Monday, 6 October 2008: 9:55 AM
George R. Brown Convention Center, 330B
Residential development continues to expand along the western boundary of West Lafayette, IN. Since the 1960s housing has developed slowly beyond the city and into rural Tippecanoe County. Outside the city limits residences require individual wells and septic tanks. Thickness of Pleistocene glacial drift typically exceeds 100 feet, and bedrock outcrops are rare. However, a bedrock high trends northeast to southwest along the western edge of the city. Housing sites here experienced major problems; the greatest at Carriage Estates. Near outcrops of Borden Siltstone, individual wells could not be developed nor workable septic tanks built. Sewer line excavation was also difficult and basements were ruled out. A community well was needed and after geologic study, it was located about 2000 feet away. A wastewater treatment plant was hastily constructed which has now been expanded for other areas. Well records indicate that sites to the northeast were also impacted by the bedrock high. Groundwater supply was a major concern and community wells were needed to provide water. Indian Creek and Hadley Lake parallel this bedrock high with the overall drainage affected. Geologic details provide insight into these relationships. Problems at Carriage Estates should have been anticipated as a siltstone pit is located nearby and outcrops occur in the adjacent creek. Geologic constraints were not considered during subdivision planning.