to 2 J 200 Cofo>5o From August until December, during the fall spawning 



period, the flow is generally between 75 and 500 c«foSo During the 



period of low water in late summer the water temperature may exceed 

 70 Po except in the upper watershedo 



In the lower 17 mileB;, below the Tieton River^ the stream flows 

 through a broad valley that is bordered by semi -arid slopes, except 

 for the irrigated traotSo Here there is C'-Sva; i: naliy mere than one 

 channej., but the salmon usually pass over the available spawning 

 grounds in preference for those in the cooler headwaters o The 

 valley abore is considerably narrower and is bordered by steep 

 moderately wooded slopes o The mid^section of the river has many 

 large, clear^, deep resting pools, and riffle areas are frequento 

 There are extensive suitable spawning areas in the middle and upper 

 sections, and the river formerly supported large runs o A few spring 

 and summer chiiiook salmon and steelhead trout still enter the Naches 

 and its uppsr tributaries to spawn <, 



The only natural obstruction to fish is an 8 foot cascade located 

 1 mile above the Crow Creek tx^aii bridgej, about 45 miles up the river o 

 This is difficult for fish to pass during periods of low water. The 

 main obstacles to fish are the shallow or dry sections enoo-untered at 

 the height of the irrigation season, flashboards and downstreaai aprons 

 at several of the diversion damSp and superior attractions at one or 

 two diversion returns o 



The Old Union I rrigation Ditch takes off from the south bank i 

 miles a'bove the mouth of~THe Teaches River o It is one of the first 

 ditches buiit in the Yakima River system, has a capacity of 56 cofoS,, 

 and was screened in 1938 » In recent years it has been enlarged to 

 fxirnish water to the Cascade Lumber COo mill pond in Yakimaj, the 

 surplus being by=passed directly to the Yakima Rivero It is there^ 

 fore operated throughout the year, although the screens are taken 

 out at the end of the irrigation season and remain out all winter© 



The Fruitvale Diversion Ditch takes off from the south bank 3 

 mile3~upstreamo It lias a capacity of 110 CofoSo, and was screened 

 1/3 mile below the intake in 1938o A gravel and rock dam built along 

 the side of the river leads water to the intake and also shxmts most 

 of the water of lower Cofwlohe Creek into this canal o 



Tne Naches -Cowiche Irrigation Dam located 3 l/2 miles upstream 

 is a low concrete dam with an initial~drop of 3 feet onto a 15 foot 

 wide apron, and a second drop of 2 or 3 feet to the river belowo A 

 fishway i-s present at the south end of the damo Flashboards are 

 usually used during the irrigation season, and have at times been 

 placed across the upper end of the fishway as well. At such times 

 the St.' -cture is a barrier to fish» 



The Naohea-Qowicha Irrigation Ditch takes off at the south end of 

 the dam and has a capacity of 5o oofosT" It was screened in 1938 o 



30 



