaway_eubanks_2008, title={Pollutant removal and peak flow mitigation by a bioretention cell in urban Charlotte, NC}, volume={134}, DOI={10.1061/(asce)0733-9372(2008)134:5(403)}, abstractNote={Bioretention is a stormwater treatment practice that has gained popularity due to its aesthetics, potential to reduce flooding, and early documented improvements to stormwater quality. A bioretention cell in an urban setting was examined in Charlotte, N.C. from 2004 to 2006. Flow-weighted, composite water quality samples were collected for 23 events and analyzed for TKN, N H4 -N , N O2-3 -N , TP, TSS, BOD-5, Cu, Zn, Fe, and Pb. Grab samples were collected from 19 storms for fecal coliform and 14 events for Escherichia coli (E. coli). There were significant reductions (p<0.05) in the concentrations of TN, TKN, N H4 -N , BOD-5, fecal coliform, E. Coli, TSS, Cu, Zn, and Pb. Iron concentrations significantly increased (p<0.05) . N O2-3 -N concentrations were essentially unchanged. Efficiency ratios for TN, TKN, N H4 -N , TP, and TSS were 0.32, 0.44, 0.73, 0.31, and 0.60, respectively. Fecal coliform and E. coli efficiency ratios were 0.69 and 0.71, respectively. Efficiency ratios for Zn, Cu, and Pb were 0.77,...}, number={5}, journal={Journal of Environmental Engineering (New York, N.Y.)}, author={Hunt, W. F. and Smith, J. T. and Jadlocki, S. J. and Hathaway, J. M. and Eubanks, P. R.}, year={2008}, pages={403–408} }
 @inproceedings{burchell_hunt, iii_chescheir_2008, title={Reducing Stormwater Bacteria Loads to North Carolina Ocean Recreational Areas Using a Dune Infiltration System}, ISBN={9780784409763}, url={http://dx.doi.org/10.1061/40976(316)34}, DOI={10.1061/40976(316)34}, abstractNote={Coastal towns traditionally discharge stormwater containing bacteria and pathogens to the ocean via ocean outfalls, increasing the potential for serious diseases to recreational swimmers. To combat this risk, an innovative coastal BMP, a Dune Infiltration System (DIS), was designed and installed at two locations in Kure Beach, N.C. to divert stormwater from outfalls into the dunes. Post-construction monitoring of these systems during 25 storm events in 2006 showed that this design was economically and technically feasible, because 97% of the stormwater was diverted into the dunes, the dunes remained structurally stable, and Enterococcus concentrations entering from the outfalls were reduced by over 97%. However bacterial transport surrounding the system remained poorly understood, which limited the certainty at which this system could be recommended for further implementation. Therefore, a series of additional water table and water quality wells were installed at each of the systems, and in a nearby control dune, during the summer of 2007. After six-months, bacterial concentrations in the groundwater at the dune-beach interface near the dune infiltration sites are similar to that of the control area. Introduction As populations increase near our beaches, new development and increased imperviousness generates more stormwater. Coastal towns traditionally discharge stormwater containing, among other pollutants, bacteria and pathogens to the ocean via ocean outfalls. More development equates to more stormwater flowing into the oceans under current management techniques, increasing the potential for serious diseases to recreational swimmers. The Town of Kure Beach, NC has a number of stormwater outfalls that discharge on to the beach, sometimes directly flowing into the ocean with little infiltration into the sand. Stormwater samples collected from two outfalls draining from the town had Enterococcus levels that ranged from 1.3 cm/hr). The dunes in Kure Beach have a relatively high elevation (~ 5.0 m (16.5 ft) above MSL), while the groundwater elevation, though subject to tidal influences, is relatively low (0.31.0 m (1-3 ft)). Coupled with high infiltration rates common with beach sand, this makes for an ideal location for infiltration. Two of these systems were installed in February 2006 to capture stormwater runoff from the L Ave. outfall (1.9 ha. (4.7 acre) watershed) and M Ave. outfall (3.2 ha (8.5 acre) watershed). Both watersheds had similar mixed urban/residential development. The designed DIS for L Ave. required 12 chambers and was approximately 30 m (100 ft) long, while the M Ave. system required 22 chambers and was approximately 60 m (200 ft) long. Stormwater was diverted into each system form the outfalls in a subsurface concrete vault. These systems were installed 50 m (160 ft) from the mean high tide line. Figure 1 shows the system at L Ave. (known as Site L) during installation, and the condition of the dunes 15 months following installation and replanting of the dune vegetation. Additional details of the design procedure and installation of the DIS can be found in Bright (2006) and Burchell et al. (2007). Following storm event data collection in 2006, the system appeared to be very efficient in reducing stormwater flow and bacterial transport to the ocean areas. Stormwater exported from the two outfalls combined was reduced by 97%, with brief overflows occurring at the M Ave. site (known as Site M) during only 5 of 25 storms measured. Nearly 3000 m (790,00 gallons) of stormwater were diverted into the dunes rather than discharging directly on the beach. The groundwater Enterococcus levels measured 8 m (25 ft) downslope of the systems ranged from 5 CFU/100 ml to 64 CFU/100 ml with a median of 5 CFU/100 ml at Site L, and ranged from 5 CFU/100 ml to 2,005 CFU/100 ml with a median of 26 CFU/100ml at Site M. These groundwater samples were significantly less than the stormwater Enterococcus concentrations that would have been exported from the outfalls (p<0.01). None of the groundwater samples at Site L exceeded the state’s Enterococcus standard, but six samples from the groundwater at Site M did (Bright, 2006; Burchell et al., 2007). The initial study of the system was considered a demonstration of a potential new BMP, so post-construction monitoring was to assess the feasibility of the practice. While the initial results of that level of monitoring appeared promising, the fate and transport of the bacteria in the dunes beneath the DIS was still not clearly understood. The increased groundwater Enterococcus concentrations observed particularly at Site M, the larger system, made it imperative that a more rigorous monitoring procedure be employed to determine if the DIS would have any negative Figure 1. The Dune Infiltration System at Site L during installation (left) and the well vegetated dunes 15 months after installation (right). effects as the groundwater migrated towards the ocean. Groundwater samples in the first study were collected only 8 m (25 ft) down-gradient of the DIS, leaving approximately 40 m (130 ft) of dune and beach for the groundwater to travel through before encountering the surf zone. We hypothesized early that bacteria levels near the system would likely be elevated, but would decrease as it moved