112 CONSERVATION OF GROUND WATER 



a day. Some wells have been pumped for nearly 50 years, 

 and in that period there has been a progressive decline of 

 water levels in many wells. 



Conditions are especially serious at Norwood, where 

 water levels have declined more than 80 feet in 40 years. 

 There a large proportion of the water has been taken from 

 storage, and more than half the aquifer has been drained. 

 At Ivorydale, conditions are almost as bad, for water levels 

 have dropped as much as 75 feet in 55 years, and in places 

 only the lower third of the aquifer is still saturated. At 

 Carthage also the rate of pumpage is considerably in excess 

 of the replenishment. At all three places the yields of wells 

 have decreased as the pumping lifts increased and will be 

 reduced further as water levels approach the bottom of the 

 aquifer. At Wyoming there remains a greater thickness of 

 saturated material, but pumpage has been greater than at 

 the towns farther south, and water levels have declined as 

 much as 25 feet in 10 years. Farther north in Mill Creek 

 Valley, at Lockland and Sharonville, water levels have de- 

 clined somewhat due to pumping, but there is considerable 

 recharge from Mill Creek in flood, resulting in appreciable 

 replacement of storage in some years. 



Studies of the geology and hydrology have shown the 

 reason for the large storage but comparatively low perennial 

 yield of the ground-water reservoir in Mill Creek Valley 

 and Norwood trough. Those broad valleys were formed and 

 later abandoned by the Ohio River, and the ground-water 

 reservoir is thus in the coarse sand and gravel deposited by 

 a major stream. Recharge to this reservoir is limited now 

 to quantities that infiltrate from precipitation on the valley 

 and from small streams such as Mill Creek (total length 

 about 25 miles). In the southern part of Mill Creek Valley, 

 the ground-water reservoir is buried under impermeable 

 clay. The replenishment to the wells at Wyoming, Carthage, 

 Ivorydale, and Norwood is limited, therefore, not only by 

 the recharge beyond the limits of the clay cap but by the 

 rate at which water can be transmitted through the aquifer 



