of one to three degrees fahrenhelt In the 

 suBBer and a wanning effect of up to eight 

 degrees In the winter. 



A simpler approach to the temperature 

 coiQ>arlson is to assume that the flow €uad 

 air temperatures during the period 1934-38 

 and 1946-50 &re similar. With this assump- 

 tion, the average monthly water tempera- 

 tures at Rock Island can be compared by 

 obtaining the five year monthly averages 

 and plotting. This has been done in figure 

 kl which Indicates a warning effect frcm 

 Grand Coulee Dam construction of about 

 seven degree fahrenhelt maximum in the win- 

 ter and a cooling effect of about three 

 degrees nmYiminn In the svmmer. 



An evsLLuation of future temperature 

 changes that may take place in the Columbia 

 River as a result of dam construction is 

 contained in a later chapter of this report. 



In ccaparing upstream and downstream 

 water temperatures at a particular reser- 

 voir, it must be kept In mind that the 

 river water temperatures, in the absence of 

 a reservoir, would tend to Increase in the 

 same stretch during the sumner and perhaps 

 decrease during the winter. 



WATER QUALITY C(»<PARISONS 

 1910-11 TO 1952-56 



Selected Stations - Columbia and 

 Tributary Rivers 



In 1910, 1911 and I912, Walton Van 

 Winkle of the U. S. Geological Survey con- 

 ducted the first systematic study of sea- 

 sonal surface water quality characteristics 

 in the States of Oregon and Washington. His 

 work is published in U.S.G.S., W.S.P. 339 

 and 363 (49). At each selected sampling 

 station, daily samples of water were col- 

 lected and mailed to a laboratory where 10 

 consecutive samples were iinited. The ana- 

 lysis was made froa this composite. Analy- 

 tical and sample collection methods used by 

 the U. S. Geological Survey today are com- 

 parable to those used by Van Winkle except- 

 ing that samples are now composited by 

 volume according to their specific conduct- 

 ance. 



Between the time of V€Ui Winkle's work 

 and 1949, practically no water quality data 

 were obtained in the Columbia River Basin 



excepting for a few studies In limited £ireeus 

 like the Willamette Valley, Yakima Valley, 

 and a section of the lower Columbia River. 

 Since the purpose of this section is to note 

 any significant changes in river water qua- 

 Ity that have occurred since m£in ccssmenced 

 his multipurpose water uses, comparisons can 

 be made only between Van Winkle's data and 

 that obtained by the U. S. Geological Survey 

 and the University of Washington in very 

 recent years. A close, direct ccjmparison 

 cannot be made between these sets of data 

 since there is some difference in sampling 

 and analytical technique; some differences 

 in sampling points and time of day and fre- 

 quency of sampling; differences in the time 

 of sample storage before analysis; and be- 

 cause the stream flows were not the same in 

 the two time periods under comparieon. 

 Figure 42 illustrates the change in water 

 quality at a particuleo" iKJint during the 

 course of a year's sampling with changing 

 rates of river discharge. It will be noted 

 that in general, the constituents are high- 

 est during low discharge and lowest during 

 periods of high stream discharge. Curves 

 for other locations (figs. IO-I9, reference 

 50) will show less or more marked changes 

 with a change in flow. These quality changes 



COMPARISON OF FLOW RATE AND WATER QUALITY 

 COLUMBIA RIVER o» MARTMILL. 1952- 1953 



U S G S DATA 



■ UC 5E. QCl lOV OEC 



FIG. 42 



b7 