laterally towards the beach. In May 2007, research at the site was intensified to test this hypothesis by studying the groundwater hydrology and bacteria levels in transects that extended from above the DIS system to the dune-beach interface, with added monitoring of a nearby dune system to serve as an experimental control. This paper will serve to summarize preliminary results obtained during the first 6 months of this study. Methods During July 2007, additional groundwater wells were installed up and downgradient of the systems to measure groundwater fluctuations and bacterial concentrations resulting from infiltration of stormwater into the DISs. Based on previous water table measurements and dune elevations that decreased as much as 2 m (6 ft) from Atlantic Avenue towards the beach, wells were installed 4-6 m (12-18 ft) deep. Wells were 5 cm (2 in) in diameter, and the bottom 0.6 m (2 ft) and 3 m (10 ft) of the water quality and water table wells respectively were screened and protected with two layers of drain sock. Each DIS had 1 transect of water table wells, and two transects of water quality wells downslope of the system, with one water table and water quality well upslope of the system. Figure 2 shows a general schematic of the DIS and the surrounding well locations. Additionally, wells were installed at upslope, mid, and at the dune-beach interface positions of a control dune. Water table measurements were logged continuously at 20 minute intervals with INFINITY (Infinities USA, Inc.) and HOBO (Onset Computer Corporation) water level recorders. Wells were surveyed initially and measured manually monthly to convert the readings into water level elevations. Rainfall was recorded using a tipping bucket rain gage and a HOBO event logger (ONSET Computer Corporation). 1 The use of trade names does not imply endorsement by North Carolina State University or ASCE. Figure 2. Schematic of the Dune Infiltration System and a general layout of the water table and water quality sampling wells. Water quality samples collected were delivered within EPA recommended holding times and temperature, and analyzed for Enterococcus (ASTM method #D6503-99) by NC Shellfish Sanitation and Recreational Water Section Laboratory in Wilmington, N.C. Stormwater samples entering each DIS were collected using an ISCO 6712 Portable Sampler connected to an ISCO 730 Bubbler Module (Teledyne Isco, Inc.) that used stage, slope and roughness of the pipe to calculate flow volumes and trigger the sampler. Groundwater samples were collected monthly with disposable bailers following purging of 3 well volumes. Results and Discussion Analysis of six-months of data collected at the DIS sites have revealed a number of interesting trends regarding groundwater hydrology and bacterial transport in the dune systems. Groundwater Hydrology Beneath the Dunes During the initial study there were only a few wells located about 8 m downslope of the systems, and there was no real strong water table response observed following infiltration events from smaller storms that would have indicated the extent of groundwater mounding beneath the systems. With the additional wells installed closer to the system, the water table response near the system has become more clear. Figure 3 shows and example of the water table response at Site L, the smaller system collecting stormwater from 1.9 ha (4.7 ac) watershed. Mounding beneath the DIS is easily observed following a 3.3 cm (1.3 in) rainfall event on December 16. X X X X X}, booktitle={World Environmental and Water Resources Congress 2008}, publisher={American Society of Civil Engineers}, author={Burchell, M. R. and Hunt, III, W. F. and Chescheir, G. M.}, year={2008}, month={May} }
 @inproceedings{lord_hunt_2008, title={Stormwater BMP Maintenance and Certification Program in North Carolina, USA}, ISBN={9780784409763}, url={http://dx.doi.org/10.1061/40976(316)13}, DOI={10.1061/40976(316)13}, abstractNote={Stormwater practices are being installed across the world and studies show they are not being properly inspected and maintained. If not properly maintained, stormwater practices will not perform as intended, but minimal guidance on maintenance procedures is available. In North Carolina, U.S.A., the North Carolina State University Cooperative Extension Service has developed a 1.5 day training and certification program that has certified approximately 500 design, local government, and landscape maintenance professionals and practitioners in stormwater practice inspection and maintenance. To date the response has been very favorable, as several communities now require the certification for anyone who designs and/or maintains stormwater practices. Officials with the state of North Carolina have incorporated designing for inspection and maintenance as part of their stormwater practice review.}, booktitle={World Environmental and Water Resources Congress 2008}, publisher={American Society of Civil Engineers}, author={Lord, William G. and Hunt, William F.}, year={2008}, month={May} }
 @inproceedings{lord_hunt_2008, title={Stormwater BMP Maintenance and Certification Program in North Carolina, USA}, ISBN={9780784410097}, url={http://dx.doi.org/10.1061/41009(333)64}, DOI={10.1061/41009(333)64}, abstractNote={Stormwater practices are being installed across the world and studies show they are not being properly inspected and maintained. If not properly maintained, stormwater practices will not perform as intended, but minimal guidance on maintenance procedures is available. In North Carolina, U.S.A., the North Carolina State University Cooperative Extension Service has developed a 1.5 day training and certification program that has certified approximately 500 design, local government, and landscape maintenance professionals and practitioners in stormwater practice inspection and maintenance. To date the response has been very favorable, as several communities now require the certification for anyone who designs and/or maintains stormwater practices. Officials with the state of North Carolina have incorporated designing for inspection and maintenance as part of their stormwater practice review.}, booktitle={Low Impact Development for Urban Ecosystem and Habitat Protection}, publisher={American Society of Civil Engineers}, author={Lord, W. G. and Hunt, W. F.}, year={2008}, month={Nov} }
