Bishop Landfill, located approximately one mile south of Litchfield and the Long Branch Creek, is a 36-acre permitted sanitary landfill that was not certified as closed by the Illinois Environmental Protection Agency (Illinois EPA). Bishop Landfill operated from 1971 to 1987 and was permitted to accept only general refuse (trash), however, hazardous wastes were accepted without the operator acquiring the proper permits. The landfill was also filled beyond the permitted boundaries. The landfill has erosion problems, leachate seeps (rainwater that has infiltrated the landfill and mixed with the waste), and gas buildup. Illinois EPA completed an investigation of the current landfill conditions beginning in February 2003 and ending in December 2003. The investigation consisted of a land survey, cover thickness borings, and a landfill gas investigation. The investigation provided information on the cause of the leachate seeps, erosion and landfill gas problems. With this information gained from the investigation, Illinois EPA tasked Parsons Engineering Sciences, Inc. (Parsons) to develop corrective action strategies and evaluate them for technical feasibility and cost. Illinois EPA also sampled a nearby private drinking water well; no exceedences were detected above human health risk standards.