2022 Sacramento River Operations – Temperature Management Plan

So much is at stake in this water year 2022: water supplies, water quality, agricultural production, hydropower production, as well as the future of salmon, steelhead, sturgeon, smelt, and other native fishes of the Klamath and Sacramento-San Joaquin watersheds. Despite the lessons of the 1976-1977, 1987-1992, 2007-2009, and 2013-2015 droughts, the choices and tradeoffs are more difficult, and effects more significant and consequential to the fish, in 2022, the third year of the 2020-2022 drought. The State Water Resources Control Board is about to approve 2022 water operation plans for Central Valley Project (CVP) and the State Water Project (SWP). Among the most immediate effects of these plans will be the fate of iconic fisheries resources of the Sacramento and Klamath Rivers, in 2022 and beyond.

The two key elements of the plans are (1) the Sacramento River Temperature Management Plan (TMP) governing Shasta/Trinity operations, and (2) the Temporary Urgency Change Petition (TUCP) governing Delta operations. A 4/5/22 post covered some aspects of the TUCP on Delta operations, which serves to cut demands on federal and state reservoir storage in the Sacramento River watershed by lowering Delta outflow requirements. (See also CSPA and allied organizations’ protest and objection to the TUCP.)

This post covers the 2022 TMP, which focuses on Shasta/Trinity storage releases and management of Shasta Reservoir’s storage releases and cold-water pool in support of Sacramento River salmon. It starts with a review of both the hydrological and biological effects of Shasta and Trinity operations in 2021. Starting with 2021 creates context in two ways. First, it explains the severe depletion of CVP and SWP storage in 2021, which created the avoidable portion of the extreme storage conditions of 2022. Second, it describes the disastrous failure to protect fish in 2021, both as consequence of bad management and contributor to the dire conditions of fisheries in 2022.

2021 Sacramento River Operations

The predominant characteristic of 2021’s operations of Shasta Reservoir and the Sacramento River was excessive reservoir storage releases over the spring and summer for water deliveries. Within this constrained context, the dominant biological features in 2021 were management of the cold-water pool for salmon , along with associated “downstream” effects on the lower river and Bay-Delta. The 2021 Sacramento River operations plan led to significantly reduced production in brood year 2021 of all four runs of Sacramento salmon.

I have divided the 2021 story into five event periods (Figure 1), each with differing conditions and outcomes:

Period A: The early-April through early-June period was characterized by rapidly rising high releases (6000-9000 cfs) for water deliveries in late April and May. Reclamation claimed it saved 300 TAF of Shasta’s cold-water pool using power bypass of warm surface water for the high spring releases. In reality, the excessive delivery of irrigation water unnecessarily depleted total Shasta storage by nearly 500 TAF and depleted the cold-water pool by 200 TAF. Those storage losses also crippled any ability to subsequently sustain the cold-water pool through the summer.

The releases of unseasonably warmer water (56-60ºF) also (as planned) inhibited spawning in the late-April to early-June portion of the winter-run salmon spawning season (about half of the historical season). It also stressed winter-run and spring-run adults in their upper river pre-spawn holding areas. Recent scientific studies suggest that such stress (extended holding and warmer water) may have contributed to thiamine deficiencies in spawners that contributed to poor subsequent fry survival and smolt production. Rapidly rising flows and water temperatures may have also compromised late-fall-run salmon egg incubation that normally continues into April. Irrigation deliveries in the middle and upper river led to lower flows and high water temperatures in the lower river (Figures 2 and 3); this both reduced the survival of emigrating spring smolts of all four races of salmon, and hindered and stressed upstream migrating winter-run and spring-run adults.

Period B: The mid-June period of cold-water releases (53-55ºF) was designed to stimulate winter-run adult spawning. It also provided 8000 cfs irrigation releases that unnecessarily depleted total storage and the cold-water pool by 6-8 TAF per day for nearly two weeks (~100 TAF lost cold-water pool and total storage). It also resulted in salmon spawning at 8000 cfs, spawning habitat conditions that led to water surface elevations that increased by one-foot and then dropped by two-feet over the summer salmon egg incubation season. I have not assessed the role of flow on the amount of quality spawning habitat available or on the potential of redd dewatering/stranding, although such factors should also be considered in evaluating an operations plan. Irrigation deliveries in the middle and upper river led to lower flows and high water temperatures in the lower river (see Figures 2 and 3), hindering and stressing winter-run and spring-run adults that were late in migrating upstream.

