Biological Opinions - Bureau of Reclamation

observed in the lower Link River, upstream from the west side hydropower facility (Smith and
Tinniswood 2007). It is unclear how the proposed Project operations affect upstream passage of
suckers in the Link River; both high and low flows could restrict upstream passage, but
intermediate flows might improve passage (Mefford and Higgs 2006). The proposed Project
operations include ramping rates and minimum flows downstream from the Link River when
suckers are present to reduce stranding that should eliminate nearly all of the adverse effects
from ramping and low flows on affected individuals.
The proposed Project operations maintain a surface elevation in the Keno Reservoir of 4,086.5 ft
(1,245.6 m), except for several days during the spring when the surface elevation is drawn down
2 ft (0.6 m) to facilitate maintenance of irrigation facilities. Stable surface elevations in the Keno
Reservoir could inhibit development of additional wetland habitats and degrade the quality of
existing wetlands (USFWS 2007c). Although current maximum water levels in Keno Reservoir
are thought to be similar to those that occurred naturally because of a reef near Keno that
controlled water levels (Weddell 2000), minimum elevations could have been lower historically
due to lower flows from UKL in the summer and fall. The proposed action in Keno Reservoir is
not anticipated to affect the availability of deeper habitats used by older juvenile and adult
suckers.
Sampling in the Lost River Diversion Channel and near the Ady and North Canals indicates that
juvenile suckers are present in low numbers near both locations during the summer (Phillips et
al. 2011). Their presence near these diversions suggests that suckers could be entrained by the
Lost River Diversion Channel and other Project diversions in the Keno Reservoir, but the
number of suckers entrained at facilities downstream from Link River Dam is thought to
progressively decrease downstream because some die and others likely remain in each reservoir,
so fewer are dispersing downstream (USFWS 2007c), thus entrainment is expected to be
substantially lower in the Keno Reservoir diversions than at Link River Dam.
Downstream from Keno Dam, effects of the Project on LRS and SNS are likely small in
comparison to other effects because there are fewer suckers present in the reservoirs, so effects
are primarily limited to changes in water quality (USFWS 2007c). The Project could also affect
water quantity downstream, but this is likely minor because PacifiCorp regulates releases
through the dams for hydropower production and keeps the reservoirs full, except for daily
changes in reservoir elevations for hydroelectric generation.
In the Keno Reservoir the proposed action could have a variety of adverse effects to the LRS and
the SNS, including entrainment into Project facilities and adverse water quality. Below Keno
Dam, effects are likely limited to reduced water quality. What the effects of reduced water
quality are to the LRS and the SNS is unknown and are not likely to be substantial at a
population level because of the low numbers of suckers present in the reservoirs; however, any
loss of suckers is adverse given the declining status of both species in the UKL recovery unit.
8.3.3 Summary of Effects of the Proposed Action to the UKL Recovery Unit
The UKL Recovery Unit is essential for the survival and recovery of the LRS and the SNS
because the UKL Recovery Unit contains one of only two previously self-sustaining LRS
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