A study of ground water in the Franklin area, Tennessee, was undertaken to fill a growing need for information on ground-water occurrence in the carbonate rocks of central Tennessee. Fifteen drilling sites were selected that had one or more of the following characteristics: medium-to thick-bedded limestones within 200 feet of land surface, structural lows, significant streamflow gains and losses, elongated sinkholes, straight stream reaches, linear features or other surface indications of solution cavities at depth. The 15 test wells produced from less than 1 to about 600 gallons per minute and had an average yield of 68 gallons per minute, measured while pumping the wells with compressed air. The average driller-reported yield for the area is five gallons per minute. Specific capacities for the four highest yielding wells ranged from 0.6 to 357 gallons per minute per foot of drawdown after 8 hours of pumping at rates ranging from 70 to 225 gallons per minute. Additional drilling at two sites revealed extensive solution openings. At one site, drawdown in five observation wells did not exceed 8.5 feet during 48 hours of pumping at an average rate of 502 gallons per minute. Raw water in the test wells meets most drinking-water standards and is of rather uniform quality from well to well and throughout the year.