 @inproceedings{traver_davis_hunt_cheng_2008, title={Stormwater Concepts — No Adverse Impact}, ISBN={9780784410097}, url={http://dx.doi.org/10.1061/41009(333)77}, DOI={10.1061/41009(333)77}, abstractNote={The scope and expectations of Stormwater Management have changed dramatically in the last few years, moving away from a purely flood control perspective toward a green infrastructure approach protecting the sustainability of our rivers and watersheds (PaDEP 2006). The first transition occurred when we as a profession realized that we could start to address water quality issues in our flood control based detention facilities, by creating naturalized basins or stormwater wetlands. Our next advance has been to integrate Low Impact Development concepts, such as pervious pavements, green roofs and bioretention, into the landscape to minimize the adverse effects of land form change and to address stormwater volume. As our profession becomes more confident in the performance and longevity of our BMP tools, we are again progressing, moving toward a "No Net Impact", or better stated, "No Adverse Impact" design goal.}, booktitle={Low Impact Development for Urban Ecosystem and Habitat Protection}, publisher={American Society of Civil Engineers}, author={Traver, Robert G. and Davis, Allen P. and Hunt, William F. and Cheng, Mow-Soung}, year={2008}, month={Nov} }
 @inproceedings{hunt_passeport_brown_2008, title={Water Quality and Hydrologic Benefits of Five Bioretention Cells in North Carolina}, ISBN={9780784409763}, url={http://dx.doi.org/10.1061/40976(316)6}, DOI={10.1061/40976(316)6}, abstractNote={Five bioretention cells were studied from 2004 through 2007 in central North Carolina. They were located in Charlotte (1), Graham (2), and Rocky Mount (2). The former three cells were located in the Piedmont and therefore were underlain by clayinfluenced soils. The latter two cells were located in the Upper Coastal Plain, which were sand dominated. The cells differed by vegetation cover, media type, media depth, and underdrain configuration. The Charlotte cell was 1.2 m deep and filled with a sandy-loam soil. It was drained by conventional underdrains and vegetated by trees and shrubs and covered by mulch. The Graham cells were 0.6 and 0.9 m deep, employed a proprietary soil comprised primarily of expanded slate fines, and had an upturn in the underdrain to create a sump to temporarily store water. The two cells were turf covered. In Rocky Mount, both cells were 0.9 m deep and used a sand fill media (98% sand). Both cells employed an upturned underdrain, but one cell was vegetated by turf grass and the other cell was vegetated by trees and shrubs and covered in mulch. Substantial data have been collected for the cells in Charlotte and Graham, while data collection in Rocky Mount is on-going. To date, all five cells, despite their many different design elements, have been shown to reduce nutrient loads and concentrations, and reduce outflow volumes, as compared to inflow volumes. Important implications of the research are a continued refinement of bioretention performance standards, confirmation that grassed systems perform comparably well to tree and shrub systems (at least in the short term), and the role of an upturned drainage system, particularly in a somewhat sandy in situ soil.}, booktitle={World Environmental and Water Resources Congress 2008}, publisher={American Society of Civil Engineers}, author={Hunt, William F. and Passeport, Elodie and Brown, Robert A.}, year={2008}, month={May} }
 @inproceedings{burchell_line_hunt, iii_wright_2007, title={Conversion of a Drainage Ditch to Constructed Wetlands to Treat Stormwater Runoff}, ISBN={9780784409275}, url={http://dx.doi.org/10.1061/40927(243)246}, DOI={10.1061/40927(243)246}, abstractNote={A drainage ditch near Laney High School in Wilmington, N.C., designed to collect runoff from athletic fields and parking lots and deliver it to Smith Creek, was converted to a constructed wetland in August 2005: The approximately 0.1 ha wetland collects and treats drainage water from a 12 ha watershed, 2.4 ha of which is impervious surface. The wetland was designed with a variety of elevation features and planted with over 15 species of wetland plants, to encourage sedimentation, biogeochemical transformations of nutrients associated with runoff, and ecological diversity. Retention times are estimated to be 3–4 days. As of summer 2006, the wetland was vegetated and on-line. Preliminary nutrient data indicate a 50% reduction in TN and TP concentrations, and a 40% reduction in TSS.}, booktitle={World Environmental and Water Resources Congress 2007}, publisher={American Society of Civil Engineers}, author={Burchell, M. R. and Line, D. and Hunt, III, W. F. and Wright, J.}, year={2007}, month={May} }
 @inproceedings{collins_hunt_hathaway_2007, title={Evaluation of Various Types of Permeable Pavements with Respect to Water Quality Improvement and Flood Control}, ISBN={9780784409275}, url={http://dx.doi.org/10.1061/40927(243)435}, DOI={10.1061/40927(243)435}, abstractNote={In many U.S. states, different permeable pavement types are considered to have the same capabilities in reducing runoff, and they are not credited with improving water quality. To test various permeable pavement designs, a parking lot consisting of four different types of permeable pavements and standard asphalt was constructed in Kinston, NC. The permeable pavement sections consist of pervious concrete (PC), permeable interlocking concrete pavers (PICP) with 8.5 % void space, PICP with 12.9 % void space, and concrete grid pavers (CGP), each covering a 1200 sq. ft. area with a 10 in. gravel storage layer. The purpose of this study is to evaluate and compare the effects of each pavement type on water quality and runoff reduction. Site analyses on every rainfall event began in March, 2006, and will continue through March, 2007. Preliminary results indicate significant (p<0.05) peak flow and volume reductions from all permeable pavements. Additionally, there has been little to no runoff observed from any of the pervious sections. Pollutant removal performance by the pavements has widely varied. As a result of this study, it is expected that the state of North Carolina will make a judgment on how much pollutant removal credit permeable pavement types should receive. Also, this study may be used to determine whether or not stormwater credit should vary based on pavement type.}, booktitle={World Environmental and Water Resources Congress 2007}, publisher={American Society of Civil Engineers}, author={Collins, Kelly A. and Hunt, William F. and Hathaway, Jon M.}, year={2007}, month={May} }
 @article{bean_hunt_bidelspach_2007, title={Evaluation of four permeable pavement sites in eastern North Carolina for runoff reduction and water quality impacts}, volume={133}, DOI={10.1061/(ASCE)0733-9437(2007)133:6(583)}, abstractNote={Four permeable pavement applications in North Carolina’s Coastal Plain were constructed and monitored to determine their effectiveness of reducing runoff quantity and improving water quality. Sites were either constructed of permeable interlocking concrete pavers (2), porous concrete (1), or concrete grid pavers (1). One site of each pavement type was monitored for runoff reduction for periods ranging from 10 to 26 months. Measured runoff depths from rainfall events over 50 mm were used to determine permeable pavement equivalent curve numbers for the sites, which ranged from 45 to 85. Only the two permeable interlocking concrete pavement (PICP) sites were monitored for water quality. Runoff and exfiltrate samples were intended to be collected, in addition to runoff monitoring, from the Swansboro PICP site. However, no runoff was produced during this study from the Swansboro PICP site for rainfall events up to 88 mm . From exfiltrate concentrations, nutrient retention was estimated to be 3.4 and 0.4 kg∕ha∕...}, number={6}, journal={Journal of Irrigation and Drainage Engineering}, author={Bean, E. Z. and Hunt, W. F. and Bidelspach, D. A.}, year={2007}, pages={583–592} }