Period C: The late-June to early-August period was the main winter-run egg incubation period under 2021 operations. Flow releases increased to accommodate irrigation demands. Irrigation diversions, in turn, reduced flows in the river further downstream, leading to high water temperatures (72-78ºF) that blocked early arriving fall-run adult immigrants. A rise of almost two feet in water level in early June from the increased flow likely caused some redd scouring in the upper river spawning reach below Keswick Dam.

Period D: The mid-August to mid-September period was characterized by falling storage releases, associated declining water levels, and warming water as the cold-water pool and access to it declined. Winter-run egg incubation continued through the period and likely suffered from stressful water temperatures and redd dewatering. Flows in the lower river increased, and water temperatures declined, becoming less stressful for upstream migrating adult fall-run.

Period E: The late-September through November period was characterized by continued warming of water temperatures due to lessening access to Shasta’s severely depleted cold-water pool, followed by natural fall cooling. Releases and water levels declined rapidly in the spawning reach. At the beginning of the period, warm water interrupted or delayed spring-run and fall-run spawning, while a water level drop of several feet led to redd dewatering and stranding. Winter-run fry were also subjected to potential stranding during the drop in water level. Spring-run and fall-run spawning was likely hindered or delayed into November due to high water temperatures and decreasing flows and associated water levels.

The 2022 Plan

The May 2 2022 Final TMP Is a radical change from the 2021 plan and actual operations. For the first time, Reclamation has prioritized protection of fish over irrigation deliveries to senior Sacramento River Settlement Contractors. The changes also reflect the much lower available storage in this third year of drought (Figure 4). Water release projections are much lower to sustain the cold-water pool and cool downstream temperatures through the summer (Tables 1 and 2).

April Operations and Effects

April operations closely followed the draft plan that Reclamation submitted to the State Water Board on April 6. April operations using middle TCD gates and small imports of Trinity River water maintained Keswick releases at 52-53ºC and 3250 cfs per the draft 2022 TMP. Such operation helped preserve Shasta storage and the volume of the deeper, cold-water pool (<50ºF). Valley-wide precipitation since mid-April increased flows in the middle and lower Sacramento River, stimulating juvenile salmon emigration and adult spring-run and winter-run salmon immigration. A small pulse flow from Keswick to the 30 miles of spawning and rearing habitat below Keswick Dam would have helped stimulate and benefit these salmon migrations, especially those from the upper 30-mile reach that saw little or no benefits from the April storms, but this did not occur.

The draft TMP (April 6) had the same proposed releases from Keswick Reservoir as the final TMP (May 2). However, the end-of-September storage in Shasta Reservoir predicted in the final TMP (1135 TAF) is over 100 TAF lower than was the prediction in the draft TMP (1250 TAF).

Proposed May Operations

The proposed May 4500 cfs release would come from Shasta Dam’s middle gates with access to warmer surface water in the lake, thus saving some of the cold-water pool. Such savings would require warmer releases that would delay spawning and stress holding adult winter-run and spring-run salmon.

For those winter-run who do spawn in May, egg survival could be compromised by the warmer water. With warming surface waters and warmer reservoir inflows in May, and more pre-spawn adult salmon arriving in the 10-mile spawning reach below Keswick Dam, a Keswick release temperature maintained at or below 51ºF would ensure the 10-mile spawning and holding reach is maintained near 53ºF. A colder release would require proportionately more cold water be released from deeper dam gates.

