Biological Opinions - Bureau of Reclamation

survival rates, we know that some of these larvae survive because juveniles are found in the
canal system when they are drained at the end of the irrigation season. Up to 1,500 age-0
juveniles are salvaged as at the end of the irrigation season and moved to permanent water bodies
such as UKL where they are more likely to survive (Kyger and Wilkens 2010a).
Because of the higher summer flows in the Link River that are needed to meet Project irrigation
and environmental needs, this likely results in greater entrainment of age-0 juveniles than would
occur if there was no storage and delivery of water to the Project. Although fewer age-0
juveniles are entrained by the Project than larvae, loss of age-0 juveniles is more critical because
of the lack of recruitment into the aging adult populations of the LRS and the SNS in UKL. The
significance of this effect to UKL populations of the LRS and the SNS is likely to be magnified
if the lack of recruitment into the adult population continues and the existing adult population
continues to age and decline.
Entrainment rates at the A canal and Link River Dam due to Project operations are substantial
although other factors are involved as discussed above. Nevertheless, we anticipate that adverse
effects of entrainment to the declining adult sucker populations in UKL as a result of Project
operations will be minimized through the proposed relocation of adult suckers to UKL from
Lake Ewauna and the proposed controlled-propagation program, both of which are discussed
below.
The modified proposed action, mentioned above Sections 4 and 8.3.1.1, will not result in
entrainment rates different from those analyzed above because the modified flows at the Link
River Dam are within the range considered in the above analysis.
8.3.2 Effects to LRS and SNS Populations in the Keno Reservoir and Below Keno
Dam
Small numbers of the LRS and the SNS (with SNS dominating) reside in the Keno Reservoir and
in the downstream hydropower reservoirs operated by PacifiCorp (Desjardins and Markle 2000,
PacifiCorp 2004, Korson et al. 2008, Kyger and Wilkens 2011a, Phillips et al. 2011). Poor
habitat conditions and nonnative fishes are thought to be responsible for the small numbers of
LRSs and SNSs present in these reservoirs (Desjardins and Markle 2000, Piaskowski 2003;
USFWS 2007c, 2008).
The proposed action has a variety of potential effects to the LRS and the SNS below the Link
River Dam. Entrainment in Project facilities is one concern because Reclamation diverts water
at the Lost River Diversion Channel, and North and Ady Canals. Also, there are approximately
50 smaller diversions, some of which are part of the Project; most of these lack appropriate
screens. One potential effect of the Project on suckers in the Keno Reservoir is the degraded
water quality, the result of nutrient-rich agricultural return flows entering the reservoir at the
Straits Drain and from the Lost River Diversion Channel in winter/spring (ODEQ 2010).
However, overall, the diversion of water from UKL through the Project results in a net reduction
of nutrients entering Keno Reservoir from UKL (ODEQ 2010).
No known sucker spawning habitat exists in the Klamath River between the mouth of the Link
River and Keno Dam (Buchanan et al. 2011). However, some sucker spawning activity has been
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