 @inproceedings{hathaway_hunt_2007, title={Field Evaluation of Level Spreaders in the Piedmont of North Carolina}, ISBN={9780784409275}, url={http://dx.doi.org/10.1061/40927(243)579}, DOI={10.1061/40927(243)579}, abstractNote={Level Spreaders are commonly used in combination with riparian buffers as a stormwater Best Management Practice (BMP) in many parts of the United States. These systems have not been extensively studied in urban environments to determine if they can provide a long term water quality benefit. In winter 2005, 24 level spreaders were evaluated in the Piedmont of North Carolina. Detailed observations were made at 20 of these locations. The results of the study indicate that level spreaders may not be the versatile structure they are perceived to be. No level spreader — riparian buffer system was able to provide diffuse flow through the riparian buffer from the level spreader to the stream. Common causes for failure to maintain diffuse flow included: lack of maintenance (12 cases), poor design (11), riparian topography / content (11), level spreader lip not level (7), built with easily eroded materials (6), poor construction methods (3), and human interference (2). This field evaluation indicates that level spreader systems may need design revisions, construction guidance, and maintenance requirements before they continue to be used en masse.}, booktitle={World Environmental and Water Resources Congress 2007}, publisher={American Society of Civil Engineers}, author={Hathaway, J. M. and Hunt, W. F.}, year={2007}, month={May} }
 @article{bean_hunt_bidelspach_2007, title={Field survey of permeable pavement surface infiltration rates}, volume={133}, DOI={10.1061/(asce)0733-9437(2007)133:3(249)}, abstractNote={The surface infiltration rates of 40 permeable pavement sites were tested in North Carolina, Maryland, Virginia, and Delaware. Two surface infiltration tests pre- and postmaintenance were performed on 15 concrete grid paver lots filled with sand. Maintenance was simulated by removing the top layer of residual material 13-19 mm. Simulated maintenance significantly p0.007 improved the surface infiltration rate. The median site surface infiltration rate increased from 4.9 cm/h for existing conditions to 8.6 cm/h after simulated maintenance. Fourteen permeable interlocking concrete pavers PICP and eleven porous concrete PC sites were also tested. PICP and PC sites built in close proximity to disturbed soil areas had surface infiltration rates significantly p0.0014 and p0.0074, respectively less than stable landscape sites. Median PICP surface infiltration rates of each condition were 80 cm/h and 2,000 cm/h, respectively. Median PC surface infiltration rates with and without fines were 13 cm/h and 4,000 cm/h, respectively. This study showed that: 1 the location of permeable pavements; and 2 maintenance of permeable pavements were critical to maintaining high surface infiltration rates.}, number={3}, journal={Journal of Irrigation and Drainage Engineering}, author={Bean, E. Z. and Hunt, W. F. and Bidelspach, D. A.}, year={2007}, pages={249–255} }
 @inproceedings{hathaway_hunt_smith_bass_2007, title={Innovative Stormwater Treatment Practices in the Neuse and Tar-Pamlico Basins: A Partnership between the North Carolina Ecosystem Enhancement Program and the Biological and Agricultural Engineering Department at North Carolina State University}, ISBN={9780784409275}, url={http://dx.doi.org/10.1061/40927(243)570}, DOI={10.1061/40927(243)570}, abstractNote={Urbanization within North Carolina's watersheds and the need for proactive mitigation led to the establishment of the North Carolina Ecosystem Enhancement Program (EEP) in July 2003. The EEP is responsible for the majority of mitigation efforts throughout the state. These efforts include the restoration, enhancement, and preservation of streams and wetlands, as well as the creation of stormwater best management practices (BMPs) for the purpose of maintaining and improving water quality and riparian habitats across the state. This project involves a partnership between EEP and the Biological and Agricultural Engineering Department (BAE) at North Carolina State University for the purpose of locating, designing, and monitoring stormwater BMPs. In addition, local governments and the North Carolina Cooperative Extension Service assist in project site selection and development. Two large river basins in North Carolina, Neuse and Tar-Pamlico, have historic, significant degradation to water quality partially due to urbanization and agricultural practices. Primary pollutants within these basins include nitrogen and phosphorous. To change the trend of degradation, the State of North Carolina enacted regulations for nitrogen and phosphorous removal specifically for these basins. These regulations provided for the funding of the EEP Nutrient Reduction Program by authorizing impact fees.}, booktitle={World Environmental and Water Resources Congress 2007}, publisher={American Society of Civil Engineers}, author={Hathaway, J. M. and Hunt, W. F. and Smith, R. A. and Bass, K. L.}, year={2007}, month={May} }
 @inproceedings{smith_hunt_2007, title={Pollutant Removal in Bioretention Cells with Grass Cover}, ISBN={9780784409275}, url={http://dx.doi.org/10.1061/40927(243)581}, DOI={10.1061/40927(243)581}, abstractNote={North Carolina has spent considerable effort to improve water quality in the State and its estuaries. One area of focus has been stormwater runoff quality. Bioretention is often used to treat runoff from new developments and is retrofitted in areas where development has already occurred. Typical designs have trees and shrubs planted and mulch cover, which has become the design standard. There is significant interest in bioretention with grassed cover because maintenance could be less costly and because some owners consider them to be more aesthetically pleasing and usable. Some regulators are reluctant to allow grassed systems because of a lack of research data proving that they meet current standards for pollutant removal. The goals of this study were (1) to test the performance of grassed bioretention cells in removing nitrogen, phosphorous, metals and sediment and (2) to compare the pollutant removal between 2 identical grassed cells using induced storage zones with different fill media depths. An induced storage zone is a water storage layer at the bottom of the bioretention cell created by elevating the underdrain outlet above the bottom of the cell. A field system was built in the Piedmont of North Carolina for the study. Both cells lost volume during storm events through exfiltration, which decreased the volume of outflow through the underdrains. The induced storage zone caused an increase in the exfiltration volume, in some cases preventing any outflow from the underdrains, which improved the pollutant load reduction by the cells. Nutrient load reductions for TN were approximately 70 to 80%. Phosphorus load reductions were 35 to 50%. The higher load reduction estimates were associated with the cell with a greater media depth. Fecal coliform concentration removal was excellent for one cell, 97%. However, due to a limited number of storms collected (6), there was not a statistically significant finding. Subject Headings: Stormwater management; best management practice; water quality; nutrient loads; north carolina; hydrology; abatement and removal.}, booktitle={World Environmental and Water Resources Congress 2007}, publisher={American Society of Civil Engineers}, author={Smith, Ryan A. and Hunt, William F.}, year={2007}, month={May} }