In reality, middle gate operation through early May (Figures 5 and 6) has sustained cooler-than-expected daily-average release temperatures at 51-52ºF. Hydropower peaking has accessed the warmer upper layers of the reservoir (Figures 7 and 8), saving some of the cold-water pool as planned. However, middle-gate operation under hydropower peaking, and gradual warming of reservoir surface waters, will result in increasing release temperatures per the plan later in May. A rapidly warming reservoir may necessitate use of lower gates or less hydropower peaking operations to maintain <54ºF through May per the plan. If spawning commences in early May due to cooler than planned dam releases, higher late May release temperatures would begin to compromise earlier-spawned egg survival. This should cause some re-evaluation of the plan.

Proposed June-September Operations

The proposed June-September 4500 cfs release (4000 cfs in September) from Shasta Dam will be from the lower TCD gates from the cold-water pool at ~50ºF (Table 2). Slightly higher Keswick Dam release water temperatures are predicted due to warming in Keswick Reservoir at ~4500 cfs through-flow. Water temperatures 5 miles downstream at Highway 44 will increase slightly more due to warm air temperatures.

The final temperature management strategy, based on recommendations received from the Sacramento River Temperature Task Group (SRTTG), is to target 58ºF at Highway 44 during the initial part of the season and then target 54.5ºF for 16 weeks around the estimated peak spawning date of Aug 2. This would result in targeting 54.5ºF from June 7 through September 27 or until the cold water is used up. Due to the limited available control in operating the middle gates (as described above), temperatures in June and July may be cooler than 54.5ºF. Reclamation will operate the TCD to target as close as possible to 54.5ºF to conserve cold water for maintaining target temperatures throughout the critical period.

Reclamation also received feedback from SRTTG members that an initial target of 58ºF would help to conserve cold water for later during the more critical portion of the temperature management season. The problem with this is that it will delay spawning, stressing yet-to-spawn adults and compromising survival of earlier-spawned embryos.

Fall Operations

Fall operations will be similar to those described above for Period E in 2021, with the exception of a lesser drop in flow. Water temperatures in late summer and fall will increase as the cold-water pool is depleted and access to it ends. Increasing temperatures will delay spring-run and fall-run spawning and stress pre-spawn adults (potentially aggravating the thiamine deficiency problem).


The planners have noted significant uncertainties that will require intensive real-time operations and management throughout the summer to achieve the various goals and targets throughout the system. To address uncertainty, Reclamation has employed conservative estimates of future conditions in the modeling assumptions (e.g., hydrology, operations, and meteorology) and projections, and has included as part of the TMP the potential to make changes, in consultation with the SRTTG, Water Operations Management Team, and/or the Shasta Planning Group. The State Board and NMFS should be included in the decision process.

Infrastructure limitations

The 2022 TMP was developed in consideration of the limitations on using the TCD and the need for temperatures below 56ºF at the Livingston Stone National Fish Hatchery. Efforts to address these limitations should be accelerated. Hydropower peaking operations changes should also be considered.

Related Actions to the Final 2022 TMP

1. Six-Fold Increase in Winter-Run Hatchery Smolt Production
Reclamation plans to fund a six-fold increase in the production of hatchery winter-run smolts this year with staged fall-winter releases from the hatchery and Battle Creek. Such releases should timed to coincide with natural flow pulses and pulse flows from Keswick Dam.

2. Transfers of Adult Salmon
The plan includes the capture and transport of adult winter-run salmon to the headwaters of Battle Creek. Good additional measures would be to give these adult fish thiamine injections and to enhance spawning gravels in Battle Creek as soon as possible.

3. Thiamine Treatments
Stresses imposed prior to spawning (e.g., delayed spawning, low flows, warm water during migration) and holding contributes to thiamine deficiency and high mortality of yolk sac fry, both in hatcheries and wild salmon1. Only hatchery salmon can be treated effectively at adult or egg stage, so efforts should be made to treat any wild adults that are handled, as well as to minimize pre-spawning stresses (e.g., erratic flows and high water temperatures).

4. Water delivery cut to 18% to Settlement Contractors
The TMP proposes to limit water deliveries to Sacramento River Settlement Contractors to 18% of their contracted amounts. The State Board should enforce this limitation. Reclamation should subordinate the timing of water releases to contractors to the needs of salmon downstream of Keswick Dam.

