Our new Biological Assessment is out - Klamath Basin Crisis

Klamath Project Operations Biological Assessment
Coho Salmon: Effects of the Proposed Action on Coho Salmon
Table 3-25. Summary of available juvenile and fry coho salmon habitat at proposed
minimum flows and at the modeled 50 percent exceedence levels for four reaches.
(Study Reach Summary Results)
Reach 1
R. Ranch
Coho
Salmon
Life
Stage
Juvenile
Coho Salmon Available Habitat
October through September
Proposed
Minimum
Flows
91% to 100%, or
down to (99%)
Modeled 50%
Exceedence
92% to 100%, or
down to (96%)
March through
June
Modeled 50%
Exceedence
Down to (98%), to
down to (96%)
Fry 80% to 88% 80% to 100% 89% to 100%
Juvenile 36% to 42% 37% to 43% 37% to 43%
Trees of
Heaven 2 Fry 89% to 94% 86% to 100%, or
down to (96%)
86% to 100%, or
down to (96%)
Brown Juvenile Down to (79%), Down to (78%), Down to (54%),
Bear 2 down to (57%) down to (41%) down to (41%)
Fry 35% to 36% 34% to 56% 34% to 56%
Seiad 2 Juvenile 45% to 46% 44% to 51% 44% to 51%
Fry 97% to 100% 97% to 100%, or 100%, down to
down to (93%) (93%)
1 The percentage in () in the available habitat range indicates flows above the maximum
available habitat flow. Once the flow is at the maximum available habitat levels, increase flows
would reduce the available fry habitat.
2
Reclamation applied the minimum and 50 percent exceedence model flows at IGD directly to
these reaches to determine coho salmon available habitat. This would assume minimum
tributary input. However, it is likely that flows would be much greater under these assumed
IGD flows at these reaches, particularly given tributary inputs. Thus, the flows considered to
determine the percent of available habitat should be considered minimums.
Spawning Habitat
Under the current (NMFS 2002 BO) and under the Proposed Action, the October
through February minimum flow requirements are the same. This minimum flow
regime, for this time period (1,300 cfs), for all NMFS year types, was based on
limited measurements and observations “that fall Chinook [salmon] spawning
habitat would be adequate in the IGD to Shasta River reach under this IGD
discharge” (p. 68, NMFS 2002). NMFS further assumed that main stem passage,
tributary access, and spawning habitat for coho salmon will also be adequate
under this IGD flow regime.
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