Category Archives: Chinook Salmon

Reclamation Begins Summer Shasta Operations that Sacrifice Endangered Winter-Run Chinook Salmon to Power Production and Irrigation Deliveries

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Reclamation has begun its planned summer operation for winter-run salmon in this critically-dry summer of 2021. After delivering a lot of warm surface water from Shasta Reservoir to its downstream contractors this spring,1 Reclamation has now begun dipping into Shasta’s cold-water pool (Figures 1 and 2). Reclamation’s summer operation will encourage the holding salmon to spawn and, for a time, ensure the eggs can survive in the primary ten-mile spawning reach downstream to the mouth of Clear Creek (CCR). Reclamation’s plan would subsequently raise water temperatures later in summer, after peak spawning and embryo development have occurred.

In first five days (June 17-22) of the new operation, Reclamation met its target temperature. It has released about 8000 cfs of 53ºF water from Keswick Dam to the Sacramento River near Redding (Figure 3). It achieved the target by blending hydropower-peaking flows from Shasta and Whiskeytown dams in Keswick Reservoir, and then releasing the blended water to the Sacramento River below Keswick Dam. During this time, Reclamation released an average of 6500 cfs from Shasta Dam at 50-51ºF, and an average of 1200 cfs at 53ºF through the Spring Creek Powerhouse (SPP) from Whiskeytown, into Keswick Reservoir.

This operation is not sustainable over the summer. It uses more of the cold-water-pool volume than is necessary to maintain temperature control. It sacrifices the cold-water pool in order to continue power peaking and to maintain relatively high downstream irrigation deliveries. Considering all of the factors pushing Keswick release temperatures higher over the summer, there will not be enough cold water by the end of the summer to protect salmon.

High Shasta Dam releases in the afternoon and evening to meet peak power demands pull more water from the warmer surface waters of the reservoir (Figures 4-6). This then requires blending with cold-water releases to keep Keswick water cooler. A similar situation occurs with the Whiskeytown releases (Figure 7-8). In addition, water in Whiskeytown becomes progressively warmer over the summer and requires an ever-increasing amount of Shasta’s cold-water pool to cool that water. Atmospheric heating combines with heating of water from Shasta during power-peaking operations to further affect Keswick Reservoir’s water temperatures (Figures 9 and 10).

Reclamation’s current high demands on Shasta’s cold-water pool will thus require reverting in late summer to warmer water releases. This will lower the survival of late summer spawners and their eggs. It will also leave little cold water for fall-run salmon in October and November. Reclamation is willing to accept these trade-offs to make relatively high power and irrigation deliveries.

To reduce the loss of winter-run (and fall-run) salmon this summer, CSPA and two other organizations submitted an alternative Temperature Management Plan (CSPA TMP) to the State Water Board on May 23, 2021. The CSPA TMP would provide better summer water temperatures and salmon egg survival. The CSPA TMP, comprised of a transmittal letter, descriptive elements and spreadsheet, proposes a release of just 5000 cfs of 52-53ºF water from Shasta Dam’s gates and minimal warmer water inputs from Whiskeytown/Trinity. The CSPA TMP proposes a 5000 cfs release of 53-54ºF water from Keswick, with less daily peaking power production to limit withdrawals of warm water from the surface of Shasta reservoir.

The CSPA TMP would minimize impacts to the salmon and save approximately 200,000 acre-feet of Shasta storage. It would also save 200,000 acre-feet of Trinity storage. It would greatly reduce power production from five system powerhouses, though power generation capacity would still be available for periods of extreme power demand.

Above all, the CSPA TMP would reduce water supply deliveries in the Sacramento Valley and eliminate water transfers from Shasta in the summer and fall. Reclamation is willing to sacrifice a substantial portion of the Sacramento River’s salmon in order to prioritize agricultural water deliveries. The CSPA TMP prioritizes a system operation that will reasonably protect salmon, and allocates water supply based on the water that is available within the constraints of that operation.

Figure 1. Shasta Dam infrastructure and operations, and cold-water pool conditions, during the June 17-22 period. Note water release from PRG gates, drawing from the layer of water less than 48ºF, and release from middle gates of water that is 70ºF or warmer. The combined flow release from the Temperature Control Device was 6000-7000 cfs of 51-52ºF water.

