around 10° C. or lower the pH 

 readings would be low. Thus, if 

 a sample warmed from 10° C. to 

 20° C. from the time of sampling 

 to the time of pH measurement, 

 the pH read would be above that 

 actually existing in the river. 

 Electrometric pH values should 

 be recorded with the sample tem- 

 perature at the time of pH mea- 

 surement . 



Dissolved Oxygen 



Recent laboratory studies in England 

 by Truesdale, et al. (18) have shown the 

 presently accepted (see reference Jl_9) dis- 

 solved oxygen saturation values at sea 

 level to be in error by as much as 4 percent. 

 The present values are high according to 

 these researchers (see below). 



Percent error in 

 Temperature present values (high) 



This report on the error in oxygen solu- 

 bility confirms field data where, in many 

 instances, a clean, turbulent river would 

 have an oxygen saturation of 96-97 percent 

 according to the old oxygen saturation 

 values. A stream of this type should be 

 essentially 100 percent saturated with oxy- 

 gen. Therefore, all dissolved oxygen 

 saturation values shown in this report 

 should be about 3.5 percent higher. If the 

 saturation values were corrected for eleva- 

 tion of the sampling station (barometric 

 pressure), the values would be increased 

 from about 4 percent for the Columbia River 

 at McNary Dam to about 6 percent for Nason 

 Creek. 



Station 38, Columbia River 

 Below Vantage 



This sampling station was along the 

 river bank at a location where the depth 

 sampler could be immersed in several feet 

 of water. Depth of sampler immersion along 

 the bank varied from 3-15 feet, depending 

 upon the river stage. Crab Creek discharges 



to the Columbia River about 1 mile above 

 the sampling station. This distance may 

 be insufficient for mixing during low river 

 stages. These circumstances undoubtedly 

 gave some values that were too high for 

 temperature, alkalinity, hardness, sulfates, 

 sodium and conductivity. 



Ammonia and Carbon Dioxide 



Values for these constituents are 

 approximate only, as the test techniques 

 used were not precise and because it was 

 necessary to make the ammonia analysis 1 

 to 3 days after the samples were collected. 

 Ammonia sajnples were preserved with sul- 

 furic acid when collected and refrigerated 

 when placed in the laboratory. 



PRESENTATION OF WATER QUALITY 

 DATA 



An important portion of this study 

 is the documentation of water quality prior 

 to dam construction. Average-monthly con- 

 stituent values observed at the river sta- 

 tions during the period of June 1954 through 

 March 1957 are given in tables 6-20. Fig- 

 ures 7-34 are plots of these constituent 

 values. Table 16 (page 27) summarizes the 

 water quality data observed in Nason Creek 

 by the U. cj. Fish aind Wildlife Service in 

 1940. Table 21 (page 70) presents water 

 pi'ality data obtained with depth in Lake 

 Wenatchee from June 1955 to February 1957 

 while table 22 (page 76) presents similar 

 data collected by the U. S. Fish and Wild- 

 life Service in 1939. Since average con- 

 stituent values (as given in tables 6-20) 

 do not indicate the range in values actually 

 observed, these ranges are given in table 

 23 (page 78) from minimum to maximum ob- 

 served values. This table also gives the 

 weighted- average constituent values for the 

 entire period of observation. Weighted- 

 average values take into consideration the 

 diluting or concentrating effect produced 

 by differences in stream discharge and they 

 are obtained by multiplying each constituent 

 value by the flow at the time of sampling, 

 getting the summation of these products and 

 dividing by the total flow in the period 

 of summation. 



Average-monthly water temperatures 

 from thermograph stations in the study area 

 are given in table 24 (page 86) together 

 with minimum and maximum values and diurnal 



2() 



