118 CONSERVATION OF GROUND WATER 



The sandstone carries more water than is being pumped 

 and discharges it into the Minnesota and Mississippi 

 Rivers. This water could be developed by additional wells, 

 preferably near the recharge area and in any case away from 

 the cones of depression formed by existing wells. 



Oklahoma City, Okla. 50 Most of the ground water used in 

 the Oklahoma City area is pumped from bedrock aquifers 

 by industry and by several smaller towns for public supply. 

 About 6 million gallons a day is pumped from wells, some 

 of which are as much as 800 feet deep. The sandstone aqui- 

 fers have a relatively low permeability, and pumping has 

 therefore produced large and deep cones of depression. The 

 water in the sandstone is under artesian pressure originally 

 sufficient to raise water to within 100 feet of the surface in 

 Oklahoma City. During World War II, water levels in 

 wells throughout the area declined as a result of increasing 

 pumpage and by 1944 were as much as 230 feet below their 

 original positions in some wells, when more than 8 million 

 gallons a day was pumped for industrial use. With the con- 

 clusion of the war, the total pumpage decreased somewhat 

 due to closing of certain war installations, and water levels 

 in observation wells have not changed greatly in the past 

 five years. At. present it is considered that the rate of pump- 

 ing is not greater than the rate at which water can be trans- 

 mitted through the sandstone from the recharge area to the 

 wells. 



The public supply for Oklahoma City comes from the 

 North Canadian River and is stored in two reservoirs: Lake 

 Overholser with a capacity of 17,000 acre-feet, and the off- 

 stream Lake Hefner, with a capacity of 76,000 acre-feet. 

 At present rates of consumption those two reservoirs can 

 hold about a four-year supply for the city. Before the com- 

 pletion of Lake Hefner in 1944, however, the city faced 

 shortages of water whenever the flow of the North Canadian 



so Reference: Jacobsen, C. L., and E. W. Reed, Ground-water Supplies in 

 the Oklahoma City Area, Okla., Okla. Geol, Survey Min- 

 eral Rept. 20, 1949. 