 @inproceedings{jones_hunt_smith_2007, title={The Effect of Urban Stormwater BMPs on Runoff Temperature in Trout Sensitive Waters}, ISBN={9780784409275}, url={http://dx.doi.org/10.1061/40927(243)438}, DOI={10.1061/40927(243)438}, abstractNote={Urbanization can increase the temperature of coldwater stream environments by transferring heat from solar radiation, captured by pavement materials, to receiving water bodies through stormwater runoff. A number of aquatic organisms, including trout, are sensitive to elevated stream temperatures and temperature increases associated with urbanization have been shown to have a negative impact on the aquatic ecosystem. Research was conducted in regions of trout sensitive waters in Western North Carolina to determine, the effect that urban stormwater BMPs have on the thermal load of stormwater runoff at 4 bioretention areas, 1 stormwater wetland, and 1 wet pond. Water temperature and associated flows were remotely logged every 5 minutes at all BMP inlets and outlets, with additional temperature sensors located at specified depths and receiving waters. Analysis focused on flow and temperature reductions between inlets and outlets, as well as temperature changes within the BMPs due to diurnal fluctuations and storm events. Variations in temperature throughout the soil and water columns suggest the opportunity for modified outlet structures to reduce the thermal load discharged from BMPs. Results have also indicated the possibility of lowering runoff temperatures through conveyance in buried pipes. A comparison of the effect shading within the BMPs has on thermal load is also presented. An understanding of the temperature reduction mechanisms involved in urban stormwater BMPs should provide engineers with design criteria tos effectively mitigate the effect of thermal loads from stormwater runoff.}, booktitle={World Environmental and Water Resources Congress 2007}, publisher={American Society of Civil Engineers}, author={Jones, Matthew P. and Hunt, William F. and Smith, Jonathan T.}, year={2007}, month={May} }
 @article{hunt_jarrett_smith_sharkey_2006, title={Evaluating bioretention hydrology and nutrient removal at three field sites in North Carolina}, volume={132}, DOI={10.1061/(ASCE)0733-9437(2006)132:6(600)}, abstractNote={Three bioretention field sites in North Carolina were examined for pollutant removal abilities and hydrologic performance. The cells varied by fill media type or drainage configuration. The field studies confirmed high annual total nitrogen mass removal rates at two conventionally drained bioretention cells (40% reduction each). Nitrate-nitrogen mass removal rates varied between 75 and 13%, and calculated annual mass removal of zinc, copper, and lead from one Greensboro cell were 98, 99, and 81%, respectively. All high mass removal rates were due to a substantial decrease in outflow volume. The ratio of volume of water leaving the bioretention cell versus that which entered the cell varied from 0.07 (summer) to 0.54 (winter). There was a significant (p<0.05) change in the ratio of outflow volume to inflow volume when comparing warm seasons to winter. Cells using a fill soil media with a lower phosphorus index (P-index), Chapel Hill cell C1 and Greensboro cell G1, had much higher phosphorus removal than Gr...}, number={6}, journal={Journal of Irrigation and Drainage Engineering}, author={Hunt, W. F. and Jarrett, A. R. and Smith, J. T. and Sharkey, L. J.}, year={2006}, pages={600–608} }
 @article{hunt_apperson_kennedy_harrison_lord_2006, title={Occurrence and relative abundance of mosquitoes in stormwater retention facilities in North Carolina, USA}, volume={54}, ISSN={["1996-9732"]}, DOI={10.2166/wst.2006.625}, abstractNote={Throughout the 2004 mosquito season, 52 stormwater retention facilities were sampled to characterize the seasonal occurrence and relative abundance of mosquito species in relation to the structural complexity and biological diversity of the facilities. The three different types of facilities included standard wet ponds (n=20), innovative ponds (n=14), and wetland ponds (n=18). All retention structures were sampled at the beginning, middle and end of the mosquito season so that seasonal changes in mosquito production could be characterized. Overall samplings, mosquitoes were collected from 34% of the retention structures. Fourteen species representing 7 genera were collected, but only 5 species (Culex erraticus, Cx. territans, Anophelesquadrimaculatus, An. punctipennis and Uranotaenia sapphirina) were commonly collected in all three types of stormwater management facilities. In general, the seasonal prevalence and relative abundance of mosquito species did not vary among three types of retention structures. A significant association (P<0.01) between the presence of mosquito larvae or pupae and the absence of mosquitofish was found for innovative and wetland stormwater retention facilities but not for standard retention facilities (P>0.05).}, number={6-7}, journal={WATER SCIENCE AND TECHNOLOGY}, author={Hunt, W. F., III and Apperson, C. S. and Kennedy, S. G. and Harrison, B. A. and Lord, W. G.}, year={2006}, pages={315–321} }
