FROM 



150 200 



MOUTH OF RIVER (KM.) 



Figure 3. — Water resistivity in 1957 and 1958 at sampling sites along the Yakima River, by time of sampling. 



80 

 40- 



. MARCH 3 TO 21,1958 



80-1 

 40 



80 

 S 40 



MAY 12 TO 20,1958 



-A/^ 



JANUARY I TO 21, 1958 



NOVEMBER 12 TO 22, 1957 



SEPTEMBER 18 TO OCTOBER 18, 1957 



JULY 15 TO AUGUST 7,1957 



APRIL 8 TO JUNE 20, 1957 



^V 



O 50 100 150 200 250 281 



DISTANCE FROM MOUTH OF RIVER (KM) 



Figure 4. — Water turbidity in 1957 and 1958 at sampling 

 sites along the Yakima River, by time of sampling. 



through a shallow canyon between km. 77 and 

 56. Above km. 225, coniferous forests pre- 

 dominate; below km. 225, sagebrush and 

 deciduous trees predominate along the river. 

 The wide valleys are intensively cultivated. 

 The elevation is from 640 m. at km. 281 to 

 96 m. at the mouth (fig. 5). Above km. 129, 

 the river drops 2.8 m. per kilometer; from 



-700 



uj 400- 



< 300 



100 150 200 



FROM MOUTH OF RIVER (KM.) 



Figure 5.— Elevation above sea level of the main stem of 

 the Yakima River from its mouth to 281 km. upstream. 



km. 129 to 72, 0.9 m. per kilometer; and 

 below this, 1.0 m. per kilometer. 



Average monthly flows ranged from 42 

 c.m.s. (cubic meters per second) at Easton 

 (km, 286) to 110 c.m.s. at Kiona (km. 43). 

 Extremes at Easton were 1 c.m.s. in October 

 to 76 c.m.s, in May 1957 (fig. 6). Extremes 

 at Kiona were 30 c.m.s. in June 1957 to 547 

 c.m.s. in May 1957. The spring floods in the 

 Yakima River depend on the melting of the 

 winter snowfall. The 1958 spring runoff was 

 below average because of a reduced snow- 

 pack. 



In some sections the river flow increases 

 with release of water from storage reservoirs; 

 in other sections the flow declines because 

 of irrigation and hydroelectric diversions. 

 The Easton Reservoir at km. 2 86, the Keechelus 

 Lake and Kachess Lake Reservoirs, above 

 km. 286, and the Cle Elum Lake Reservoir 

 store water during the winter and spring and 



