reservoirs and some of it had passed over 

 the fields. A large rise in all constitu- 

 ents is shown in figures 2k and 25. The 

 rise is particularly abrupt after the water 

 passes through the Potholes Reservoir. At 

 station 15, the water quality is very simi- 

 lar to that of the lower Snake and Yeikima 

 Rivers. This is to be expected since the 

 soil characteristics are similar. Thus, 

 we can expect that the future return flows 

 from the Columbia Basin Project will have 

 an effect on the Columbia River water qual- 

 ity similar to that produced by the Yakima 

 and Snake Rivers. It will be a less pro- 

 nounced effect than that of the Snake River 

 because the irrigated acreage will be 

 smaller. 



Crab and Rocky Ford Creeks: These creeks 

 were sampled because they Indicate the 

 quality of natural drainage waters from the 

 Columbia Basin area. They are both high in 

 dissolved constituents and quite euLkeiline. 

 Crab Creek, near its mouth (station 37) is 

 quite turbid, very warm in the summer, 

 highly alkaline, and has a relatively high 

 sodium £uad sulfate content. It can be 

 expected that Crab Creek water will improve 

 in quality as increasing eimounts of spent 

 and surplus irrigation waters are dis- 

 charged therein. 



MONTHLY CHANGES IN RIVER 

 TEMPERATURES 



Thermograph installations are main- 

 tained on the Columbia River main stem and 

 on its principal tributaries by the U. S. 

 Fidiand Wildlife Service and on the Wenat- 

 chee River system by the Chelan County 

 P.U.D. Limited thermograph records have 

 been obtained by the Washington Pollution 

 Control Commission on the Yakima River at 

 Donald, Chandler and Richland for the sum- 

 mer of 1955- Thermometer readings are 

 taken regularly by the U. S. Corps of 

 Engineers, the Bureau of Reclamation and 

 power companies at their major dams. At 

 Vancouver, Washington, the U. S. Weather 

 Bureau has been taken hand thermometer 

 readings of the Columbia River since 19^1. 

 Hand thermometer temperatures have been 

 obtained to an extensive or limited degree 

 in the Basin by the Hanford Engineering 

 Works, the Washington Pollution Control 

 Commission, Health Department and Depart- 

 ment of Fisheries, the U. S. Public Health 

 Service, the City of Portland and Wenatchee, 



Oregon State College and the University of 

 Washington. 



Table h lists the thermograph data 

 obtained by the U. S. Fish and Wildlife 

 Service and the Chelan County P.U.D. 



A compilation of average monthly 

 water temperatures for different streams 

 on similar years is of value for purposes 

 of comparison and to document river basin 

 temperatures at that time. Table 5 lists 

 the average monthly water temperatures for 

 the years, or portions of the years, of 

 195'4--195d at 34 stations in Ih rivers and 

 ci^eks of the Columbia River Basin where 

 temperature data were available. Tempera- 

 tures in the table followed by ein asterisk 

 are approximate only as they were calcu- 

 lated from limited hand thermometer read- 

 ings corrected for diurnal temperature 

 fluctuations. The following observations 

 can be made from a study of table 5 : 



1. The Columbia River discharges to 

 the ocean from October to February, water 

 that is from 1-5° F. colder than the water 

 at Coulee Dam for the same time. From 

 March to September, it discharges at a 

 temperature from 2-6° F. warmer than at 

 Coulee Dam. Highest water temperatures 

 are in August and lowest in March. During 

 a typical year, the temperature will vary 

 throughout the river from 36° F. at Coulee 

 Dam to b5° F. near the mouth. 



2. The Okanogein River discharges to 

 the Columbia River during the summer at a 

 lower temperature than it has at Oroville, 

 73 miles upstream. This is due, evidently, 

 to the discharge of colder stream and 

 ground water into the Okanogan below Oro- 

 ville . 



3. In the Wenatchee River system, 

 temperatures extend from the freezing level 

 in February to about 61° F. in August. 

 During the summer, water discharged into 

 the headwaters of the Wenatchee River from 

 Lake Wenatchee has about the same tempera- 

 ture as the water discharged to the Colum- 

 bia River, 55 miles downstream. The 

 normal summer warming of the river through- 

 out its course is offset by the inflowing 

 cooler Chiwawa River and Nason and Icicle 

 Creeks . 



k. Water temperatures in Crab Creek 

 are markedly influenced by discharges of 



Ui 