 @inproceedings{clark_lenhart_de ridder_barrett_malina_hunt_jarrett_2006, title={Performance of BMPs}, ISBN={9780784408728 9780784471661}, url={http://dx.doi.org/10.1061/9780784408728.008}, DOI={10.1061/9780784408728.008}, abstractNote={Stormwater managers are increasingly faced with the need to address many potentially-conflicting issues as part of their activities. First, they need to control the potential flooding waters generated after urbanization. This has led to the use of detention facilities and control of peak flow rates to pre-development levels. However, these designs that focused on flow control for larger storms have been providing inconsistent performance for the control of other pollutants. Many other techniques, in addition to detention/sedimentation, have been proposed to alleviate these pollutant concerns. Stormwater ordinances/regulations and the development of TMDLs (with its subsequent need to control loadings to a stream) has driven the improvement of existing treatment technologies (often referred to as structural best management practices [BMPs]) and the development of new ones. Assumptions have made regarding the range of performance of these devices, based on the field data that currently exists, and as new data is submitted for publication, these new insights are added into the body of knowledge on BMP design and performance, specifically on the design needed to provide a specific performance.}, booktitle={BMP Technology in Urban Watersheds}, publisher={American Society of Civil Engineers}, author={Clark, Shirley E. and Lenhart, James H. and de Ridder, Scott A. and Barrett, Michael E. and Malina, Joseph F., Jr. and Hunt, W. F. and Jarrett, A. R.}, year={2006}, month={May} }
 @inproceedings{smith_hunt_jadlocki_2005, title={Conversion of an Urban Pond to a Water Quality Treatment Pond}, ISBN={9780784407929}, url={http://dx.doi.org/10.1061/40792(173)168}, DOI={10.1061/40792(173)168}, abstractNote={An aging urban pond in Charlotte, North Carolina was monitored for a period of one year prior to a water quality enhancement project for the pond and nearby drainage network. The 11 ha (27 ac) watershed for the .24 (ha (0.6 ac) pond consisted of mixed residential and commercial uses. Inflow and outflow composite samples were collected from August 2003 thru July 2004. Samples from 17 storms were analyzed for a suite of pollutants and event mean concentrations (EMC's) were determined for each storm. The pond was enhanced by the addition of a forebay, a detention component and a littoral shelf around its edge. In addition, a number of drainage improvements were made within the watershed to remove failing conveyances. The detention component of the pond was designed to store and hold the runoff associated with a rainfall of 2.54 cm (1 in) for a period of up to 24 hours. Water Quality results for the post construction period were not available at the time of this writing. During the pre-construction monitoring period, mean Total Kjeldahl Nitrogen (TKN) and Ammonium-Nitrogen (NH4-N) EMCs at the outlet were 32% and 19% higher than the inlet concentrations respectively. Mean Nitrate Nitrogen (NO3-N) and Total Nitrogen (TN) concentrations were shown to be 77% and 20% lower at the outlet. 16% and 63% reductions in Total Phosphorous (TP) and Total Suspended Sediments (TSS) concentrations respectively were observed from the inlet to the outlet. Copper, Lead and Zinc concentrations were reduced by 71, 39 and 49 % respectively. Statistically significant differences between the observed inlet and outlet mean concentrations was observed for all pollutants excepting TP and NH4-N.}, booktitle={Impacts of Global Climate Change}, publisher={American Society of Civil Engineers}, author={Smith, J. T. and Hunt, W. F. and Jadlocki, S.}, year={2005}, month={Jul} }
 @inproceedings{hunt_lord_smith_2005, title={Determining BMP Inspection and Maintenance Costs for Structural BMPs in North Carolina}, ISBN={9780784407929}, url={http://dx.doi.org/10.1061/40792(173)173}, DOI={10.1061/40792(173)173}, abstractNote={As stormwater structural treatment practices are becoming an increasingly larger part of the urban landscape, so, too, does the need to keep them in good working order. Eighteen agencies/firms which conduct stormwater practice maintenance were interviewed to determine costs for specific maintenance tasks of several stormwater practices. Data have been collected for bioretention areas, dry detention, green roofs, permeable pavement, sand filters, underground detention, wet ponds, and stormwater wetlands. As of early February 2005, data had been analyzed for three of the practices (dry detention, sand filters, and wet ponds). Initial analyses show that (1) maintenance costs were substantially higher than inspection costs, (2) economies of scale existed for maintenance costs within a practice, (3) sand filters were substantially more expensive to maintain an a per watershed acre (hectare) treated basis than wet ponds or dry detention, and (4) communities which plan to assume the responsibility of maintaining stormwater practices within its jurisdiction, will need to procure a considerable amount of money. Upon the study's completion in mid-March, five more practices will have been evaluated.}, booktitle={Impacts of Global Climate Change}, publisher={American Society of Civil Engineers}, author={Hunt, W. F. and Lord, W. G. and Smith, J. T.}, year={2005}, month={Jul} }
 @inproceedings{moran_hunt_smith_2005, title={Green Roof Hydrologic and Water Quality Performance from Two Field Sites in North Carolina}, ISBN={9780784407639}, url={http://dx.doi.org/10.1061/40763(178)99}, DOI={10.1061/40763(178)99}, abstractNote={Two green roofs were constructed and monitored in North Carolina's Neuse River Basin (WCC in Goldsboro and B&J in Raleigh). Data was collected from WCC from April 2003 to September 2004; B&J data collection began in July 2004. The hydrologic and water quality performance of two different green roofs were investigated. Each green roof retained a significant (p<0.05) proportion of the rainfall, peak outflows were significantly (p<0.05) reduced from the green roofs, and each green roof had substantial delays in runoff. Both concentrations and amounts of total nitrogen and total phosphorus increased from rainfall to green roof outflow and from the control roof outflow to green roof outflow. It was determined that the soil media, composed of 15% compost, was leaching nitrogen and phosphorus into the green roof outflow. This field study demonstrated the importance of green roof media selection in locations where nutrients are a concern.}, booktitle={Managing Watersheds for Human and Natural Impacts}, publisher={American Society of Civil Engineers}, author={Moran, A. C. and Hunt, W. F. and Smith, J. T.}, year={2005}, month={Jul} }
