solids - ^k; sulfate - 65j calcium plus 

 oagoeslua - 69; sodium plus potassium - 89; 

 silica - 21; color - (-) 55; nitrate - 36O; 

 chloride - 82; and Iron - 29. 



Okanogan River at Okanogan and near 

 mouth, Figure 51. Table 19 : 



The 1910-11 U.S.O.S. data were col- 

 lected at Okanogan, 25 miles above the 

 mouth where the 195^^-55 data were obtained 

 by the University. U.S.G.S. data have not 

 been collected fron the Okanogan River In 

 sxifflclent quantity to be used In these 

 ccmparlsons. The University data used was 

 not collected as frequently as the I9IO-II 

 data and, therefore, the comparison must 

 be very general. There are no significant 

 trlbutaurles betvreen Okanogan and the river 

 mouth. The Okanogan River was not gauged 

 in 1910-11. Three hundred and twenty-five 

 thousand acre -feet of storage were added 

 to Lake Okanogan In 1915* 



Irrigated acreage has increased 175 

 percent, population 230 percent, and an 

 Industrial waste population equivalent of 

 15,000 persons has been added to the water- 



shed during the kO-yeaT comparison period. 

 While these percentages are high, the total 

 population and irrigated area are not rela- 

 tively large for a river basin with a mean 

 discharge of 2,800 c.f .s. From figure 51 

 and table 19, & general increase in values 

 during the UO-year period can be noted with 

 the exception of turbidity and sodium plus 

 potassium. 



Wenatchee River, Figures 52 and 53 , 

 Table 20 : 



In I9IO-II, the Wenatchee River was 

 sampled at Cashmere by the U.S.G.S. and in 

 1954-56 at Sleepy Hollow by the University. 

 Sleepy Hollow is 5 miles downstream from 

 Cashmere suid there axe no intervening tri- 

 butaries of any consequence. Ibilverslty 

 data, although limited in frequency of 

 sampling, is used for the later period as 

 insufficient U.S.G.S. data are available. 



The Wenatchee River watershed with a 

 mean nnnitaT flow of 2,900 c.f.s. has the 

 smallest irrigated acreage and population 

 (with no significant Industrial waste con- 

 tribution) of any of the streams under 



OKANOGAN RIVER AT OKANOGAN I9I0-I9II -1^" 

 OKANOGAN RIVER AT MOUTH 1954-1955 ^ ^ 



TURBIDITY 



SULFATE (SO^ 



TOTAL SOLIDS TOTAL HARDNESS TOTAL ALKALITY 



FIG. 51 



76 



