PROBLEMS FROM DEVELOPMENT 105 



extends also into the Hammond-Whiting area in Indiana, 

 and possibly northward along the lake shore to Milwaukee. 



At no place, however, are the deep sandstone aquifers 

 being unwatered. Even in the southwest Chicago industrial 

 district, where some pumps are set to lift water from depths 

 as great as 825 feet, the artesian pressure is sufficient to raise 

 the water above the top of the uppermost sandstone aquifer. 

 Throughout the industrial area these artesian aquifers are 

 still "full." 



The recharge area for the ground-water reservoir is in 

 south-central Wisconsin, more than 80 miles from the areas 

 of concentrated draft. So far as known, water from pre- 

 cipitation is available for replenishment in the recharge area 

 as fast as it can be transmitted toward the areas of draft. The 

 areas in which artesian pressures have been lowered signifi- 

 cantly extend at the most 30 to 40 miles out from the cen- 

 ters of heavy pumping, and it is unlikely that the pumping 

 has induced any appreciable increase in rate of flow from 

 the recharge area. The declining water levels show that 

 pumping has been in excess of this rate of transmission 

 through the sandstone, and partly at the expense of artesian 

 storage. Water levels in wells will continue to decline until 

 equilibrium is established either by decreased yield or by 

 increased movement of water from the recharge area. 



Some pumping lifts in this region are the greatest to be 

 found in the eastern half of the country. Many industries 

 are within areas served by public supplies taken from Lake 

 Michigan (the cities of Chicago and Milwaukee are the prin- 

 cipal examples) yet prefer to pump from wells. Whenever 

 the cost of ground water becomes excessive, these industries 

 can substitute the surface supplies, which are plentiful. The 

 summer temperature of the lake water, sometimes more than 

 70° F, makes it inferior to ground water for cooling and air 

 conditioning, but it may be possible to recharge the deep 

 aquifers through wells with cold lake water during the 

 winter and pump that water out when needed. 



As a means of relieving the shortage of municipal and in- 



