WATER QUALITY STUDIES IN THE 

 WENATCHEE RIVER BASIN 1/ 



INTRODUCTICN 



One purpose of this study was to deter- 

 mine and evaluate the physical and chemical 

 quality of the waters in the Wenatchee River 

 Basin in relation to the environment. The. 

 study was made prior to the proposed devel- 

 opment of two major hydroelectric projects, 

 so as to provide a basis of comparison, to 

 determine the effect they may have on the 

 water quality. Another purpose was to make 

 predictions, if possible, as to the changes 

 that might take place in the water quality 

 as a result of the impoundment due to these 

 hydroelectric projects. The final purpose 

 was to provide water quality data for evsilu- 

 ation of the Wenatchee River Basin, in 

 relation to its value in the preservation 

 of salmon resources of the Columbia River. 

 A biological study of these waters was made 

 by Sylvester and Ruggles _' in conjunction 

 with this investigation. It is not a part 

 of this report. 



GENERAL DISCUSSION OF FACTORS 

 AFFECTING WATER QUALITY 



Water, as it occurs in nature, is never 

 chemically pure; it Eilways has minute traces 

 of iaqjurities. Even rainwater picks up 

 small quantities of dissolved gsises and 

 solids, during its descent. The term water 

 quality refers to the properties and charac- 

 teristics imparted by the impurities, sind 

 to the type and quantity of mineral and 

 organic constituents preseilt. The impuri- 

 ties found in water can be divided into two 

 general classes: 



^/ Condensed from a thesis submitted in 

 partial fulfillment of the requirements 

 for the degree of Master of Science in 

 Civil Engineering. 



2/ "A study of the Wenatchee and middle 



Columbia River prior to dam construction*' 

 by Robert 0. Sylvester and Charles P. 

 Ruggles. University of Washington 

 (Seattle), Depeurtment of Civil Engineer- 

 ing and U. S. Fish and Wildlife Service. 

 Not yet published. 



1. Suspended impurities: those 

 present as individual insoljible particles, 

 such as clay, sand, and bits of organic 

 matter or living organisms. These particles 

 contribute turbidity to the water. 



2. Dissolved impurities: those that 

 intermingle with the water to form a solu- 

 tion, such as mineral salts and organic 

 substances. These constituents are evi- 

 denced by the color, taste, odor, or chemi- 

 cal properties they impart to the water. 



Carbon dioxide is soluble in water, 

 forming carbonic acid. Since all natural 

 waters usually contain some carbon dioxide, 

 the resultant water is actually an acid 

 solvent. This increased solvent power of 

 the water does much to increase the content 

 of dissolved minerals in surface and ground 

 waters and hence affects its quality. 



The water quality of a region always 

 reflects the conditions and uses of land 

 from which it drains. In attempting to 

 establish and evaluate the water quality in 

 the Wenatchee River Basin, a number of 

 factors which may influence it were conf 

 sidered. The factors and characteristics 

 of the drainage basin are listed below and 

 are discussed im imore detail in subsequent 

 pages. 



1. Topography 



2. Flow characteris- 



tics of rivers 



3 . Geology 



4. Soil mantle 



5. Climate 



6. Land use and 



vegetal cover 



7. Population 



8. Industry 



9. Ground water 

 10. Irrigation 



Topography 



The Wenatchee River drainage basin is 

 located in the southwestern extremity of 

 Chelan County in the central portion of the 

 State of Washington (fig. 1). It is bor- 

 dered on the west by the Cascade mountains, 

 on the north and east by the Entiat moun- 

 tains, and on the south by the Wenatchee 



