Ground-water resources of the White River basin, Randolph County, Indiana

The two major aquifer systems in Randolph County, Indiana are sand and gravel and bedrock (limestone, dolomite, and shale of Silurian to Odovician age). The average thickness of the sands and gravels is 15 ft, and the aquifers are areally discontinuous. The bedrock aquifer underlies the entire study area and is estimated to be 150 ft in thickness.

Six pumping plans simulated in the two systems by a five-layer, digital, ground-water-flow model provide data for an assessment of the water-yielding potential of the systems. The model indicates that as much as 2.5 million gallons per day can be pumped from the aquifers at some locations. This and similar rates of pumping may cause drawdown greater than 5 feet in 10 to 50 percent of the study area. About half the stream reaches were reduced in flow by more than 10 percent by the simulated pumping. However, reaches where discharge exceeded more than 2 cubic feet per second were not affected to this degree. (USGS)