Welcome to the California Fisheries Blog

The California Sportfishing Protection Alliance is pleased to host the California Fisheries Blog. The focus will be on pelagic and anadromous fisheries. We will also cover environmental topics related to fisheries such as water supply, water quality, hatcheries, harvest, and habitats. Geographical coverage will be from the ocean to headwaters, including watersheds, streams, rivers, lakes, bays, ocean, and estuaries. Please note that posts on the blog represent the work and opinions of their authors, and do not necessarily reflect CSPA positions or policy.

Long-Term Downward Trends in the Klamath River

Over the past dozen-odd years, there have been significant negative trends in flow, water temperature, and lake levels in the upper Klamath River in California.  The trends likely reflect global warming, climate, and patterns in water supply use in the Klamath watershed.  The parameters contribute to declines in toxicity and fish populations, which are the subject for a future post.

Klamath Lake Storage

Klamath Lake elevation and storage over the past dozen years have been significantly below average in five years: 2010, 2014-15, and 2020-2021 (Figure 1).  Year 2021 is the worst year in terms of lake level.  Minimum lake levels occurred at the end of drought years 2009, 2012, and 2014.

Klamath Lake Releases (Outflow)

Klamath Lake outflow patterns indicate low levels of outflow in drought years, but also a general decline in winter minimums over the past dozen years (Figure 2).  The low outflow minimums may reflect efforts to recover lake storage in low-storage years (e.g., winter 2012-13).

Klamath Lake Outfall Water Quality

The water temperatures of Klamath Lake outflow have risen significantly over the past dozen years, especially in drought years (with 2021 being the warmest), but also in some wetter years like 2017 (Figure 3).  Dissolved oxygen and pH have trended downward over the years (Figure 4).  Dissolved oxygen and pH have generally fallen in the summer, possibly an indication of lower summer algae production in the lake.  Low late-summer and fall oxygen levels likely reflect high organic loads and lower algae production in the lake above.

Lower Klamath River Flows into California

There has been a general downward trend in Klamath River flow releases from the JC Boyle Dam and Iron Gate Dam into California (Figures 5-7).  Minimum flow periods reflect the minimum flow periods from Klamath Lake (see Figure 2).  The dominant features are lower flows in periods of drought generally and the unusually low 2020 and 2021 flows in particular.

California Tributary Inflows to Klamath River

California tributary inflows to the Klamath (Figures 8-10) reflect the dry-wet year patterns of the upper river.  Years 2020 and 2021 have had unusually low tributary flows, especially in the Scott River.


The water levels, river flows, and water quality in the Klamath River watershed  from 2008 through 2021 have declined overall, dominated by drought in 2008-2009, 2013-2015, 2018, and 2020-2021. Current conditions are the worst during this thirteen-year period.

Figure 1. Water levels in Klamath Lake 2008-2021.

Figure 2. Water releases from Klamath Lake 2008-2021.

Figure 3. Water temperature of water flows from Klamath Lake 2008-2021.

Figure 4. Water quality of water flows from Klamath Lake 2008-2021.

Figure 5. Klamath River stream flow near Keno, Oregon.

Figure 6. Streamflow to lower Klamath River below Iron Gate Dam 2008-2021.

Figure 7. Streamflow to lower Klamath River below Scott and Shasta Rivers near Seiad Valley, California 2008-2021.

Figure 8. Shasta River flows 2008-2021.

Figure 9. Scott River flows 2008-2021.

Figure 10. Salmon River flows 2008-2021.



Poor First Indicators of 2021 Winter-Run Salmon Fry Production

The first indicators of winter-run salmon spawning survival in the Sacramento River in 2021 indicate poor production, as expected.1 The drought and Reclamation’s operations in 2021 have provided production levels on par with 2014 and 2015, the last two critical drought years.

Red Bluff screw-trap collections since August 1, 2021 have been very low (Figure 1). The spawning delay in 2021 due to high spring water temperatures and low flows may be delaying downstream movement. However, outmigration patterns are similar to 2014 and 2015 (Figures 2 and 3). Even 2020, a dry year with poor production, had numbers five times higher than 2021 to date (Figure 4). Historical wet years with good production like 2006 had collection numbers ten times higher (Figure 5). There is a slim chance that the spawning delays and low flows of 2021 will provide screw-trap collection patterns similar to 2018, a dry year with a later collection peak (Figure 6).