Figure 2. Water temperatures (ºF) recorded at Sacramento River gages from Shasta Dam (SHD, RM 310) downstream to Red Bluff (RDB, RM 240) 5/1-6/16, 2021. Keswick Dam (KWK, RM 300) is the release point from the Shasta Dam complex to the Sacramento River. Spawning area is ten miles downstream of Keswick to mouth of Clear Creek (CCR). Red arrow points out yellow highlight of recently changed operation to benefit salmon spawning.

Figure 3. Water temperatures (daily average. ºF) from Shasta Dam release (SHD) and from Keswick Dam (KWK, RM 300) downstream through primary winter-run spawning reach to gage located just upstream from mouth of Clear Clear Creek (CCR, RM 290). Note: the difference between SHD and KWK release temperatures are due to inputs to Keswick Reservoir from Whiskeytown from Whiskeytown Reservoir through the Spring Creek Powerhouse (SPP) and to internal heating and mixing in Keswick Reservoir. The compliance control point gage is SAC, located at the midpoint of the ten-mile spawning reach. The compliance point target was 55ºF during the period.

Figure 4. Water temperature (ºF) at gage SHD immediately downstream of Shasta Dam, June 17-22.

Figure 5. Shasta Reservoir hourly outflow (cfs), June 17-22.

Figure 6. Water temperature (ºF) at gage SHD immediately downstream of Shasta Dam, June 17-22.

Figure 7. Hourly measued water release (cfs) from Whiskeytown.

Figure 8. Water temperature (ºF) at gage SPP immediately downstream of Spring Creek Powerhouse June17-22.

Figure 9. Keswick Reservoir hourly outflow (cfs), June17-22.

Figure 10. Water temperature (ºF) at gage KWK immediately downstream of Keswick Dam, June17-22.

Peaking Power at Shasta Dam in Summer 2021 – Saving Winter Run Chinook Salmon

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In a recent 6/13/21 post, I discussed various tradeoffs of Shasta Reservoir operations on water supply deliveries, power production, and salmon survival for summer 2021. In that post I made reference to tradeoffs with peaking power production at the Shasta hydropower system. This post provides more information on those potential tradeoffs.

Peaking Power Production

Peaking power refers to the release of varying amounts of water through power turbines on a within-day schedule to meet the peak power demands of the regional electric grid. Inflows into Keswick Reservoir near Redding show the peaking power production schedule from Shasta Dam and Whiskeytown Dam into Keswick Reservoir on the Sacramento River (Figure 1). Over a recent two-day period, June 12-14 2021, hourly inflows to Keswick Reservoir ranged from 1900 cubic feet per second (cfs) to 17,500 cfs. Peak inflows were in late afternoon and evening, reflecting peak power demands. Minimum inflows were in the early morning, when power demand is low.

Peaking Power and Water Temperature from Shasta Dam

High releases for peaking power at Shasta Dam can draw warm water from near the surface of Shasta Reservoir (Figure 2). Water temperature below the dam increased from 50ºF to 56ºF in the recent example peaking periods, June 12-14. The positive relationship between dam release flow and water temperature is obvious (Figure 3).1

Peaking Power and Water Temperature from Whiskeytown Dam

In contrast to Shasta Dam, there was minimal influence on water temperatures when there were peaking releases from Whiskeytown Dam from June 12-14. The release water temperatures into Keswick Reservoir through the Spring Creek Powerhouse are minimally influenced by the flow rate (Figures 4 and 5). On June 13, there was no peaking through Spring Creek Powerhouse, but there was little variation in water temperature from peaking days on June 12 and 14.

Summary of Shasta-Keswick Operations

Shasta-Keswick operations is about to enter a new phase of summer operations. Under the Bureau pf Reclamation’s planned operations, there will be larger volumes of exports from the Trinity River system through Whiskeytown Reservoir over the summer. There will also be larger release volumes from Keswick Reservoir to meet increasing downstream contractor demands (Figure 6).

