@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} }
 @article{lisenbee_hathaway_negm_youssef_winston_2020, title={Enhanced bioretention cell modeling with DRAINMOD-Urban: Moving from water balances to hydrograph production}, volume={582}, ISSN={["1879-2707"]}, DOI={10.1016/j.jhydrol.2019.124491}, abstractNote={Bioretention systems have become a leading stormwater control measure for mitigating urban hydrology. Although these systems have performed well in many site-scale field studies, less investigation has been directed toward effectively modeling these systems. This is critical, as modeling of bioretention systems provides an avenue for evaluating their effectiveness prior to devoting time and resources into installation. Many hydrologic models capable of simulating bioretention consist of lumped parameters and simplifications that do not fully account for fundamental hydrologic processes such as soil-water interactions. DRAINMOD has shown promise for obtaining detailed daily water balances within bioretention systems under continuous simulations. One significant advantage of DRAINMOD is that it uses the soil-water characteristic curve to account for fluctuations in soil moisture instead of assuming saturation; however, the model historically only produces daily outputs. For this study, DRAINMOD was modified to develop DRAINMOD-Urban, which allows high temporal resolution inputs and outputs, more closely matching the residence time of runoff in urban systems. DRAINMOD-Urban simulations of a bioretention cell in Ohio, USA, revealed that DRAINMOD-Urban could effectively produce hydrographs with a cumulative Nash-Sutcliffe Efficiency (NSE) of 0.60 for the 12 events that produced drainage over a 7-month monitoring period. Overflow was also modeled by DRAINMOD-Urban, but additional overflow data are necessary to derive conclusions about model effectiveness in predicting this hydrologic component. Input parameters previously calibrated for the DRAINMOD model did not translate well to DRAINMOD-Urban with the top-down approach applied in this study (NSE = 0.31 for drainage and NSE = −1.83 for overflow), but the bottom-up approach showed that parameters calibrated with DRAINMOD-Urban (NSE = 0.60 for drainage and NSE = −0.1 for overflow) could be used in DRAINMOD to obtain reasonable drainage volumes (25.6% error compared to measured values). This study suggests DRAINMOD-Urban is an effective tool for modeling bioretention hydrographs and demonstrates the importance of temporal scale in bioretention modeling by illustrating multiple model calibration approaches. Despite the promising results of this study, additional studies are recommended where validation of the model is performed at more sites, in particular for events with overflow. Further, sensitivity analysis of input parameters and comparison of DRAINMOD-Urban to other commonly used bioretention models would inform future modeling efforts.}, journal={JOURNAL OF HYDROLOGY}, author={Lisenbee, W. and Hathaway, Jon and Negm, L. and Youssef, M. and Winston, R.}, year={2020}, month={Mar} }
 @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{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{winston_hunt_2017, title={Characterizing runoff from roads: particle size distributions, nutrients, and gross solids}, volume={143}, number={1}, journal={Journal of Environmental Engineering (New York, N.Y.)}, author={Winston, R. J. and Hunt, W. F.}, year={2017} }
 @article{winston_anderson_hunt_2017, title={Modeling sediment reduction in grass swales and vegetated filter strips using particle settling theory}, volume={143}, number={1}, journal={Journal of Environmental Engineering (New York, N.Y.)}, author={Winston, R. J. and Anderson, A. R. and Hunt, W. F.}, year={2017} }
 @article{winston_hunt_pluer_2017, title={Nutrient and sediment reduction through upflow filtration of stormwater retention pond effluent}, volume={143}, number={5}, journal={Journal of Environmental Engineering (New York, N.Y.)}, author={Winston, R. J. and Hunt, W. F. and Pluer, W. T.}, year={2017} }
 @article{winston_al-rubaei_blecken_hunt_2016, title={A simple infiltration test for determination of permeable pavement maintenance needs}, volume={142}, number={10}, journal={Journal of Environmental Engineering (New York, N.Y.)}, author={Winston, R. J. and Al-Rubaei, A. M. and Blecken, G. T. and Hunt, W. F.}, year={2016} }
 @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{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} }
 @article{winston_lauffer_narayanaswamy_mcdaniel_lipscomb_nice_hunt_2015, title={Comparing bridge deck runoff and stormwater control measure quality in North Carolina}, volume={141}, number={1}, journal={Journal of Environmental Engineering (New York, N.Y.)}, author={Winston, R. J. and Lauffer, M. S. and Narayanaswamy, K. and McDaniel, A. H. and Lipscomb, B. S. and Nice, A. J. and Hunt, W. F.}, year={2015} }
 @article{borne_fassman-beck_winston_hunt_tanner_2015, title={Implementation and maintenance of floating treatment wetlands for urban stormwater management}, volume={141}, number={11}, journal={Journal of Environmental Engineering (New York, N.Y.)}, author={Borne, K. E. and Fassman-Beck, E. A. and Winston, R. J. and Hunt, W. F. and Tanner, C. C.}, year={2015} }
 @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} }
 @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} }
 @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{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} }
 @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} }
 @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} }
 @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{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{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} }
 @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{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{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} }
 @article{thermal mitigation of urban storm water by level spreader-vegetative filter strips_2011, volume={137}, number={8}, journal={Journal of Environmental Engineering (New York, N.Y.)}, year={2011}, pages={707–716} }
 @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} }