Regardless of the low fry production, the young winter-run salmon must still make it 300 miles to the ocean this fall and winter, a phenomenal hurdle under the best of circumstances. Low fall flows will make the journey difficult. The class of 2021 will get no help from storage releases. Like almost every other user of California water in the beginning of water year 2022, outmigrating winter-run salmon are wholly dependent on future rain to provide the water they need.

Figure 1. Late summer 2021 catch of salmon fry at Red Bluff traps with water temperature, streamflow, and water turbidity.

Figure 2. The 2014 catch of salmon fry at Red Bluff traps with water temperature, streamflow, and water turbidity.

Figure 3. The 2015 catch of salmon fry at Red Bluff traps with water temperature, streamflow, and water turbidity.

Figure 4. The 2020 catch of salmon fry at Red Bluff traps with water temperature, streamflow, and water turbidity.

Figure 5. The 2006 catch of salmon fry at Red Bluff traps with water temperature, streamflow, and water turbidity.

Figure 6. The 2018 catch of salmon fry at Red Bluff traps with water temperature, streamflow, and water turbidity.

A Possible Chance to Save Some Sacramento River Salmon in 2021

The Problem

The 2021 target upper water temperature limit for salmon spawning and gravel-bed egg incubation below Shasta/Keswick dams on the Sacramento River near Redding was 55oF.  It is a little late for that now.  Since September 1, Keswick releases have been greater than 56.5ºF, and are now approaching 58ºF.  That’s too warm for the winter-run salmon who have finished spawning (Figures 1 and 2).

But what about the far larger run of fall-run salmon during their peak October spawning?  Can water temperatures downstream of Keswick be lowered back to 55oF in October?  The answer is a qualified yes.

Figure 1. Daily average water temperature of Sacramento River near Redding (SAC gage), September 1-21, 2021.

Figure 2. Daily average water temperatures from Shasta Dam powerhouse (TCD), immediately below Shasta Dam (SHD), and from Keswick Dam (KWK) to Sacramento River, September 1-21, 2021.

The Solution

A “qualified yes” means it would be a complex undertaking involving two actions possible under Reclamation’s operation of its Shasta/Trinity Division:

  1. Switching most or all of Shasta releases to the cold-water lower river outlets of the dam and ceasing warm-water hydropower releases from the dam’s powerhouse.
  2. Minimizing warm-water hydropower releases from Whiskeytown Lake to Keswick Reservoir.

Much of the remaining cold-water pool in Shasta Reservoir is being used to overcome warm-water hydropower releases into Keswick Reservoir (~60oF or higher) before water is released to the Sacramento River below Keswick Dam.  Cutting hydropower releases and rationing the available cold-water-pool supply through Shasta Dam’s lower river outlets is therefore a potential solution to warm water releases to the river.  Though this would reduce hydropower in the short-term, it would save storage in the long-term.

The solution would require a substantial reduction in Shasta Reservoir releases to ensure the cold-water-pool is not exhausted over the next month or more.  However, reducing releases would lower river water levels and strand salmon redds or reduce egg-embryo survival of remaining active winter-run redds or any newly spawned spring-run and fall-run redds.

A possible resolution is to drop flows after the vast majority of winter-run fry have left their redds and before most of the fall-run salmon have spawned.  This has been the standard management approach in many years to save storage – sometime in late September or in October.

Further Context

Under present conditions in late September 2021, access to the cold-water pool in Shasta Reservoir occurs primarily during the afternoon/evening, during peaking-power releases (Figures 3-5) from the penstocks via the Temperature Control Device (TCD) on the face of the dam.  Side-gate openings on the TCD (Figure 6) are able to pull cold water from below only during peak releases.  This pattern indicates that a modified solution might be to reduce warm-water power releases during non-peak operations, while retaining some peaking power releases from Shasta Dam in combination with lower level dam outlet releases.

Figure 3. Hourly flow releases from Shasta Dam September 18-23, 2021.

Figure 4. Hourly water temperature of water releases from Shasta Dam September18-23, 2021.

Figure 5. Hourly water temperature of water releases from a Shasta Dam penstock September18-23, 2021.

Figure 6. Shasta Dam conditions and operation on September 15, 2021.


Addendum to the State Drought Plan – August 31, 2021, Part 3: Reclamation’s Bad Plan Left Fish Agencies with September Hobson’s Choice

Earlier this summer, the Bureau of Reclamation’s operations of Shasta Reservoir, under its Drought Plan jointly developed with the California Department of Water Resources (DWR), caused high water temperatures that delayed spawning of winter-run Chinook salmon to early summer (mid-June through mid-July).1 Winter-run salmon leave the redds after 2-3 months, which in 2021 will mean a mid-August through September peak emergence.