Proposed Operations

The proposed CSPA Temperature Management Plan2 for June-October, 2021 would provide a lower Keswick Dam release. First, Trinity exports would end, except for releases of 300 cfs down Clear Creek, because Trinity water releases through Spring Creek Powerhouse are already pushing the threshold temperature of 53ºF. Second, Shasta release would be limited to releases from coldwater pool at 52ºF to provide 5000 cfs total Keswick release, thereby saving Shasta storage. Third, peaking power at Shasta Dam would be minimized to ensure that warm surface waters are not drawn into the TCD gates (Figure 7) during peaking operations.

Sustaining the cold-water pool in Shasta through the summer is a function of (1) maintaining total storage and cold-water-pool volume in storage: (2) reducing Whiskeytown releases when they become too warm (>53ºF); and (3) minimizing warm water from peak power releases. Such a strategy would help save winter-run salmon eggs in the summer spawning season.

Figure 1. Inflow (cfs) to Keswick Reservoir from Shasta Dam and Spring Creek Powerhouse (cfs), June 12-14, 2021.

Figure 2. Water temperature (ºF) of the water released from Shasta Dam, June 12-14, 2021.

Figure 3. Relationship between water temperature and Shasta Dam release volume, June 12-14, 2021.

Figure 4. Total reservoir release (cfs) from Whiskeytown Dam, June 12-14, 2021. Note that of the minimum 250 cfs release, about 125 cfs were released to Clear Creek to maintain base flows and were not releases through Spring Creek Powerhouse.

Figure 5. Water temperature of water exiting the Spring Creek Powerhouse into Keswick Reservoir, June 9-14, 2021.

Figure 6. Summary of Shasta operations, June 1-13, 2021. Note SAC is gage station 5 miles below Keswick Dam on Sacramento River. Source: https://www.usbr.gov/mp/cvo/vungvari/sactemprpt.pdf

Figure 7. Shasta Dam operations and reservoir storage conditions on June 10, 2021. Source: https://www.usbr.gov/mp/cvo/vungvari/sactemprpt.pdf .

  1. At other times, depending on specific conditions and operations, the opposite relationship is true.  See https://calsport.org/fisheriesblog/?p=3596, Figure 6, for example from 2014 when higher temperatures were associated with lower release volumes. ↩
  2. Referenced in https://calsport.org/fisheriesblog/?p=3714.  The May 23, 2021 CSPA Temperature Management Plan proposed limiting Trinity exports to 300 cfs for the entirety of the June-October period, to be released exclusively down Clear Creek.  In addition to the water temperature benefits in the Sacramento River, such operation would also conserve cold water and overall storage in Trinity Reservoir. ↩

The Week the Salmon Died

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It was the first week in June 2021. The salmon were the last of 2021’s endangered winter-run and threatened spring-run Chinook salmon heading up the Sacramento River to spawn below Shasta Dam and in tributary streams. Many were in the middle of their 300-plus-mile journey from the Golden Gate through the Bay, the Delta, the lower Sacramento River. Water temperatures rose to lethal levels through the lower end of the Sacramento River, as flows at Wilkins Slough (River Mile 125) dropped nearly 50% to 3500 cfs and water temperatures reached 25ºC (Figure 1).

Water temperatures above 68ºF (20ºC) are stressful for salmon, and 72ºF (22ºC) is their maximum tolerance limit that forces them to seek cold-water refuge. If salmon cannot find refuge, water temperatures near or above 77ºF (25ºC) are lethal.

On June 1, the State Water Board approved a “temporary urgency change petition” (TUCP) from the Bureau of Reclamation and the Department of Water Resources (DWR) to reduce Delta outflow. By June 2, less than half of the flow released in Redding to the upper reaches of the lower Sacramento River flow (about 8000 cfs, including 7000 cfs from dam releases) was reaching Wilkins Slough, 180 miles downstream. In those 180 miles, more than half the flow was diverted to agriculture. The high early-June water temperatures and low flows are unprecedented for late spring (Figure 2).

Reclamation and DWR’s petition discussed impacts to fish in the Delta. The water temperatures in the Sacramento River at Wilkins Slough in the first week in June show how the Delta and salmon far upstream are connected. The upstream impacts of bad Delta decisions is once again transparent: low requirements for Delta outflow means low flows and lethal water temperatures in the Sacramento River.

