104 CONSERVATION OF GROUND WATER 



Chicago-Milwaukee Industrial Area, III. and Wis.™ 

 Ground water is used by many industrial plants in the Chi- 

 cago-Milwaukee industrial area and also furnishes munici- 

 pal supplies to several towns some distance from Lake Michi- 

 gan. It is estimated that pumping from wells averages about 

 110 million gallons a day. 



About 85 million gallons a day is pumped in the Chicago 

 area, of which 65 million is pumped from sandstone aqui- 

 fers 800 to 2,200 feet deep. The water in the sandstone was 

 originally under sufficient artesian pressure to flow at the 

 surface throughout the region, and the first deep well drilled 

 in Chicago (in 1864) had sufficient pressure to raise the water 

 80 feet above the surface. Even today there are some flow- 

 ing wells in southeastern Wisconsin, 30 or more miles from 

 the areas of heavy pumping. In the Chicago-Joliet area 

 pumping from deep wells started as much as 60 years ago; 

 pumpage was about 30 million gallons a day in 1915 and 

 65 million in 1940. There has been little change in rate 

 of pumping in the past decade. As greater and greater quan- 

 tities have been pumped, artesian pressures have declined 

 progressively, at an average rate of 6 to 8 feet a year for the 

 past 40 years. By 1949, concentrated draft in the southwest 

 Chicago industrial district and Joliet, 111., and at Milwau- 

 kee and Waukesha, Wis., had caused reductions in artesian 

 pressure of 400 feet or more, and in several other areas the 

 decline has been several hundred feet. Studies in the Chi- 

 cago area indicate that these separate cones of depression 

 have expanded and coalesced and that there is now an area 

 of more than 2,500 square miles where artesian pressures 

 have been reduced 100 feet or more. It is likely that this area 



39 References: "Control of Ground Water," Illinois Legislative Council, Pub- 

 lication 88, pp. 5-11, 1948. Also unpublished data of the 

 Illinois State Water Survey. 

 Drescher, W. J., "Results of Pumping Tests on Artesian Wells 

 in the Milwaukee-Waukesha Area, Wisconsin," Univ. Wis. 

 and U.S. Geol. Survey Rept., 1948. 

 Chicago Area W T ater Supply (a symposium), Midwest Engr., 

 vol. 2, pp. 6-21, February 1950. 