In their Addendum to the State Water Project and Central Valley Project Drought Contingency Plan issued August 31, 2021, Reclamation and DWR state how an increase in September releases responded to a request from fisheries agencies:

In the July Drought Plan update, Reclamation’s forecast for releases to the Sacramento River were 7,850 cfs in August, ramping down to a monthly average of 5,200 cfs in September, and then going back up to 7,550 cfs in October to move the transfer water referenced above. In late August, the fishery agencies reviewed updated data indicating that a flow of approximately 6,800 cfs was needed through early-October to protect several remaining winter-run Chinook salmon redds. As a result, Reclamation modified its previous plan and held releases at 6,800 starting August 26.

Not so fast. In 2021, as in 2014, Reclamation cast the die early in the year, releasing too much water that was too warm until late June (Figures 1 and 2). That was Reclamation’s call, not the choice of the fish agencies. The agencies know that in drought year 2014, Reclamation also maintained both high flow releases and high water temperatures early in the summer, and that therefore the winter-run salmon spawned late. The agencies also know that a drop the water level 2-3 feet at the beginning of September 2014 (Figures 1 and 2) proved catastrophic to eggs and alevin still in the redds. Such drops in water level, with most redds in 1-3 ft of water, cause dewatering, reduced inter-redd water flow, sedimentation within the redd, lower dissolved oxygen, higher redd water temperatures, early hatching, direct egg/embryo mortality, and restricted fry movement within and emergence from redds.

The planned drop in early September of 2-3 feet in water level, part of the original 2021 Drought Plan, was a bad part of bad plan from the get-go. In 2015, Reclamation at least tried to avoid the drop by keeping releases lower throughout the summer (Figures 1 and 2). The August Addendum insinuates that added loss of storage in September-October to maintain higher flow/stage was the result of fishery agency review, when the agencies never wanted nor originally approved the September drop in river flow. The steady flow/stages in 2015 (Figures 1 and 2) was the appropriate prescription.

Just as it was a happy circumstance for the Sacramento River Settlement Contractors that Reclamation delivered them too much water north of the Delta early in the year, it was a happy circumstance for Reclamation and the Settlement Contractors that their planned water transfers of about 200 thousand acre-feet (TAF) to buyers south of the Delta just happened to be ready to go just as the drop planned earlier in the summer was scheduled to happen. Transfer water in a market where prices are north of $1000/AF is the mother’s milk of the change in September Shasta operations (Figure 3).

The accelerated schedule of transfers from Shasta storage also reduces the opportunity for the State Water Board or its Executive Director to wake up and smell the receding predictions for the reservoir’s receding shoreline. The tables at the end of the August Addendum now predict end-of-November storage in Shasta to be an unprecedented 729 TAF, down from the July Addendum’s prediction of 849 TAF. The only numbers that have maintained relative consistency throughout the summer 2021 Sacramento River debacle are the levels of deliveries and transfers. That consistency has been matched and enabled by the silence of the Water Board.

In summary, the original 2021 Drought Plan did not address the real risk of redd stranding that proved devastating for the winter-run salmon spawn in summer 2014. The July-August 2021 stage drop was bad enough and should have been avoided, given that high water temperatures delayed the spawn of winter-run to late June. The fish agencies were cornered into choosing between a large September 1 stage drop in a bad original plan and the buy-now-but-pay-later option of maintaining higher flows through September. The additional drain on Shasta storage and Reclamation’s increasing inability to maintain cold water releases through October show the folly and poor design of the original Drought Plan.

This post is part 3 in a series on DWR and Reclamation’s August Addendum to the 2021 Drought Plan.

Figure 1. River stage below Keswick Dam June-October 2014, 2015, and 2021.

Figure 2. River stage at Bend Bridge, 60 miles below Keswick Dam June-October 2014, 2015, and 2021.

Figure 3: Reclamation’s Delta Exports August 15-September 15, 2021.

Addendum to the State Drought Plan – August 31, 2021, Part 2: This Is a Test(?)

The California Department of Water Resources (DWR) and the U.S. Bureau of Reclamation (Reclamation) released a Central Valley Drought Contingency Plan Update on August 31, 2021. Part of the Addendum’s section on Sacramento River Temperature Management describes bypassing Shasta Dam’s hydropower generating facilities in order to cool Shasta Reservoir releases to the lower Sacramento River:

Reclamation performed a cold water power bypass test on August 29 to determine the feasibility of using the bypass to cool Sacramento River temperatures in the late summer and early fall. The results of this test and any potential future partial bypass will be discussed with the fishery agencies through the Sacramento River Temperature Task Group to determine the potential benefits and impacts of taking the action and ultimately whether the group recommends a partial power bypass for consideration.

