Transfer of Trinity River salmon from the main stream to 

 improved tributaries would not save any significant quantities of 

 water for the project. Minimum flows ranging between 100 and 200 

 cubic feet per second would have to be released from the Lewiston 

 dam to satisfy water users, to maintain the resident fish population 

 in the river below, and to provide adequate spawning grounds for the 

 salmon and steelhead populations which use the mainstream below 

 Lewiston* 



Artificial propagation 



A third method of aocomraodating the salmon normally passing 

 above the Lewiston dam site to spawn is artifioal propagation. As 

 yet, hatcheries have not proved themselves capable of maintaining 

 large runs of king salmon. Therefore, this method cannot be recommended 

 for the Trinity River at this time. 



Adequate sources of water suited to hatchery operation are very 

 scarce in the Trinity drainage below Lewiston. Many stream flows are 

 cold enough, but they are insufficient in volume to supply a hatchery 

 large enough to accommodate present runs of fish. Plenty of water of 

 fair quality could be obtained from the reservoirs to be built* How- 

 ever, such an arrangement would require that a hatchery be located 

 near the Lewiston dam site. The hatchery would need approximately 50 

 cubic feet per second of water for operation* In addition, sufficient 

 water would have to be released to the river to bring salmon and 

 steelhead to the hatchery* Quantities of water involved in this 

 latter operation would exceed 100 cubic feet per second. Very little 

 water would be saved to the project through artificial propagation* 



Maintenance Plans for Browns Creek Dam 



The construction of a dam at the Browns Creek site would out 

 off approximately 82 percent of the part of Trinity River used by 

 salmon for spawning. Optimum development below Browns Creek could 

 produce only 1,800 additional nests in the main river* Development 

 of the South Fork and Hay Fork, which are the only suitable spawning 

 tributaries below this dam site, would produce 2,300 additional salmon 

 nests* Together, these additional nests in the river, and tributaries 

 would provide for only 10,700 of a possible 21,000 Vsalmon that would 

 normally spawn above the dam* The only method known that would take care 

 of the remaining salmon that could neither spawn in the river nor in the 

 tributaries would be to construct a 30-^illion egg hatchery utilising 

 water fro* the reservoir. Such a plan could not be reoaranended because 

 of the very questionable outoone. 



l/__ Determined by estimating the natural salmon population between Browns 

 " Creek and Lewiston, using the number of nests at the normal spawning 



flow (150 c.f.s.) in that area, and adding the maximum number of 



salmon counted at Lewiston. 



69 



