500 1 



400 



300 



5 

 o 



H! 200 



100 



Kiona (KM. 43) 



Sunnyside Dam (KM. 147) 



Umtonum (KM. 193) 



Cle Elum ( KM. 258) 



Eoston ( KM. 286) 



i '~' ^ 1 1 1 "~ i " ' -"'f '"' "I '"' " i'"^' " i '" " I "''"' 



May June 



"T 



July 



A^ 



Aug Sept Oct Nov Dec Jon Feb Mar. Apr May 



Figure 6.— Monthly flow of the Yakima River at Kiona, Sunnyside Dam, Umtanum, Cle Elum.and Easton, 



May 1957 to May 1958. 



supplement the river flow for irrigation in tlie 

 summer. During the spring and summer irri- 

 gation season, water releases maintain a 

 greater than normal volume in the upper 

 reaches, and irrigation diversions reduce the 

 volume of flow in lower sections. 



Irrigation and power diversions greatly 

 reduce water volume in two sections of the 

 Yakima River during the summer and fall. 

 The Wapato and Sunnyside Dams at km. 150 

 and 146 divert about one -half of the river 

 water into irrigation canals. The river be- 

 tween km. 67 and km. 53 becomes low in 

 summer and fall; the Prosser diversion ditch 

 removes 42 c.m.s. at km. 67 for electrical 

 power and irrigation and returns most of it 

 at km. 53. Although the depth at these locations 

 is adequate for the migration of fish, the 

 reduced flow results in a temperature rise 

 that creates a barrier to upstream migration 

 of salmon. 



The Naches River is the largest tributary; 

 it enters the Yakima River at km. 165. Like 

 the Yakima River, the Naches River is in- 

 fluenced by release of water from storage 

 reservoirs and diversion of water for irriga- 

 tion. It may contribute as much as 170 c.m.s. 

 to the Yakima River during spi'ing flood and 

 57 c.m.s. during the fall. Summer and winter 

 flows average below 28 c.m.s. 



Bryant and Parkhurst (1950) described in 

 detail the features of the river and the sites 

 used by salmon for spawning. Table 1 gives 

 the general features at our sampling sites. 



Table 1. — Hydrology and other characteristics of the Yakijna River at 

 sampling sites along the main stem in 1957 and 1558 



Location 



of 



site' 



Water 

 velocity^ 



Average 

 depth in 

 midstream 



Bottom 

 type^ 



Amount 



of 

 aquatic 

 vegeta- 

 tion* 



Amount 



of 

 shade* 



Distance upstream from the mouth of the river. 



M - Moderate, SI - Sluggish, Sw - Swift. 



B - Boulders, G - Qravel, M - l«ld, H - Rubble, Sa 



M - Minor, N - None. 



N - None, P - Patchy. 



Average 

 width 



Sand, Si - Silt. 



