variations. Average temperatures listed in 

 tables 6-20 are averages of water tempera- 

 tures taken at the time of sample collection. 

 Table 25 (page 90) lists the water tempera- 

 tures with depth observed in Lake Wenatchee 

 on the sampling dates shown in the table. 

 Ice and snow prevented lake sampling during 

 the winter months and high winds frequently 

 made lake sampling difficult or impractica- 

 ble. Table 28 (page 95) lists the thermo- 

 graph stations established in the Wenatchee 

 River Basin by the Chelan County P.U.D. and 

 by the U. S. Fish and Wildlife Service. 



Air temperatures affect the water 

 quality and the amount of flow in these 

 snow- fed streams. Air temperatures from a 

 nearby U. S. Weather Bureau station (20) 

 are shown in tables 6-20 as mean-monthly 

 temperatures . 



ANALYSIS OF DATA 



General Discussion 



The quality of water at all stations 

 sampled was satisfactory for aquatic life 

 (within limits of quality tests that were 

 made and of known fish tolerance to toxic- 

 ity) with the exception of summer water 

 temperatures that were above 65° F. in the 

 Snake River, lower Yakima River, Crab Creek 

 and the Columbia River from Pasco to below 

 McNary Dam. It has been demonstrated (35) 

 that the virulence of the indigenous myxo- 

 bacterium Chondrococcus columnaris greatly 

 increases when water temperatures exceed 

 65° F. These bacteria cause lesions in 

 fish and have resulted in the destruction 

 of large numbers of fish when water tempera- 

 tures were above 65° F. With the exception 

 of Crab Creek, the water quality at all 

 stations observed would be satisfactory for 

 public water supply if the supply system 

 incorporated facilities for removal of tur- 

 bidity, color and bacteria (31). 



Dissolved oxygen values were high, 

 usually near or above saturation. All 

 streams were alkaline with the exception 

 of those in the Wenatchee River Basin above 

 Leavenworth where pH values below 7.0 were 

 observed for a portion of the year. Carbon 

 dioxide and ammonia values were low and 

 usually insignificant in magnitude. The 

 lower Yakima River, Snake River and Crab 

 Creek have relatively high constituent values 

 for alkalinity, hardness and sulfates. 



Analyses for zinc, lead, silver and 

 manganese were made only in the period of 

 June 1954 to May 1955. These elements were 

 not found in any of the samples tested. 

 Traces of copper and aluminum were found 

 at all sampling stations. Sodium values 

 were high in Crab Creek (up to 135 p. p.m.) 

 and relatively high in the Snake River (up 

 to 38 p.p.m.). A discussion of the signifi- 

 cant water quality characteristics of each 

 of the sampling stations follows. 



Columbia River at MaNary Dam 

 Table 6, Figures 7 and 8 : 



Water quality and flow at this sta- 

 tion are influenced by the Sanke and Yakima 

 Rivers tributary 32 and 43 miles upstream 

 respectively. The Snake is a large river 

 and in May, the month of its peak flow, the 

 discharge is greater than half that of the 

 Columbia at the point of confluence. In 

 May, the Yakima River discharge is but 2 

 percent of that in the Columbia. Peak flow 

 at McNary Dam occurs in June when dissolved 

 constituents, such as those producing hard- 

 ness and alkalinity, are at a minimum for 

 the year. Turbidity and color would nor- 

 mally be highest in June. However, they 

 were greatest in March during this sampling 

 period because of 1957 construction work 

 in the Snake River for the Ice Harbor Dam. 

 Water temperatures rose from a low of 32° 

 F. in January and February to a high of 

 69° F. in August and September (see table 

 24, page 86). The river water was super- 

 saturated with dissolved oxygen from May 

 through September. Carbonate alkalinity 

 was observed from August through October, 

 a period when irrigation return flows were 

 markedly influencing water quality in the 

 Snake and Yakima Rivers. Calcium^ magnesium, 

 sulfates, sodium and potassium have their 

 greatest concentration during the period 

 of low-water flow from October to March. 



Snake River at Mouth 

 Table 7, Figures 9 and 10 : 



Average-monthly water temperatures, 

 dissolved oxygen saturation and carbonate 

 alkalinity (with pH) were greatest during 

 the month of August. Water temperatures 

 of 79° F. (table 24) have been observed in 

 the Snake as daily maximums. The average- 

 monthly August water temperature in the 

 period of 1954-1956 was slightly over 72° 

 F. High dissolved oxygen saturation 

 values (average of 119 percent, maximum of 



91 



