PROBLEMS FROM DEVELOPMENT 91 



been to increase the discharge of springs. The famous 

 Thousand Springs and other large springs along the canyon 

 of the Snake between Milner and King Hill now discharge 

 considerably more water than 50 years ago. In 1902, before 

 irrigation, the total discharge of springs in this reach was 

 about 3,800 second-feet. The average inflow to the Snake 

 River between Milner and King Hill, derived chiefly from 

 these springs, increased to 4,900 second-feet by 1910, ranged 

 from 6,800 to 7,600 second-feet between 1920 and 1940, 

 and has exceeded 8,000 second-feet since 1942. This increase 

 results largely from return flow of irrigation water north of 

 the river. 



It has been estimated that under existing conditions of 

 replenishment from irrigated lands and from natural 

 sources, the ground-water reservoir under the Snake River 

 Plain above King Hill could yield 3,600,000 acre-feet an- 

 nually, and the reservoir below King Hill might yield an 

 additional 1 million acre-feet annually. The Minidoka 

 project of the U.S. Department of Interior proposes to 

 develop 241,000 acre-feet of this water over an 11-year 

 period, with close observation of the effect of this develop- 

 ment on the ground-water reservoir. The project involves 

 irrigation of about 65,000 acres by pumping from 150 or 

 more wells, each with a pumping capacity of 3 to 10 second- 

 feet. 



Some of the ground-water reservoirs in the humid East ap- 

 pear to be nearer to full development than several of those 

 described above, in spite of a notable advantage in precipita- 

 tion. Perhaps the best example is the Rahway River Valley of 

 New Jersey, which has a drainage basin of about 65 square 

 miles, and furnishes up to 30 million gallons a day of ground 

 water and 9 million gallons of surface water for industrial and 

 municipal use. In dry seasons, very little water passes the 

 lowest point of diversion. However, the outflow at other sea- 

 sons is an indication that the valley has not yet passed the safe 

 limit of development. 



