228 



DRAFT 



"Mainstem Columbia and Snake River dams had significant upstream 

 passage problems as well. Gibson et al., (1979), estimated a 20 percent 

 adult mortality rate associated with passage at John Day Dam, and 

 Weiss (1970) estimated 13 percent associated mortality at Bonneville 

 Dam and 12-25 percent at The Dalles Dam. Similar adult mortality 

 (loss) rates may apply at older fish passage facilities elsewhere in 

 Oregon.... "The design and engineering of passage facilities have evolved 

 as successes and failures brought more understanding about sensitive 

 interactions between biological and engineered systems ' (Rainey, 

 1991). " 



The report implies that the adult losses at Bonneville, the Dalles, and John Day dams 

 can be attributed to outdated fish ladder designs - this is not true. The high mortalities 

 at these dams during the 1960s and 1970s were due to high flow and forced spill prior 

 to Columbia River Treaty storage. The cited studies (Gibson et al. 1979 and Weiss 

 1970) showed that adult losses were highest during high spill years due to fallback and 

 delay. 



In this paragraph, both Gibson and Weiss are cited but are not included in the 

 References section. At the end of this paragraph, "Rainey, 1991" is quoted but is also 

 missing from the References section. 



The second paragraph of page 58 incorrectly describes the 1991 Fish Passage Center 

 (FPC) Annual Report (FPC 1991). The following statements were inaccurately 

 reported: 



"Loss of adult fish was higher than normal in 1990 based on individual 

 dam counts..." 



The Fish Passage Center report does not state that "higher than normal losses of adults" 

 occurred. Rather, FPC (1991) reported that "fallback of adults probably occurred at 

 some projects during periods of high spill", and that warmer than normal water 

 temperatures July through September "likely caused additional mortalities". The FPC 

 report states these results as probable occurrences, nQl mortalities that occurred or were 

 measured in 1990. 



"High spill levels (to benefit downstream passage of smolts) from May 

 through mid-June. . . * 



The high spill levels occurred because of overgeneration (exceedance of powerhouse 

 capacity) from high natural runoff, not because of flow augmentation to benefit fish. 



"Passage efficiency was very low in the Sruike complex of dams in 1990 

 compared to 1989 (FPC, 1991). " 



This statement is not supported by the reference to FPC (1991). The FPC report does 

 not state that passage efficiency was low in the Snake complex in 1990 compared, to 

 1989. 



A-22 



