water quality of the Wenatchee River, the 

 physical and chemical characteristics at the 

 sampling stations were plotted versus miles 

 downstream from Lake Wenatchee on figure 20. 

 In general it can be seen that there was a 

 downstream increase in jill physical and 

 chemical characteristics except carbon diox- 

 ide and ammonia. These slight increases 

 were expected, for as a rule a river picks 

 up increased amounts of suspended and dis- 

 solved constituents as it flows from its . 

 source toward the ocecin. The decrease in 

 carbon dioxide was probably due to photosyn- 

 thesis. The downstream decrease in ammonia 

 concentration was hardly significant, but 

 nonetheless was unexpected. Ammonia is one 

 of the results of decomposition of organic 

 matter, and due to the upstream discharge 

 of sewage it was anticipated that it would 

 increase in the lower river. A possible ex- 

 planation for this condition may have been 

 that sufficient time had elapsed since the 

 introduction of the organic matter for 

 nitrite producing bacteria to transform the 

 ammonia into nitrites. 



COMPARISON OF WATER QUALITY, 

 WENATCHEE RIVER AND COLUMBIA RIVER 



carbon dioxide was found in both streams. 

 These investigations revealed the two rivers 

 to be alkaline with the Wenatchee having an 

 average pH of 7.3 and the Columbia an aver- 

 age of 7.8. The hardness of the Columbia, 

 66 ppm, was about 2-1/2 times that of the 

 Wenatchee, 27 ppm. The alkalinity exhibited 

 about the same relationship, 60 ppm in the 

 Columbia and 28 ppm in the Wenatchee. 



THE EFFECT OF IMPOUNDMENT OF 

 WATER QUALITY 



Included as part of the purpose of this 

 study was the establishment of the water 

 quality characteristics of the Wenatchee and 

 Chiwawa Rivers prior to impoundment due to 

 hydroelectric projects, cind to make predic- 

 tions regarding the effects of the impound- 

 ments. 



Effect on Physical and Chemical 

 Water Quality 



The effect impoundment has on the 

 physical and chemical' water quality is sub- 

 ject to a number of VEiriables, some of 

 which are listed below: 



A comparison of the physical and chemi 

 cal characteristics of the Wenatchee River 

 at Sleepy Hollow determined in this study 

 and those found by Sylvester (1957) 

 for the Columbia River at Rock Island 

 is shown in table 22. 



1. The physical and chemical quality 

 characteristics of the water enter- 

 ing the in^joundment . 



Referring to table 22, it can be 

 seen that the waters of the two rivers 

 were similar in some respects and 

 different in others. The turbidity, 

 10 units in the Wenatchee and 6 units 

 in the Columbia, was low in both 

 rivers. The average color of 10 units 

 was the Scime for both rivers and was 

 considered to be low. The Columbia 

 had almost 2-1/2 times the ionized 

 mineral content of the Wenatchee, as 

 indicated by the specific conductiv- 

 ities of 131 and 56 micromhos per cis., 

 respectively. The dissolved oxygen 

 content was essentially the same in 

 both rivers, averaging 11.4 ppm in 

 the Wenatchee and 11.8 in the Colum- 

 bia. Both streams were found to be 

 supersaturated with dissolved oxygen, 

 with the Wenatchee averaging 103 per- 

 cent and the Columbia averaging 116 

 percent. An average of 1.0 ppm 



Table 22. — Wenatchee River at Sleepy Hollow and Columbia 

 River at Rock Island — Average water quality, 

 1954-1955-1956 i/. 



Temperature (° F.) 

 Turbidity (units) 

 Color (units) 

 Specific conductance 



(micromhos/cm at 25* 

 Dissolved oxygen (ppm) 

 Percent saturation D.O. 

 Carbon dioxide (ppm) 

 pH 



Total hardness (ppm) 

 Alkalinity (ppm) 

 Sulfates (ppm) 

 Ammonia (ppm) 

 Total solides (ppm) 



C.) 



1_/ Average values do not represent the true average 

 since the sampling frequency was not uniform. 



2/ Sylvester, 1957. 



30 



