By now you have probably heard that Klamath salmon are again threatened by warm water and ICH disease. You may also know that Sacramento River winter run salmon are again threatened with warm water below Shasta at Redding. You may not know that both are related, caused by the US Bureau of Reclamation’s operation of the Central Valley Project (CVP) and in particular Shasta and Trinity reservoirs.
Low flows in the lower Klamath are resulting in warm water and disease, shaping up as having the potential to repeat the massive 2002 die-off of salmon. Water temperatures in the lower Klamath and Trinity near 80°F are killing salmon and blocking their migrations.
Below Shasta on the Sacramento River near Redding, Winter Run Chinook salmon eggs are dying because excessively warm water is being released from Keswick Reservoir near Redding. Water temperatures near or above 60°F occur from Redding down to Red Bluff, the traditional spawning reach of Winter Run Chinook in summer. Egg mortality increases above 56°F.
Here is how the two events are related. The map below shows how the Shasta andTrinity projects are connected as part of the CVP. Trinity Reservoir is presently releasing about 2000 cfs, of which a little less than 500 cfs (52-59°F) is released down the Trinity into the lower Klamath where total flow is 2200 cfs and water temperatures approach 80°F. The other 1500 cfs from Trinity Reservoir is going to Keswick Reservoir via Whiskeytown Reservoir. This 59°F water from Whiskeytown mixes with 5500 cfs of 52°F water released from the Shasta cold-water pool to provide a release of 7000 cfs of 54-56°F water into the Sacramento River from Keswick Dam above Redding. Water temperatures in the Redding spawning reach are 56-60°F.
So the flows diverted from the Trinity are not only contributing to low flows and warm water in lower Klamath, they are also contributing to the water in the Sacramento at Redding that is too warm for salmon eggs. The need to cool Trinity water before it is released into the Sacramento below Keswick is also contributing to the depletion of the limited cold water pool in Shasta reservoir.
Klamath River tribes are asking for more water down the Trinity. Reclamation is offering a small pulse when salmon start to die. A better solution would be to equally split the Trinity release, providing an immediate benefit to the Klamath-Trinity salmon and also saving some of the cold water pool in Shasta. This would require the State Board to reduce deliveries to Sacramento Valley farmers by an additional 500 cfs.