ABSTRACT
An investigation and closure program for a municipal and industrial solid waste landfill located in central Missouri has been successfully completed with regulatory approval and serves as a model for similar site closure programs in karst terrains. The landfill occurs within a mature dolomite karst system which includes numerous sinkholes, springs, cave systems, and gaining/losing stream areas. The investigation and closure of this site was conducted utilizing a focused set of innovative techniques including fracture trace analysis, natural-potential and azimuthal resistivity surveys, regional potentiometric data analysis, structural information, stream/spring gauging, monitoring well installations, and dye-tracing studies. Several fluorescent dye tracer tests were conducted in the vicinity of the landfill to better define groundwater flow directions, characterize conduit flow and identify discharge areas. Well-connected karst conduits were determined to be the structural features controlling the movement of groundwater in the vicinity of the landfill. Final landfill closure includes seep remediation, a landfill cap, closure of the on-site sinkhole, and monitoring. Landfill closure construction is anticipated to be completed in early 1995. This investigation and closure program represents a technically sound, cost-effective, and innovative approach to landfill closure within a karst aquifer system.