5. Reduced Downstream Deliveries
Demand on Shasta storage for Delta inflow/outflow has been reduced by relying more on other SWP/CVP and non-project reservoirs. However, lower Sacramento River and Delta inflows have reached water temperatures above 65ºF in early May, which puts additional stress on salmon that are immigrating in late spring. It is not a question of whether in May or June lower river water temperatures will exceed 68ºF – the state standard – but when.

6. System-Wide Water Management
Reclamation plans to manage system water supplies to minimize demands on Shasta’s cold-water supply. The Plan and temperature modeling relies on numerous drought actions throughout the Sacramento watershed to reduce reliance on stored water from CVP and SWP reservoirs this summer. “These drought actions have added a degree of flexibility to manage storage at Shasta, Oroville and Folsom reservoirs for meeting public health and safety needs, repelling salinity in the Delta, producing hydropower and providing additional cold water for fishery protection throughout the summer.” In 2022, Reclamation has finally cut deliveries to Sacramento River Settlement Contractors substantially below minimum amounts stated in contracts, in order to protect salmon. However, DWR has not done so for Feather River Settlement Contractors. Reclamation and DWR should be looking at system-wide delivery reductions. Reclamation should also call on New Melones for Delta salinity control as needed. See also NRDC et al. Objection to the TMP (May 6, 2022) for additional recommended system measures.

7. Real-Time Adjustments and Reporting
“Daily releases may vary from these flows to adjust for real-time operations. Significant uncertainties exist within the forecast that will require intensive real-time operations management throughout the summer to achieve the various goals and targets throughout the system.” Reporting, scrutiny, and decision making should be open processes.

8. Restoration of Salmon Upstream of Dams
Reclamation is committed to restoring endangered salmon to their historical habitat upstream of Central Valley rim dams. This program should be accelerated.

Tables 1 and 2 are copied directly from the Final TMP dated May 2, 2022.

Figure 1. Keswick Dam release water release rate and temperature, April-November 2021. Five general periods (A-E) are depicted, based on flow-temperature conditions as described in more detail in text. A. Spring high storage release rate (6-9K cfs), including extensive power bypass releases of warm surface water. B. A late-June cold water release to stimulate winter-run salmon spawning (<53ºF). C. A post-spawn higher irrigation release period with late-egg-stage sustaining water temperatures. D. Cold-water pool saving period with falling flows and higher water temperatures. E. Early fall period with loss of access to cold-water pool and reduction in storage releases.

Figure 2. April-December 2021 Sacramento River flow below Keswick Dam (river mile 300) and below Wilkins Slough (river mile 120). The difference between the two locations, plus tributary and ag return inputs, equals total irrigation deliveries via surface diversions and ground water depletions.

Figure 3. Water temperature in the lower Sacramento River at Wilkins Slough (river mile 120) May-August 2021, along with average for past 13 years. Note that the state’s year-round water quality standard for the lower Sacramento River is for water temperature to remain below 68ºF. Water temperatures above 65ºF are stressful to migrating juvenile and adult salmon. Water temperatures above 70ºF hinder adult salmon migration. Water temperatures above 75ºF are lethal to salmon.

Figure 4. Shasta Reservoir storage in 2022 and other selected years.

Figure 5. Shasta Reservoir water temperature profile at end of April 2022.

Figure 6. Water temperatures of Shasta and Keswick Dam releases in 2021 and to date in 2022.

Figure 7. Hourly water temperature in Shasta Dam releases, 4/27-5/7 2022.

Figure 8. Hourly Shasta Dam flow releases 4/27-5/7 2022.

