There is still time to take action needed to save some of this year’s salmon production in the Sacramento River.1 Reclamation must immediately stop its irresponsible operation and revert to a maximum 5000 cfs Shasta Dam release, with no release from the middle gates and with minimal peaking power releases or input from Whiskeytown Reservoir.2
Here is the situation right now:
- The last two weeks of July in the spawning reach near Redding will have daily average air temperatures over 85ºF, with highs of 100-107ºF.
- Shasta Reservoir is losing 10,000 acre-feet and ½ foot of water-surface elevation per day, due to excessive storage releases (Figure 1).
- Lower elevation dam release gates are about to go above the top of the cold water pool (Figure 2). This will reduce Reclamation’s ability to sustain cold-water releases through the summer for downstream salmon.
- Peak power releases draw warmer water from surface layers (Figure 3).
- Release of warmer 56-57ºF water from Whiskeytown Reservoir via Spring Creek Powerhouse into Keswick Reservoir further compromises Shasta’s cold-water pool3 (Figure 4)
- As Reclamation had predicted in its Temperature Management Plan, the bottom side gates will have to be opened to sustain cold water releases by mid-August, which will accelerate the loss of the cold-water pool and compromise cold-water dam releases.
- Diversions from the Trinity via Whiskeytown are getting warmer, requiring more of Shasta’s cold-water to overcome warming of Shasta/Keswick reservoir releases.
- Shasta’s warmer peaking power water also requires more cold-water pool water to maintain the target <54ºF Keswick Dam release temperature.
It is essential to maintaining cold-water releases from Shasta Dam into early October to save winter-run salmon reproduction in this critical drought year. Cold water ran out in the summers of 2014 and 2015, and the winter-run salmon runs plummeted.4 Recovery of this critically endangered species5 requires an all-out-effort to protect the survival of eggs and embryos over the summer in the 10-mile spawning reach below Shasta and Keswick dams.
Conclusions and Recommendations
- Releases from Whiskeytown Reservoir (Trinity River water) should be minimized, because the 2000 cfs of 56-57ºF water must be neutralized with water from the Shasta cold-water pool. It is taking about 1000 cfs of 48ºF water from Shasta to keep Keswick releases less than 54ºF. Eliminating the import of Trinity River water would save 2000 acre-feet of Shasta storage and cold-water pool volume each day. That would save over 100,000 acre-feet of Shasta storage and over 200,000 acre-feet of Trinity storage by the end of September.
- In addition to the cutting the Shasta release by 1000 cfs by discontinuing the need to offset warm Whiskeytown water, Shasta releases should be cut a further 1000 cfs by shutting off warm water from the middle gates (see Figure 2). This would further preserve the volume of the cold-water pool and save an additional 100,000 acre-feet of Shasta storage.
These actions would allow a 5000 cfs releases of <54ºF water from Keswick Dam through September, which would save a significant proportion of the endangered Winter-Run Chinook salmon. It would also save nearly 400,000 acre-feet of reservoir storage for water year 2022.
- As much as 50% of spawning may yet occur. See https://escholarship.org/uc/item/00c1r2mz ↩
- This is an update from my late June report on Shasta Dam operations. ↩
- It takes about 1000 cfs of Shasta’s cold-water pool to cool 2000 cfs of 56-57ºF Whiskeytown water. ↩
- https://www.fisheries.noaa.gov/feature-story/endangered-winter-run-chinook-salmon-increase-millions-offspring-headed-sea ↩
- https://www.fisheries.noaa.gov/video/species-spotlight-sacramento-winter-run-chinook-salmon ↩