 @inproceedings{sharkey_hunt, iii_2005, title={Hydrologic and Water Quality Performance of Four Bioretention Cells in Central North Carolina}, ISBN={9780784407639}, url={http://dx.doi.org/10.1061/40763(178)72}, DOI={10.1061/40763(178)72}, abstractNote={Because bioretention areas have the ability to fulfill both landscape and water quality needs in a small area, they have received increased recognition as an integral part of Low Impact Development (LID); however, questions on design guidelines persist. Two paired, field-scale bioretention studies (Greensboro and Louisburg) have been conducted in North Carolina to study removal of phosphorus and nitrogen, hydraulic retention, the effectiveness of an induced saturated zone, and the impact of low P-Index fill media. Both bioretention pairs comprise nominally 5% of their respective watersheds and are planted with trees and shrubs. In Greensboro, one conventionally drained cell and one cell containing an induced saturated zone (previously termed anaerobic zone) of 0.45m were continuously monitored from June, 2002, to December, 2004. Lower outflow frequency was found for the induced saturated zone design. During outflow events, TP concentrations were significantly lower (P<0.01) than the conventional cell, although both designs increased outflow concentrations of nutrients. NO3 concentrations were reduced by 77%; however, TKN and NH4 concentrations were increased where the induced saturated zone was incorporated. In Louisburg, exfiltration, ET, and the significance of soil media for bioretention have been quantified by comparing outflow from two conventional cells constructed in winter of 2003 with non-agricultural soils. One cell was lined with 20 mil plastic; the other was unlined. During the summer of 2004, approximately 25% of inflow exfiltrated the cell, another 25% left via the cell’s underdrains and 50% of the inflow was released as ET. Also in Louisburg, the non-agricultural fill soils resulted in average concentration reductions of 40-53% TP, and 25-60% TN for 10 storms.}, booktitle={Managing Watersheds for Human and Natural Impacts}, publisher={American Society of Civil Engineers}, author={Sharkey, Lucas J. and Hunt, III, William F.}, year={2005}, month={Jul} }
 @inproceedings{apperson_hunt, iii_kennedy_harrison_lord_2005, title={Occurrence and Relative Abundance of Mosquitoes in Stormwater Retention Facilities in North Carolina}, ISBN={9780784407929}, url={http://dx.doi.org/10.1061/40792(173)209}, DOI={10.1061/40792(173)209}, abstractNote={Throughout the 2004 mosquito season, 52 stormwater retention facilities were sampled to characterize the seasonal occurrence and relative abundance of mosquito species in relation to the structural complexity and biological diversity of the facilities. The three different types of facilities included standard wet ponds (n = 20), innovative ponds (n = 14), and wetland ponds (n = 18). All retention structures were sampled at the beginning, middle and end of the mosquito season so that seasonal changes in mosquito production could be characterized. Overall samplings, mosquitoes were collected from 34% of the retention structures. Fourteen species representing 7 genera were collected, but only 5 species (Culex erraticus, Cx. territans, Anopheles quadrimaculatus, An. punctipennis and Uranotaenia sapphirina) were commonly collected in all three types of stormwater management facilities. In general, the seasonal prevalence and relative abundance of mosquito species did not vary among three types of retention structures. A significant association (P < 0.01) between the presence of mosquito larvae or pupae and the absence of mosquitofish was found for innovative and wetland stormwater retention facilities but not for standard retention facilities (P > 0.05).}, booktitle={Impacts of Global Climate Change}, publisher={American Society of Civil Engineers}, author={Apperson, Charles S. and Hunt, III, William F. and Kennedy, Shawn and Harrison, Bruce A. and Lord, William G.}, year={2005}, month={Jul} }
 @inproceedings{smith_hunt_jadlocki_eubanks_2005, title={Stormwater BMP Monitoring for Performance: The Charlotte Experience}, ISBN={9780784407929}, url={http://dx.doi.org/10.1061/40792(173)225}, DOI={10.1061/40792(173)225}, abstractNote={member ASCE, Extension Engineer, Department of Biological and Agricultural Engineering, North Carolina State University, Box 7625, Raleigh, NC 276957625;PH (919) 515-8595; Fax (919) 515-6772; email: jonathan_smith@ncsu.edu member ASCE, Assistant Professor and Extension Specialist, Department of Biological and Agricultural Engineering, North Carolina State University, Box 7625, Raleigh, NC 27695-7625; PH (919)515-6751; Fax (919)515-6772; email: wfhunt@ncsu.edu Water Quality Program Administrator, Engineering and Property Management, City of Charlotte,600 E. 4 street, Charlotte, NC 28202; PH (704)336-4398; Fax (704)336-6586; email: sjadlocki@ci.charlotte.nc.us 4 Water Quality Environmental Engineer II, Mecklenburg County Water Quality program, 700 N. Tryon Street, Charlotte, NC 28202; PH ( 704) 336-5446; email:}, booktitle={Impacts of Global Climate Change}, publisher={American Society of Civil Engineers}, author={Smith, J. T. and Hunt, W. F. and Jadlocki, S. and Eubanks, P. R.}, year={2005}, month={Jul} }
 @article{oliver-hoyo_allen_hunt_hutson_pitts_2004, title={Effects of an active learning environment: Teaching innovations at a research I institution}, volume={81}, ISSN={["1938-1328"]}, DOI={10.1021/ed081p441}, abstractNote={This paper describes a new approach for teaching general chemistry that combines lecture and laboratory into one seamless session and incorporates instructional methods supported by research-based findings. The results of a study that compared two instructional formats, conventional passive lecture and the student-centered, highly collaborative format known as cAcL2 (concept Advancement through chemistry Lab–Lecture), are also presented. Factors carefully controlled in this study include content material, time of day, time on task, and test format, scheduling, and grading. The results of the analysis of variance and the evaluation of the means conclude that the cAcL2 instructional method had a positive effect on student performance in an introductory chemistry class.}, number={3}, journal={JOURNAL OF CHEMICAL EDUCATION}, author={Oliver-Hoyo, MT and Allen, D and Hunt, WF and Hutson, J and Pitts, A}, year={2004}, month={Mar}, pages={441–U2} }
 @inproceedings{hunt_jarrett_2004, title={Evaluating Bioretention Areas from Two Field Sites in North Carolina}, ISBN={9780784407370}, url={http://dx.doi.org/10.1061/40737(2004)77}, DOI={10.1061/40737(2004)77}, abstractNote={Due to recent fish kills along the Mid-Atlantic coast, new regulations require all future land disturbing activities — including the urbanization or development of land — to be environmentally friendly. Consequently, stormwater management practices are being designed to remove nutrients, particularly nitrogen and phosphorus, before runoff reaches streams. One stormwater practice, bioretention, is gaining popularity in commercial development because it can easily be sited in the required natural areas of parking lot medians; however, the current design criteria used for bioretention have not been tested extensively. Pollutant removal, especially for species of nitrogen, has not been tested under various conditions. Currently used bioretention monitoring protocol assumes bioretention devices retain little water. Current designs do not reduce nitrate-nitrogen levels sufficiently, as bioretention is constructed without any zone designed to be saturated. For nitrate-nitrogen to be converted to nitrogen gas, thus enhancing total nitrogen (TN) removal, an anaerobic zone may be necessary. This research determined the effect of an anaerobic layer within bioretention devices on the concentrations and loadings of TN, nitrate-nitrogen (NO 3 -N), and other nutrient and pollutant