Our new Biological Assessment is out - Klamath Basin Crisis

Klamath Project Operations Biological Assessment
Introduction, Action Area, and Proposed Action: Detailed Proposed Action
Modeling Assumptions:
(1) Minimum IGD flows are as indicated in the Proposed Project.
(2) Minimum UKL elevations are as indicated in the Proposed Project.
(3) Priorities are river, lake, Project from April through September.
(4) Lake level refill targets are as indicated in the Proposed Project.
(5) Distribution of a portion of storable inflow to the river, October through
February, after monthly UKL refill targets are achieved.
(6) Distribution of a portion of the April-September surplus to the river in May –
September, varying the percentage of the surplus depending on the seasonal
supply, i.e., 35% in wetter years, 25% in median years, and 10% in drier
years. The actual percentage varied linearly with the water supply. The
distribution was: May 1-15 15%, May 16-31 15%, June 1-15 20%, June 16-
30 20%, July 1-15 7.5%, July 16-31 7.5% and September 10%. This
distribution was used in the modeling in an attempt simulate how the IM
process might be used to distribute available water.
It should be noted that WRIMS has the luxury of going back in time and using
actual historical UKL, LRDC and KSD inflows to adjust monthly distributions for
river flows and lake levels. Specific replication of these scenarios today would be
somewhat limited by the unpredictable future of the inflows listed above as well
as a number of other factors including; precipitation, snow pack and soil moisture
content, temperature, etc. Operations in the future would attempt to achieve
similar results using the IM process described in the BA.
The following exceedence tables reflect the estimated frequency that different
lake levels and river flows might be realized under the Proposed Action using
historical inflow data (Tables 1-5 and 1-6). For comparison purposes only,
Appendix 3-D contains similar tables illustrating modeled exceedence flows using
the NRCS April 1st forecast rather than the known historical inflows.
Note: Monthly exceedence flows will not always occur sequentially.
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