@article{harmsen_converse_anderson_hoopes_1991, title={A MODEL FOR EVALUATING THE 3-DIMENSIONAL GROUNDWATER DIVIDING PATHLINE BETWEEN A CONTAMINANT SOURCE AND A PARTIALLY PENETRATING WATER-SUPPLY WELL}, volume={8}, ISSN={["0169-7722"]}, DOI={10.1016/0169-7722(91)90009-P}, abstractNote={Effluent from septic tank-drainfields can degrade groundwater quality and contaminate nearby water-supply wells. Such groundwater contamination is a problem in the unsewered subdivisions of the sand plain of central Wisconsin, for example. To help planners minimize the risk of direct contamination of a water-supply well by a septic system, a model was developed to estimate the location of the critical dividing pathline between a rectangular contaminant source (the septic tank drainfield) and a partially penetrating pumping well. The model is capable of handling three-dimensional, transient flow in an unconfined, homogeneous, anisotropic aquifer of infinite areal extent, under a regional horizontal hydraulic gradient. Model results are in very good agreement with several other numerical and analytical models. Examples are given for which the safe, horizontal and vertical separation distances to avoid well water contamination are determined for typical central Wisconsin sand plain conditions. A companion paper (Harmsen et al., 1991) describes the application of this model, using a Monte-Carlo analysis, to study the variation of these separation distances in the Wisconsin sand plain. The model can also be applied to larger scale problems and, therefore, could be useful in implementing the U.S. Environmental Protection Agency's new well head protection program.}, number={1}, journal={JOURNAL OF CONTAMINANT HYDROLOGY}, author={HARMSEN, EW and CONVERSE, JC and ANDERSON, MP and HOOPES, JA}, year={1991}, month={Sep}, pages={71–90} }
 @article{harmsen_converse_anderson_1991, title={APPLICATION OF THE MONTE-CARLO SIMULATION PROCEDURE TO ESTIMATE WATER-SUPPLY WELL SEPTIC TANK-DRAINFIELD SEPARATION DISTANCES IN THE CENTRAL WISCONSIN SAND PLAIN}, volume={8}, ISSN={["0169-7722"]}, DOI={10.1016/0169-7722(91)90010-X}, abstractNote={Using a three-dimensional groundwater-contaminant tracking model a number of Monte-Carlo simulations were performed to estimate the mean and standard deviations of the separation distances and minimum well depth required to avoid contamination of a pumping water-supply well by a nearby septic tank-drainfield. The range of conditions simulated represent those found in the Central Wisconsin sand plain. A sensitivity analysis revealed that the separation distances and minimum well depth are most sensitive to variations in the horizontal hydraulic conductivity, anisotropy ratio and horizontal regional hydraulic gradient. The mean and standard deviations of the theoretical safe separation distances and safe well depth are presented as contour diagrams that can be used for design purposes. An example is given for which the design separation distances and minimum well depth are determined for a hypothetical subdivision in the Central Wisconsin sand plain.}, number={1}, journal={JOURNAL OF CONTAMINANT HYDROLOGY}, author={HARMSEN, EW and CONVERSE, JC and ANDERSON, MP}, year={1991}, month={Sep}, pages={91–109} }