PROBLEMS FROM DEVELOPMENT 117 



Madison, Wis., 48 pumps about 12 million gallons a day 

 from wells for municipal supply. The static artesian pres- 

 sure in the center of the cone of depression has declined 

 about 55 feet since 1882, but pumping levels in the widely 

 separated municipal wells have not dropped appreciably 

 since 1922. 



Minneapolis and St. Paul, Minn.* 9 The Twin Cities ob- 

 tain their public supplies from surface water, but probably 

 more than 50 million gallons a day is pumped from private 

 wells, chiefly for air-conditioning and industrial use. Prac- 

 tically all this ground water comes from a sandstone more 

 than 300 feet below the surface in the areas of greatest draft. 

 As a result of pumping, artesian pressure has declined about 

 60 feet in the heart of Minneapolis, which is 10 miles from 

 the recharge area, and as much as 100 feet in the South St. 

 Paul industrial district, twice as far from the recharge area. 

 The shape of the cone of depression under Minneapolis is 

 indicated by declines in artesian pressure amounting to 30 

 feet at distances of 2% miles from the downtown district, 

 and only a few feet in the suburbs; in the part of the re- 

 charge area nearest to Minneapolis the water table has 

 dropped slightly, but no decline has been shown in wells 

 near Lake Minnetonka, farther west along the recharge 

 area. Within this cone of depression the rate of decline has 

 been less in the past decade than it was prior to 1940, and 

 water levels were practically the same in April 1950 as in 

 April 1949. Thus, inflow appears to be about equal to the 

 rate of pumping draft. In St. Paul, water levels declined as 

 much as 50 feet prior to 1925, when the city depended upon 

 wells for part of the municipal supply, but have risen some- 

 what in the past two decades. In South St. Paul, water levels 

 are still dropping at appreciable rates, partly because of in- 

 creasing draft. 



*s Reference: Foley, F. C, Personal communication. 



49 Reference: Bradley, Edward, "Artesian Water Supply of the Twin Cities 

 Basin," Minn. Geol. Survey, Mimeo. rept., 1949, 18 pp. 



