WATER QUALITY STUDY OF WENATCHEE AND MIDDLE COLUMBIA RIVERS 

 BEFORE DAM CONSTRUCTION 



ABSTRACT 



A water quality study was made in the Wenatchee River Basin and on the Columbia River 

 from Beebe (near Chelan, Washington) to McNary Dam for the piarpose of ascertaining the effect 

 proposed dam construction will have on water quality and its relation to aquatic life. Water sam- 

 ples were collected during the period from June 1954 to April 1957. They were analyzed for the 

 common constituents and for other constituents that might affect aquatic life. These data are 

 summarized and discussed. They are compared with similar data collected in 1910-11. 



INTRODUCTION 



Public Utility District No. 1, of 

 Chelan County, Washington, and Public 

 Utility District No. 2, of Grant County, 

 Washington, are developing hydroelectric 

 facilities on the Columbia River. Federal 

 Power Commission licenses for these facil- 

 ities direct the sponsors to carry on pro- 

 ject planning in cooperation with Federal 

 and State agencies concerned with the fish- 

 ery resource. The United States Fish and 

 Wildlife Service, as a Federal agency, has 

 worked with the Public Utility Districts 

 in the planning of these power facilities 

 so far as they might affect the fishery. 

 This study has been supported by these 

 Public Utility Districts through the U. S. 

 Fish and Wildlife Service, which in turn 

 contracted for the study through the Uni- 

 versity of Washington and its Department 

 of Civil Engineering (1). 



Existing and proposed dams in the 

 vicinity of this study area are shown in 

 figure 2 (page 2). The Chelan P.U.D. pro- 

 posed (2) the construction of a power dam 

 at Rocky Reach (now under construction) 

 on the Columbia River 9 miles north of the 

 City of Wenatchee. This P.U.D. operates 

 the Rock Island Dam power development on 

 the Columbia River 12 miles below Wenatchee. 

 The Chelan P.U.D. has applied for a license 

 from the Federal Power Commission to con- 

 struct a dam on the Wenatchee River in the 

 Tumwater Canyon area 35 river miles west of 

 Wenatchee. This dam would divert water 

 into a tunnel leading to a downstream 

 powerhouse to be located near the City of 

 Leavenworth. Studies for a power dam on 

 the Chiwawa River have been deferred be- 

 cause of the high cost for a single-purpose 



project on this river. 



The U. S. Corps of Engineers 308 

 Report of 1948 (_3) proposed a single high 

 dam at Priest Rapids on the Columbia River 

 68 miles downstream from Wenatchee. After 

 this power site was acquired by the Grant 

 County P.U.D. by action of Congress and 

 by license from the Federal Power Commis- 

 sion, the P.U.D. decided (4^) to erect two 

 run-of-river dams to develop the power 

 potential, rather than a single high dam. 

 Cost comparisons and other factors led to 

 the selection of this 2-dam scheme. The 

 Priest Rapids Dam is now under construe t ic:. 

 and it is anticipated (4_) that construction 

 on the Wanspum Dam will commerce during 1958. 



Table 1 (page 3) gives pertinent data 

 on these dams and the other dams, existing 

 or proposed, in the area included in this 

 study (see fig. 2 for location). These 

 dams are primarily for the production of 

 hydroelectric power. They will have some 

 multipurpose use however, in their naviga- 

 tion locks (when built) and in their (very 

 small) flood control storage that can be 

 made available by drawndown of the reservoir 

 in advance of expected flood storage use. 

 As shown in table 1, these are low head, 

 run-of-river dams. They provide, at mean 

 river flow, a theoretical water rentention 

 period (not for flood control) in the reser- 

 voirs of only 0.25 to 4 days —( With com- 

 pletion of the proposed dams on the Columbia 

 River, the river will be a series of lakes 

 from Bonneville well into Canada, a distance 

 of some 620 river miles. 



1/ Rock Island has the lowest detention 

 period of 0.25 days and Ice Harbor the 

 greatest, or 4 days. 



