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TESTIMONY OF THE IDAHO WATER USERS ASSOCIATION, INC. 



September 24, 1993 

 Page 4 



acre gross diversion. It also points out that the consumptive requirement 

 of crops on those lands is approximately 2-1/2 acre feet per acre leaving 

 some 4-1/2 acre feet not consumed by crops. Proponents of taking Idaho 

 water suggest that a significant part of that 4-1/2 acre feet could be 

 used for salmon recovery. They conveniei. ly ignore, however, further data 

 in the U.S. Geological Survey report that states that of the water 

 diverted for flood irrigation in the Snake River Basin, over 75% of that 

 water returns to the hydrologic system either as deep percolation to the 

 ground water system, evaporation to the atmosphere or return flow back to 

 3ie Snake River. The water that returns back to the Snake River moves on 

 down river, ultimately to the Columbia River and that water is used by the 

 salmon now. The water that percolates to the ground water system travels 

 through the Snake Plain Aquifer and issues in the Thousand Springs reach 

 from Twin Falls to King Hill, Idaho, in the wall of the Snake River canyon 

 and becomes a significant part of the Snake River flow at that point. 



Conservation in Idaho will not create water. That water is already 

 reentering the Snake River system. Approximately 36 million acre feet of 

 water is discharged each year at Lewiston in the Snake River. All the 

 conservation methods in the world will not increase the volume of water in 

 the Snake River at Lewiston. The only way that "new" water can be 

 obtained from Idaho to be discharged from our state is by taking irrigated 

 land out of production. Obviously we in Idaho will not stand for that 

 since our largest industry is agriculture. 



Even if large quantities of water were obtained from the upper Snake 

 River Basin, the channel configuration of the Snake River through the 

 middle Snake reach is such that flows in excess of 25,000 to 35,000 cfs 

 cannot be exceeded without flooding several towns along the banks of the 

 river. Additionally, once water is brought through die system, it can 

 only be shaped at one point, Brownlee Dam on the Snake River. The 

 hydraulic capacity of the dam is limited to about 30,000 cubic feet per 

 second unless water is spilled. If too much water is released from 

 Brownlee Reservoir, Idaho Power Company cannot follow it's summertime load 

 which is the primary source of electrical energy for pump and sprinkler 

 irrigation in the Snake Plain. The facts are that major irrigation 

 conservation on the Snake Plain will not increase the overall water 

 supply, it will decrease the flow issuing from the Snake Plain Aquifer at 

 Thousand Springs and will create major economic displacement without any 

 measurable positive impact on salmon recovery. We believe the proponents 

 of these proposals have separate agendas of developing instream flows in 

 the Snake River for other purposes as opposed to assisting in salmon 

 recovery. Hydrologic calculations show that even with the addition of one 

 million acre feet of water to the system in a 60 day period, velocity 

 through the lower Snake River would be increased less than one percent 

 with full reservoir pools. 



