nxillified by stream conditions on the main Walla Walla River. 



5-0» South Fork Walla Walla River .— (February Ih, 1935, and Jime 20, 

 1936; Burro-ws and Whiteleather.) Joins the north fork to form the main 

 Walla Walla River 56 miles above the mouth. It has a total length of 

 about 2U miles, of -which the lower 21.8 miles -was surveyedo The average 

 width near the mouth was from 35 to UO feet, and in the upper section about 

 15 feet* It was estimated that the stream was discharging about 60 c.f.So 

 at the time of survey, but it was reported that it may become completely 

 dry near the mouth during some summer seasons. 



Suitable spawning area was estimated to comprise 2U5>000 square 

 yards, or about 67 percent of the stream bed* Resting pools are adequate. 

 The stream could easily support large runs of cliinook salmon and steel- 

 head trout. A fairly good spring run of steelhead trout continues to 

 enter, but no salmon have been seen since 1925» Existing conditions on 

 the main Walla Walla River are largely responsible for this condition, 

 and constitute the limiting factor in realizing the potential value of 

 this stream to chinook salmon and steelhead trout. 



Water is taken from the stream by sixteen .' 'rigation and two 

 power diversions, none of Tdiich is screened. There are eight temporary 

 dams, passable at all times, in connection with the irrigation diversions, 

 and two permanent dams, each h feet high, in connection with the power 

 diversions. The lowermost power dam is operated by the city of Milton 

 Power Company, and is located about 1/2 mile above the mouth of the 

 stream. It has no fishway, but is a barrier to fish only during low 

 water stages. The unscreened diversion carries about 70 c.f.s. The 

 second power dam is owned by the Pacific Power and Light Company, and is 

 the uppermost struct\;Lre on the stream. It has an adequate fishway and 

 is passable at all times. The unscreened diversion carries 80-100 c.f.s* 

 All of the irrigation diversions are small, the total irrigation diver- 

 sion by the I6 ditches being slightly less than 15 c.f »s« All of the 

 dams and diversions are located in the lower 8-«iile section of stream. 



Present conditions on the main Walla Walla River greatly re- 

 duce the value of this stream for anadromous fish. 



5-0-(l)» Elbow Creek , 5-0-(2). Bear Creek , and 5-0-(3). Rough Creek .— 

 (June 23, 1936; Burrows and Whiteleather.) These are small, headwater tri- 

 butaries of the south fork of the Walla Walla. They are intermittent, 

 have steep gradient, and are of no value to salmon. 



5_0-(U). Skiphorton Creek .— (June 23, 1936j Burrows and Whiteleather.) 

 This is a small headwater tributary of the south fork with a total length 

 of about 2 miles, of which the lower 1/2 mile was surveyed. The width 

 varied from 7 to 15 feet, and the discharge was estimated at 10 c.f.s. It 

 is fed, maintaining a fairly uniform flow and low summer water temperatures. 

 Stiitable spawning area was estimated at only 1,100 square yards, and 

 constituted 25 percent of the stream bed. The stream bed contains numerous 

 large boulders. The gradient is steep above the terminus of the survey 

 triiere the stream is scarcely more than a series of cascades. A few steel- 

 head trout are said to enter, but the stream is of little possible value 

 to salmon. 



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