Hydrogeological Investigation of VOC Contaminated Private Wells Near Hudson, Wisconsin

Introduction: The purpose of this project was to compile hydrogeologic and geologic information for an area approximately five miles east of Hudson. This area has a signficant number of private wells contaminated with volatile organic compounds (VOC’s). As shown in Figure 1, a VOC contamination plume (Trichloroethylene levels used) exists around the Junker Landfill area and extends to the northwest. Concentrations are highest in wells south of the landfill and decrease toward the northwest. With the regional groundwater flow moving in a west-northwest direction (Borman, 1976) and a localized gradient which appears to approximate the regional flow, the landfill appears to be a contamination source. The plume illustrated in Figure 1 does not take into consideration the vertical dimension involved. There is variation not only horizontally from place to place as Figure 1 shows, but also vertically according to the depths at which the wells are installed. An index map with well locations is provided in Appendix A.

Less likely sources for the VOC contamination are spillage or dumping that may have occurred along the railroad tracks adjacent to the landfill or contamination from a 20 acre parcel which is the abandoned Town of Roberts landfill, located 0.9 miles due east of Junker’s. Although these potential sources exist, they appear to be secondary sources. Because of these potential sources, further investigation is necessary to identify the Junker Landfill as the sole source of contamination. Nor-Lake, Inc. located 2 miles west of Junkers was also considered as a possible source of VOC contamination in the study area but has recently been ruled out following a hydrogeological investigation at Nor-Lake (Soil Exploration Co., Nor-Lake Report, 1985).