Ground water in the Dickson area of the western Highland Rim of Tennessee
A hydrologic study of the Dickson, Tenn., area provided additional information on the occurrence of ground water in the Mississippian carbonate rocks of the western Highland Rim. Twenty-six wells were drilled to determine the occurrence of ground water in relation to topographic position, regolith thickness, streamflow gains or losses, lithology of the underlying formations, and linear features. Yields of 26 test wells ranged from 0 to about 300 gallons per minute and averaged about 68 gallons per minute. Nine wells yielded 80 to about 300 gallons per minute; specific capacities ranged from about 0.71 to 12.7 gallons per minute per foot of drawdown. Seven of these nine wells yielded water from solution openings in the Warsaw Limestone. The other two wells yielded water from gravel and sand in the regolith. Aquifer tests were conducted on two wells. One well was pumped at an average rate of 350 gallons per minute for 72 hours with 39.77 feet of drawdown. The second well was pumped for 8 hours at 120 gallons per minute with 20.86 feet of drawdown. The water from both wells was of generally good quality. Water from one well had a dissolved solids concentration of 170 milligrams per liter. The dissolved solids in the water from a second well was estimated from specific conductance as about 160 milligrams per liter. Thick regolith and the presence of fine-grained limestone interbedded with coarse-grained limestone near the base of the regolith appear to be significant conditions for the development of solution openings that yield large amounts of water. Seventy percent of the test wells in which these conditions occurred yielded 80 gallons per minute or more.