on the Lewis River in 1931, fish in the 

 downstream salmon hatchery died. The death 

 of these fish was blamed on several differ- 

 ent factors, viz.; water quality changes 

 brought about by the release of impounded 

 waters with their decomposition products 

 from a reservoir site that was not cleared 

 of organic debris; by the leeching of alka- 

 li from the dam itself; by the leeching of 

 toxic materials frcxn the inundated reser- 

 voir area; by a rise in water temperatures; 

 or from Improper arrangements for hatchery 

 operation. 



A letter frcxn the California Depart- 

 ment of Fish and Game, December 31, 1956, 

 is quoted in part to illustrate their 

 experiences with new reservoirs on water 

 quality. 



"When Folscan Dam was completed last 

 year, we experienced a very severe problem 

 of oxygen depletion in the American River 

 below the dam. You may know that the 

 reservoir site was not cleared too care- 

 fully. The dam was completed in the spring 

 of 1955 hut ver^-- little water was stored 

 that year. By September of that year the 

 storage was down to less than 50,000 acre 

 feet. At that time there were about ten 

 days of extremely hot weather and the 

 reservoir became septic. Water releases 

 through the power house into the afterbay 

 dam contained no dissolved oxygen and up 

 to ten parts per million of dissolved svuL- 

 fides. 



"As a result the water in the after- 

 bay reservoir became septic and a consider- 

 able mortality resulted in the trout that 

 had been planted there a short time before. 



"The Department of Fish and Game 

 operates a salmon hatchery to replace the 

 spawning area cut off by the construction 

 of Folsom Dam, using water from the after- 

 bay as a source of supply. The detention 

 time in the afterbay reservoir is quite 

 short, and although the reservoir is about 

 six miles long there was insufficient sera- 

 tion to reoxygenate the water before it 

 reached the hatchery intake at the afterbay 

 dam. 



"As a result, we experienced a con- 

 siderable mortality of salmon in the 

 hatchery and it took the river about seven 

 miles to recover to a point above 5.0 parts 

 per million with a flow of over 500 c.f.s. 



"This condition persisted for about 

 two weeks until the weather became cooler 

 and there was some rain which produced seme 

 fresh water inflow into the reservoir. 



"This is the first time this has 

 happened in California and it caused us 

 considerable difficulty. The problem did 

 not occur this year because there was a 

 great deal more water stored in Folsom 

 Reservoir. 



"This pretty well convinced us of the 

 necessity of very good clearing of organic 

 material from large reservoir sites. Shasta 

 and Millerton reservoirs, which are similar 

 in appearance and size of Folsom, had no 

 oxygen depletion problem develop in either 

 instance. The reservoirs were completely 

 cleared. 



"The situation at Copco Dam is some- 

 what different. The Klamath carried a 

 rather considerable algae load and there is 

 a rather well-defined thermocline in Copco 

 Reservoir. I believe that the power house 

 intEikes are below the theimocline and as a 

 result the discharge is deficient in dis- 

 solved oxygen at times but the river re- 

 covers very rapidly and I don't think it is 

 having siny effect on the fisheries resources 

 of the stream." 



R. M. Paul 



Water Projects Coordinator 



Data were collected from the Yale and 

 Merwin Reservoirs on the Lewis River, the 

 Bonneville, McNary and Roosevelt Reservoirs 

 on the Columbia River and from Lake Wenat- 

 chee. These data are not included in this 

 report as they are brief and were obtained 

 for the purpose of interpreting downstream 

 water quality. Lake Wenatchee water quality 

 values win be included in a separate report 

 on the Wenatchee River Basin. 



Streams 



Table B in the appendix lists sampling 

 stations one through forty together with 

 the minimxmi, average and maximum constituent 

 values observed during the sampling period 

 of Jvine 195'^ through September of 1955- Sta- 

 tions 13, 1^, 16, 17, 22, 23, 37, 38 and ko 

 are for the period of June 1954 through 

 December 1956. Average values do not repre- 

 sent a true average for the period since 

 the sampling frequency was not unifonn. 



■>k 



