Biological Opinions - Bureau of Reclamation

lake management (USFWS 2008), and with loss of access to Lower Klamath Lake, rearing
habitat for the LRS and the SNS has been drastically reduced and degraded.
7.8 PacifiCorp’s Hydroelectric Project on the Klamath River from Keno Dam to Iron
Gate Dam
Lake habitats that support sucker populations were created in the Klamath River as a result of
construction of four dams (J.C. Boyle, Copco 1, Copco 2, and Iron Gate) that comprise the
PacifiCorp Klamath Hydroelectric Project. No lake habitat existed historically in the Klamath
River below the Keno Reef, located upstream of the Keno Dam. LRS and SNS populations
(mostly SNS) have expanded into these lake habitats, most likely from downstream drift of
larvae and juveniles from UKL (Desjardins and Markle 2000). Populations in the Klamath River
hydropower reservoirs are small compared to those in UKL, Gerber Reservoir, and Clear Lake
(USFWS 2002, 2007c). Factors affecting sucker populations in the Klamath River reservoirs are
discussed in detail in the FERC BiOp for the proposed relicensing of the Klamath Hydroelectric
Project (USFWS 2007c). The greatest threats to suckers in these reservoirs likely come from
adverse water quality and nonnative fishes.
7.9 Climate Change
7.9.1 Western United States
In the western United States, there is a strong link between climate and the availability of water
resources. Surface water volume and recharge to groundwater are based primarily on winter
precipitation and snowpack. Climate change effects caused by global warming began in the mid-
20th Century and are continuing (Barnett et al. 2008, Christensen et al. 2004). The effects of
climate change between 1950 and 2000 include water shortages and changes in the timing of
runoff. The principal factors being (1) a shift to more winter precipitation falling as rain instead
of snow in mountainous regions, (2) earlier snow melt as a result of warming winter
temperatures, and (3) associated increases in river flow in the spring and decreases in the
summer and fall (Barnett et al. 2008). Continuation of climate change is expected to
significantly affect water resources in the western United States by the mid-21 st century, and
evidence suggests that the Klamath Basin region’s climate is already changing (Hayes 2011).
Climate change is generally predicted to result in increased air and water temperatures, decreased
water quality, increased evapotranspiration rates, increased proportion of precipitation as rain
instead of snow, earlier and shorter runoff seasons, and increased variability in precipitation
patterns (Reclamation 2011). Several studies have shown declining snow-pack, earlier spring
snowmelt, and earlier stream runoff in the western United States over the past few decades
(Hamlet et al. 2005, Regonda et al. 2005, Stewart et al. 2005, Knowles et al. 2006). Winter
precipitation and snow-pack are strongly correlated with streamflow in the Pacific Northwest
(Leung and Wigmosta 2004).
Increasing temperature is the major driver of these observed trends, particularly at the moderate
elevations and relatively warm winter temperatures characteristic of the Pacific Northwest
(Hamlet et al. 2005, Stewart et al. 2005). Temperatures are projected to continue increasing by
approximately 0.36˚ F (0.2 ˚C) per decade globally for the next several decades (Meehl et al.
2007).
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