  1. Adult salmon thiamine stores reduce most during the pre-spawning fast (Vuorinen et al. 2020).  Vuorinen PJ, Rokka M, Ritvanen T, Käkelä R, Nikonen S, Pakarinen T, Keinänen M. 2020. Changes in thiamine concentrations, fatty acid composition, and some other lipid-related biochemical indices in Baltic Sea Atlantic salmon (Salmo salar) during the spawning run and pre-spawning fasting. Helgol Mar Res. 74(1):1–24. doi:https://doi.org/10.1186/s10152-020-00542-9. (Crossref), (Web of Science ®), (Google Scholar) https://hmr.biomedcentral.com/articles/10.1186/s10152-020-00542-9

Lake Shasta – Late Fall 2021

When I first moved to California in fall 1977, I camped at Lakehead on Lake Shasta. I was surprised to only find the Sacramento River. I got the same view on a recent visit (Figures 1 and 2). No black bass or channel catfish, and few trout. The lake is down nearly 200 feet from when it last filled in spring 2019 (Figure 3). Storage is at 25% capacity (Figure 4). Flows were high from recent storms. The “river” was cutting into decades of deposited sediment, making what remained of the lake very turbid. Not the greatest conditions for my favorite fall fishery for spotted bass and trout.

Figure 1. Mid-November 2021 photo of Sacramento River arm of Lake Shasta. Note river cutting through historic lake sediments.

Figure 2. Mid-November 2021 photo of Sacramento River arm of Lake Shasta. Note “cuts” in lake sediment and turbid water.

Figure 3. Water surface elevation in Lake Shasta 2019-2021.

Figure 4. Current and historical water-year conditions for Lake Shasta storage.

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.



Shasta Dam Update – July 18, 2021

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

  1. 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.
  2. 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.

Figure 1. Shasta Reservoir inflow, outflow, and storage, 1-16 July, 2021.

Figure 2. Shasta Dam operations scheme and reservoir conditions during the first week of July 2021. Note middle remain open to accommodate peaking power releases and high downstream irrigation deliveries.

Figure 3a

Figure 3b Figure 3a and 3b. Hourly water temperature (a) and flow (b) release pattern from Shasta Dam during first half of July 2021. Note most peaking-power releases are in afternoon and evening hours, with water temperatures several degrees higher during the daily peak generation. Daily average releases were 6500-7500 cfs, with peaks on the 6th and 9th.

Figure 4a

Figure 4b Figures 4a and 4b. Hourly water temperature (a) and flow (b) release pattern from Whiskeytown Dam during first half of July 2021. Note most peaking-power releases are in afternoon and evening hours, with water temperatures in the middle range of the daily pattern or about 1ºF below the daily maximum. Note the base flow of 250 cfs is to Clear Creek, with the remainder to Spring Creek powerhouse on Keswick Reservoir. Also, note peak releases to the Spring Creek powerhouse were about 3500 cfs for 12 hours from July 3-8. Daily average releases rose from about 1000 cfs on July 1 to 2000 cfs on July 4, then dropped to 1500 cfs on July 11, only to increase again through July 15.



  1. As much as 50% of spawning may yet occur. See https://escholarship.org/uc/item/00c1r2mz 
  2. This is an update from my late June report on Shasta Dam operations.
  3. It takes about 1000 cfs of Shasta’s cold-water pool to cool 2000 cfs of 56-57ºF Whiskeytown water.
  4. https://www.fisheries.noaa.gov/feature-story/endangered-winter-run-chinook-salmon-increase-millions-offspring-headed-sea
  5. https://www.fisheries.noaa.gov/video/species-spotlight-sacramento-winter-run-chinook-salmon

State Water Board to Decide Fate of Shasta and Scott River Salmon and Steelhead – Part 3, the Shasta River

On July 1, 2021, staff from the State Water Resources Control Board (State Board) held a public Zoom meeting to provide information and solicit input on potential actions that could be implemented to address low flows in the Scott River and Shasta River watersheds (Figure 1) during the ongoing drought.  The Scott and Shasta rivers are major salmon and steelhead producing tributaries of the Klamath River. The State Board’s July 1 workshop sought input and options prior to taking action.   

CSPA is providing comments through this three-part series.  Part 1 was the introduction with a description of the general problems and solutions.  Part 2 provided specific comments on the Scott River.  This is Part 3 on the Shasta River.