species in stormwater runoff including ammonia-nitrogen (NH 3 -N), total kjeldahl nitrogen (TKN), total phosphorus (TP), ortho-phosphate (Ortho-P), zinc (Zn), iron (Fe), copper (Cu), lead (Pb), and total suspended solids (TSS). Four field bioretention areas were installed and monitored in two North Carolina cities. The field sites were used to test the pollutant removal abilities and hydraulic retention of bioretention devices that ranged in depth from 0.6 m (2 ft) to 1.2 m (4 ft) and were designed with or without an anaerobic layer. The field studies in North Carolina confirmed high annual TN mass removal rates at two conventionally drained bioretention cells (40% reduction). NO 3 -N mass removal rates varied between 75% and 13%. The presence of an anaerobic zone was tested at the Greensboro field site and significantly (p<0.10) reduced TP and Fe outflow concentrations. Annual metal mass removal rates at the Greensboro site were over 98% for both Zn and Cu and 81% for Pb. A very large mass of Fe (nearly 17 Kg from a 0.20-ha (0.5-acre) watershed was added to the storm sewer network by the bioretention cell. TP and TSS removal rates were highly variable from cell to cell.}, booktitle={Critical Transitions in Water and Environmental Resources Management}, publisher={American Society of Civil Engineers}, author={Hunt, W. F. and Jarrett, A. R.}, year={2004}, month={Jun} }
 @inproceedings{bean_hunt_bidelspach_2004, title={Study on the Surface Infiltration Rate of Permeable Pavements}, ISBN={9780784407370}, url={http://dx.doi.org/10.1061/40737(2004)72}, DOI={10.1061/40737(2004)72}, abstractNote={Asphalt surfaces have greatly increased the amount of pollutant-carrying runoff entering surface waters. To counteract this, permeable pavement can be installed to allow water to infiltrate, thus reducing runoff and acting as a filter. This study tested the surface infiltration rate of 27 permeable pavement sites in North Carolina, Maryland and Delaware. One of these sites in North Carolina was monitored to compare pollutant loads of asphalt runoff to those in infiltrate. Concrete grid pavers (CGP) and permeable interlocking concrete pavers (PICP) were tested with pavement ages ranging from six months to 20 years. Two infiltration tests were run on 14 CGP lots filled with sand. The initial test was on the existing condition of the surface and second test was run after the removal of the top layer of residue (1.3 - 1.9 cm) to simulate maintenance. Maintenance improved the infiltration rate on 13 of 14 sites. Analysis of the data showed that maintenance improves surface permeability at a confidence level of 99.8%. The median average infiltration rate increased from 5.0 cm/hr., for existing conditions, to 8.0 cm/hr after maintenance. Eleven PICP sites were also tested. Sites built in close proximity to loose fine particles had infiltration rates significantly less than sites free of loose fines. Averages of each condition are 60 cm/hr and 2000 cm/hr respectively. Even the minimum existing infiltration rates were comparable to those of a grassed sandy loam soil. Water quality data included in this study shows the results of six storms from June to October, 2003. With only a few storms to compare, only Zinc has been identified as having a statistically significant difference between infiltrate and runoff.}, booktitle={Critical Transitions in Water and Environmental Resources Management}, publisher={American Society of Civil Engineers}, author={Bean, E. Z. and Hunt, W. F. and Bidelspach, D. A.}, year={2004}, month={Jun} }
 @book{williams_keith_2003, title={Down the drain: How North Carolina communities manage stormwater runoff  [videorecording]}, publisher={Raleigh, N.C.: North Carolina State University}, author={Williams, S. and Keith, S.}, year={2003} }
 @article{hunt_2003, title={Introduction to the regulatory/policy/economics section}, volume={29}, ISSN={["0160-4120"]}, DOI={10.1016/S0160-4120(02)00188-5}, number={2-3}, journal={ENVIRONMENT INTERNATIONAL}, author={Hunt, WF}, year={2003}, month={Jun}, pages={287–288} }
 @article{leaf_verolme_hunt_2003, title={Overview of regulatory/policy/economic issues related to carbon dioxide}, volume={29}, ISSN={["0160-4120"]}, DOI={10.1016/S0160-4120(02)00161-7}, abstractNote={This is an overview of Session 2c dealing with the regulatory, policy and economic issues related to carbon dioxide and its impact on global climate change. The information is taken from the two papers presented in this session (the U.S. Perspective by Dennis Leaf and the European Perspective by Hans J.H. Verolme) and from the panel discussion that took place at the end of the session. The overview focuses primarily on the policy responses of both the United States (US) and the United Kingdom (UK) to changes in global atmospheric pollution. To a lesser extent, the progress of policy responses to these changes is discussed. The United Nations Framework Convention on Climate Change (UNFCCC) has been signed and ratified by over 180 countries. The UNFCCC contained no binding targets or timetables for emissions reductions. The Kyoto Protocol [United Nations. Kyoto Protocol to the United Nations Framework Convention on Climate Change. UNEP.IUC/99/10. Chatlelaine, Switzerland: United Nations Environment Programme's Information Unit for Conventions, for the Climate Change Secretariat, 1997] to the UNFCCC did contain targets and timetables for reductions of greenhouse gases on the part of developed countries. The US has signed but not ratified the Kyoto Protocol. The US has experienced some movement to reduce greenhouse gas emissions on the part of various levels of government, as well as the private sector. The UK's commitment to reducing green house gases is laid down in the UK Climate Change Programme 2000. The UK is a member of the European Union (EU). In this context, an example of EU-wide progress, the voluntary agreement with car manufacturers to reduce CO2 emissions in new vehicles, will be discussed. In addition, there will be some discussion on the UK CO2 trading scheme that created the first market in the world in April 2001. Overall, the policy process is constantly informed by scientific research. In the case of climate change, much of this work is carried out under the auspices of international scientific panels.}, number={2-3}, journal={ENVIRONMENT INTERNATIONAL}, author={Leaf, D and Verolme, HJH and Hunt, WF}, year={2003}, month={Jun}, pages={303–310} }
 @article{white_line_potts_kirby-smith_doll_hunt_2000, title={Jump Run Creek Shellfish Restoration Project}, volume={19}, number={1}, journal={Journal of Shellfish Research}, author={White, N. M. and Line, D. E. and Potts, J. D. and Kirby-Smith, W. and Doll, B. and Hunt, W. F.}, year={2000}, pages={473–476} }
 @article{hunt_skaggs_1997, title={Interpretation of "an average" in wetland hydrology analyses}, number={972033}, journal={Paper (American Society of Agricultural Engineers)}, author={Hunt, W. F. and Skaggs, R. W.}, year={1997}, pages={18} }