The Survey 



4o Yakima R i vsr .— (Surveyed at various times, 1936-1947; 

 Hanavan, Baltzo, Whiteleather, Parkhurst, Morton, Bryant, Fulton^ and 

 Gangnark) . 



The Yakima River originates at Lake Keechelus on the east side of 

 Snoqualamie Pass in the Cascade mountains, at an elevation of 2,460 feeto 

 It flows 198 miles to Join the Columbia River approximately 335 miles 

 above the mouth of the latter and 10 miles above the confluence of the 

 Snake Rivero The main river has a total bottom area of over 22,000,000 

 square yards, of which only 6 percent was large rubble, 36 percent was 

 mud and sand, and the remaining 58 percent or approximately 13,000,000 

 Square yards was medium and small rubble,, Thd gradient is slight, 

 averaging only 11 feettper milee The river flow is regulated by several 

 resejrvoirs » Water storage is started in the impoundments at the con= 

 elusion of the irrigation season/ usually in Octobero In 1943, the 

 flow at Kiona, 29 miles above the mouth of the Yakima, varied from 1,300 

 CofoSo in mid October to 13,200 cef oSo in mid Aprilo The maximum re^ 

 corded discharge at this point was 71,100 OofoSe on December 2 3, 1933j, and 

 the minimum was 105 Cof oSo on September 11, 1906« 



In the lower 29 miles, from the river mouth to Kiona, Washington 

 there are excellent riffles and good pools » Most salmon have a tendency 

 to ascend farther upstream and this area is seldom used except by a few fall= 

 r\jn fisho Summer temperatures are often high in this section of the Yakimaj, 

 frequently reaching 80° Fe 



In the next 16 miles from Kiona to Prosser Dam the river flows through 

 a narrow valleyo Here the current is fairly swift and there is little spawn= 

 ing areao 



From Prosser up to the city of Yakima, Washington, a distance of 

 50 miles, the valley is wide and fairly flato The gradient is low, the 

 current is slight, the water is deep, (particularly below Granger) and 

 the bottom is usually covered with silt and algae o There are few &pawri= 

 ing riffles in tMs reach of the river that are satisfactory for salmon, 

 and during the simmer months the water is often too warm for salmon to 

 tolerate for any length of timec 



For most of the 40 mile distance between Yeikima and EileiXsb'Lirg 

 the river is in a deep oanyoh where the current is fas to There are only 

 a few good spawning riffles in this section. 



The 47 mile reach from Ellensburg to Easton Dam oontains the best 

 and most frequently used spawning areas of the entire river. The 

 temperatures are satisfactory, and there are good spawning riffles, 



7he construction of Roza Dam (see page 24) enabled counts on the 

 escapement to the upper Yakima to be made after 1940* The counts on 

 spring Chinook at this dam for each of the years from 1940 to 1947 

 inolusive were as follows^ 1011, 239, 521, 689, 242, 447, 989 and 



20 