The Shasta River Problem

The Shasta River, like the Scott River, has a chronic streamflow problem that occurs in summer and fall of most years.  Only in very wet years, do flows sustain the needs of ranchers and fish for water.  In most dry years, nearly all the water in the watershed goes to agriculture, while  the lower river and most major tributaries run virtually dry (Parks Creek, Little Shasta River, Yreka Creek).  Salmon and steelhead survive during dry years only in the middle reaches of the mainstem Shasta River and in adjoining large springs fed by Mt. Shasta’s snow fields or leakage from Lake Shastina reservoir.

At the locations in the watershed that are watered by springs, large portions of the spring-fed flow are diverted for agriculture or other human use (e.g., bottled water, domestic use, cities, etc.).  Pasture irrigation, hay production, and stock watering are the major uses.  Much of the upper mainstem’s  water supply (both spring-fed and snowmelt) is stored in Lake Shastina and metered out over the summer for downstream use through a large canal and ditch irrigation system.  Big Springs, the dominant source of spring water to the middle and lower river, is diverted or pumped to irrigation ditch systems from several small diversion dams and multiple small distribution systems.

Most salmon and steelhead spawning and rearing occurs in the middle reaches of the river below Lake Shastina and in the reach near Big Springs, where spring-fed cold-water provides high quality spawning and rearing habitat.  The inputs of spring water in summer of drier years like 2021 are virtually gone by the time river water reaches Yreka (Figure 2) from the above mentioned extraction systems.  The base flow of approximately 150 cfs before the April 1 start of the irrigation season falls to 10-20 cfs or lower by summer.  Flow recovers after the irrigation season ends on October 1.  Most of the irrigation diversions in the mainstem Shasta River are located in the 10-20 miles downstream of the inflow from Big Springs, as is evident by at the streamflow gage near Montague (Figure 3).

Lower flows lead to high water temperatures in the lower river (>65ºF, Figure 4) that limit fish habitat, survival, and smolt production. Unlike the Scott River, dewatering and stranding are not a primary factor in the middle river’s spring-fed refuge.  Rather, the problem is high water temperature between Grenada and the Shasta River’s mouth at the Klamath River.  Historical water temperature records at the Yreka gage (Figure 5) indicate that the lower river is virtually uninhabitable in summer with water temperatures 20-25ºC because of low streamflows.  Historical data from the Montague gage indicate tolerable water temperatures (<20ºC) when streamflows are >50 cfs (Figure 6).   Such flows and water temperatures would at least provide minimum requirements for migrating adult fall run Chinook salmon in late summer.

Solution Option for the Shasta River

CDFW’s recommended minimum instream flows of 50 cfs (about a third of the base flow) is a reasonable measure that would maintain a modicum of over-summer rearing habitat in the spring-fed middle reach of the Shasta River and provide the opportunity for the late-summer salmon migration.   The major objective is to protect the many spring inputs in middle reach of the river, where most over-summer rearing of salmon and steelhead occurs, through summer season.  This can be accomplished by cutting back diversions and groundwater pumping in the Big Springs area, and by minimizing warm, polluted irrigation return water.

Figure 1. The Scott River and Shasta River Valleys in northern California west of Yreka, CA (Yreka is located in the Shasta River Valley). The Scott and Shasta Rivers flow north into the Klamath River, which runs west to the ocean. The Salmon River watershed is immediately west of the Scott River watershed. The upper Trinity River watershed is immediately to the south of the Scott River watershed.

Figure 2. Shasta River daily-average streamflows at Yreka gage 2018-2021 and historical average. Note very low flows in April 1 to October 1 irrigation season in 2020 and 2021. Base flow from large springs is approximately 150 cfs. Lower flows are from surface and groundwater extraction.

Figure 3. Streamflow in Shasta River at Montague gage 2019-2021. Note distinct reductions in April 1 to October 1 permitted irrigation season.

Figure 4. Water temperature of Shasta River at Grenada 2019-2021. Note water temperature increase at beginning of irrigation season on April 1 and decrease at end near October 1.

Figure 5. Streamflow and water temperature (min-max) of Shasta River near Yreka CA, March-October 2003.

Figure 6. Streamflow and water temperature (min-max) of Shasta River near Montague CA, May-July 2008.