Geohydrology of the upper part of the Galena-Platteville aquifer underlying a waste-disposal site near Wempletown, Illinois

The uppermost bedrock of the Galena-Platteville aquifer underlying a waste-disposal site near Wempletown, Illinois, is composed of dolomite of the St. James, Beecher, Eagle Point, and Fairplay Members of the Dunleith Formation of the Galena Group. Chert beds in these formations have a higher porosity than the dolomite.

Ground-water flow is from a drum-storage area to the west and northwest toward low points west and northwest of the drum-storage area and the topographic low at the intermittent stream south of the landfill area. The direction of ground-water flow at the landfill area is affected by seasonal changes in precipitation.

Calculated horizontal ground-water velocities ranged from 3.5 x 10-2 to 8.8 x 10-2 feet per day; the lowest value was in the vicinity of the landfill area. Horizontal hydraulic-conductivity values calculated from single-well aquifer tests ranged from 1.0 x 10-2 to 1.0 x 100 feet per day with an average of 4.0 x 10-1 feet per day.