areas over the number necessary to aocommodate salmon ooxmted at 

 Lewiston in 1944 is not adequate. It will not cover the probable 

 maximum number of salmon which will return to the Trinity River 

 in some years. A fixed release schedule for salmon has the added 

 disadvantage of rigidity. It cannot bo quickly or effectively 

 changed when greater or lesser amounts of water and spawning 

 grounds are needed for the proper safeguarding of spawning stock* 



A fixed flow schedule such as the one proposed in Figure 12 

 requires a release of 120,500 acre-feet of water as measured at the 

 Lewiston Bridge, "ftie peak flow of 300 cubic feet per second would be 

 maintained only during the period of heaviest spawning. After spawning 

 is completed, the flow could be reduced to 200 cubic feet per second. 

 Such a flow will cover all gravel in which eggs have been deposited. 

 This flow should be maintained vintil the end of March when all but a 

 very few of the young salmon have left their nests. The river flow 

 should be not less than 150 cubic feet per second during April, May, 

 and June, to adequately provide for steelhead spawning and hatching. 

 The flotr should not be less than 100 cubic feet per second from July 

 1 to October 15. The svmuner flow schedule (April through October 15) 

 should insure the seaward migration of young salmon during April, May, 

 and June, and the upstream adult migration from the end of June until 

 the flow is increased to 200 cubic feet per second during the last 16 

 days of October to provide for the spring and summer runs that normally 

 start spawning at that time. 



The effect of this flow schedule on average river discharges below 

 Lewiston is shown in Figure 13 and Table 20. The comparison presimes 

 total diversion or storage of all other flow at Lewiston. The main 

 river flows during summer are relatively unaffected. Flows during 

 the steelhead spawning season are considerably reduced between Lewiston 

 and Burnt Ranch and may make the river bed more suitable for the spawning 

 of this species. 



Fish-tight counting structures should be built near the Union HLll 

 Pipe Crossing two miles below the Lowden dam site, and at a site to be 

 selected between Douglas City and the mouth of Browns Creek. These 

 barriers would divide the spawning grounds into throe areas of nearly 

 equal capacity and prevent a congestion of spawning fish in any one 

 area. A trap and sturdier fish barrier should be installed at or near 

 the present Lewiston weir to be used if it becomes necessary to transfer 

 fish. Tlie Lewiston barrier should be maintained as a means of preventing 

 \indesirable concentrations of fish immediately below the proposed Lewiston 

 dam where practically no spawning grounds exist. It may be desirable, 

 after further study, to locate tho Levdston barrier above the mouth of 

 Deadwood Creek to allow use of this small stream by steelhead trout. 



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