The Test

As summarized in the quote above, Reclamation conducted a test on August 29. The test involved releasing cold water from near the bottom of the dam rather than from the power penstock through the Temperature Control Device (TCD) tower on the inside face of the dam. Water temperatures of releases from the TCD steadily increased through late August as the water level in the reservoir continued to fall (Figure 1). Side gate intakes on the TCD were taking in increasing amounts of warmer water from near the surface each day (Figure 2).


The August 29 morning test involved releasing cold water from the bottom of Shasta Reservoir (with minimum TCD release). As expected, it dramatically reduced water temperatures (about 4º F), at the head of Keswick Reservoir immediately downstream of Shasta Dam, while the test was going on (Figure 3). The test was followed by the normal afternoon peaking-power, warmer releases from the TCD, penstocks, and turbines/powerhouse (Figure 4). It was difficult to determine the proportion of releases from the two sources (the blend) in the morning, but it was obvious that water released during the morning of August 29 was cooler than water released at other times during that day or other days that week. The effect of the August 29 test on the Sacramento River below Keswick Dam was barely noticeable (Figure 5).


Releasing cold water from Shasta Dam’s bottom outlet reduces river water temperature below Shasta Dam compared to release through the TCD. However, the Addendum leaves options for a “potential future partial bypass” of Shasta Dam’s power facilities a complete black box.

The prospective objective of a partial power bypass would be to cool the Sacramento River downstream of Keswick Dam, where the salmon are. So many more factors affect release temperatures from Keswick. The release from Shasta of 1000 acre-feet of water over a six-hour period, in a day when the total Shasta release was close to 14,000 acre-feet, offers little insight into a two or three-month strategy for managing the already-diminished cold-water pool that remains in Shasta Reservoir following a spring and summer of excessive releases by Reclamation.

Setting aside the element of time for a moment, Keswick release temperatures depend on the ratio of the colder water released from Shasta Dam to the warmer power releases from both Shasta Dam and Whiskeytown Dam (through the Spring Creek Powerhouse) to Keswick Reservoir. An immediate measure Reclamation can take to reduce the temperature of the Keswick release is to cease the 1000+ cfs it is releasing to Keswick from Whiskeytown.1 In the short term, this could bring the Keswick release close or closer to the 55º target maximum for the 10-mile reach downstream of Keswick.

Increasing the proportion of releases from Shasta’s bottom outlet would reduce water temperatures in the short-term. However, how long this benefit would last, and whether there would be a net improvement or the opposite over one month or two months, involves calculus of how much cold water the change in operations would drain from the cold-water pool, and how quickly. In this regard, the description in the August Addendum says nothing at all about “the action” or potential actions that “will be discussed” by the Sacramento River Temperature Task Group.

Reclamation has put itself in a position where deciding which fish to save is inseparably deciding which fish to sacrifice. Those may be the same fish: the fish saved now by decreasing water temperatures to protect eggs in the redds may die later when Reclamation runs out of accessible cold water to keep the alevin from those eggs alive in a month. About this, the breezy report of a test says nothing at all.

Then there is the unknown but potentially even more severe consequence of depleting Shasta storage this year in the face of looming disaster if water year 2022 is dry.

This post is part 2 in a series on DWR and Reclamation’s August Addendum to the 2021 Drought Plan.

Figure 1. Water temperature of Shasta powerhouse releases in August 2021.

Figure 2. Shasta Reservoir water temperature profile and TCD intake operation configuration at end of August 2021.

Figure 3. Water temperature of Shasta Dam releases 8/27-9/4 2021. Note August 29 morning power bypass test.

Figure 4. Flow from Shasta Dam August 27 – September 4, 2021.

Figure 5. Comparison of daily average water temperatures of Shasta and Keswick Dam releases in August 2021. Most of the difference is caused by warm water releases from Whiskeytown Reservoir (Trinity water) via Spring Creek power to Keswick Reservoir. Note the apparent small effect of August 29 power-bypass test on both river and TCD water temperature: water temperature leveled off rather continuing upward trend over previous 12 days.

  1. Spring Creek Powerhouse temperature had steadily increased to 57º by July 15, when the CDEC gage stopped reporting data.  The August Addendum says that Reclamation plans to reduce by half the Spring Creek Powerhouses releases it predicted in it July Drought update; Reclamation should finish the job and shut it down completely until the water is sufficiently cool.