BEDROCK HIGH IN GLACIAL TERRAIN YIELDS GROUNDWATER SUPPLY AND CONSTRUCTION PROBLEMS FOR RESIDENTIAL AREAS, TIPPECANOE COUNTY, INDIANA

Thickness of Pleistocene glacial drift in Tippecanoe County averages over 100 feet, and bedrock outcrops are rare. However, a bedrock high trending northeast to southwest extends along the western edge of West Lafayette. Several housing sites located along this trend experienced problems, with the greatest occurring at Carriage Estates. With the presence of the Borden Siltstone, individual wells could not be developed on each home-owner's property nor could septic tanks be installed during construction. Excavation of sewer lines was also difficult and basements were not possible. Development of a community well supply was required and after geologic study, one was located about 2000 feet west of the site. A wastewater treatment plant to service the community was also constructed. Review of well records for the area indicates that housing sites to the northeast were impacted by this bedrock high. For these locations of shallow bedrock, groundwater supply was a major concern and several required a community well to provide a water supply. Problems at Carriage Estates should have been anticipated because a siltstone pit was located nearby and outcrops of siltstone were visible in the adjacent creek. Geologic constraints were not considered during planning of this subdivision.