Our new Biological Assessment is out - Klamath Basin Crisis

Klamath Project Operations Biological Assessment
Coho Salmon: Environmental Baseline
Figure 3-9. Division 5, High Plateau of the Oregon Climatic Divisions, includes drainages
of the UKL.
in reviewing data from Division 5, High Plateau of the Oregon Climatic
Divisions, the Upper Klamath River Basin has been receiving less precipitation
since the early 1900s (Figure 3-10), while the mean annual temperature has been
getting warmer (Figure 3-11). While a long term trend of less precipitation and
warmer temperatures appears to be taking place, the year-to-year variation in
precipitation and temperature make it difficult to predict on a yearly basis. The
Klamath River has probably always been a relatively warm river (Hecht and
Kamman 1996 and p. 28, NMFS 2002 BO). In the Pacific Northwest, warm years
tend to be relatively dry with low summer stream flow and light snow pack.
Conversely, cool years tend to be relatively wet with high summer stream flow
and heavy snow pack (Scientific Consensus Statement [SCS] 2004).
Given these trends in climate, irrigation requirements, including those for the
Klamath Project, may increase into the future. In an already relatively warm
water system such as the Klamath River (Figure 3-12), less precipitation and
warming trends will also present long term challenges and are expected to place
additional stress on the coho salmon’s ability to survive and recover, as well as on
the water resources.
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