An extreme heat period for the Sacramento Valley is expected for the third week of June, and it is still only spring. Winter-run and spring-run adult salmon that made it to the spawning grounds below Shasta and Keswick dams earlier this winter and spring are very likely to experience highly stressful water temperatures (>60ºF) for holding and spawning. Because it is releasing too much agricultural water now, Reclamation is likely to run out of cold water in Shasta by the time that fall-run salmon arrive in Redding in October and November.

The drumbeat of dying salmon will be pounding all summer and into the fall.

Figure 1. Water temperature and Sacramento River flow at Wilkins Slough (RM 125) 5/25-6/7, 2021.

Figure 2. Water temperatures in the Sacramento River at Wilkins Slough (RM 125) in dry years of of the past decade. Values for 2021 are literally over the top. The lethal level for salmon is 77ºF. Stress occurs at >68ºF. Migration ceases at 72ºF.

May Shasta-Trinity Operations Prove Deadly for Salmon

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Back on May 3, 2021, I warned about how bad things were getting for salmon in the Sacramento River below Shasta Reservoir, even compared to drought years 2014 and 2015. With high-volume releases from Shasta storage through almost the end of May, conditions went from bad to worse. Water year 2021 began as a critical drought year after a dry year, with everyone scrambling to save the winter-run salmon in the Sacramento River below Shasta and provide water for downstream Central Valley Project (CVP) contractors. The latter objective has won outright.

Water releases to the upper Sacramento River were even higher in May than April (Figure 1). Releases remained significantly higher than either 2014 or 2015. Such high releases sustained water deliveries to the CVP’s Sacramento River Settlement Contractors at high levels despite reduced allocations for a critically dry year with low storage.

Water temperatures were also significantly higher in May (Figure 2), creating lethal conditions (>53ºF) for eggs of winter-run salmon, which typically begin spawning in April. Peak spawning occurs in June and July, with 60-90% of total spawning by the end of July, even with spawning delayed in warmer years.1 Spawning has likely been delayed in 2021 because of the warmer water temperatures. Delayed spawning also has deleterious effects on egg survival and smolt production.2

The high-volume releases have led to lower total Shasta Reservoir storage at the end of May in 2021 compared to 2014 and 2015 (Figure 3). Inflows to the reservoir (not shown) were similar in the three years – averaging for May just above 3000 cubic feet per second (cfs).

Reclamation has sustained the volume of Shasta Reservoir’s cold-water pool through May 2021 at 2014 and 2015 levels (Figure 4), despite the higher releases and lower storage in 2021. Reclamation did that in part by bypassing power plant releases that draw colder water and instead drawing warmer surface water from “river outlets” nearer the top of the dam (Figure 5).

Reclamation has yet to gain approval for summer operations, but the draft Temperature Management Plan (TMP) it submitted to the State Water Board on May 5 proposed Shasta-Keswick releases of 8000-10,000 cfs. Reclamation’s May 5 draft plan also proposed a target temperature of 56ºF for the 10-mile spawning reach of the Sacramento River just downstream of Keswick Reservoir, around Redding. Such temperatures will lead to high egg mortality this summer. Reclamation’s draft plan included significant inputs of warmer water (>53ºF) originating in Trinity Reservoir and exported to the Sacramento River via the Spring Creek Tunnel from Whiskeytown Reservoir to Keswick Reservoir.

The higher Shasta releases and warmer Trinity water, while proving substantial power generation and water supply deliveries, are depleting already-too-low Trinity and Shasta reservoir storage. They also preclude maintaining the safe water temperature of 53ºF that would minimize egg mortality this summer in the Sacramento River’s spawning reach. Lower storage also results in late summer loss of access to the cold-water pool in Shasta Reservoir.

In a May 21, 2021 letter to Reclamation, the State Water Resources Control Board commented on Reclamation’s draft TMP. The State Water Board’s letter suggested maintaining an end-of-September Shasta target storage of 1,250,000 acre-feet, stating that this would represent a “reasonable balance between temperature control this year, maintaining some carryover storage going into next year, and providing for consumptive water supply needs.” The main problem with the State Water Board’s target 1.25 MAF end-of-September storage is that it would still result in >50% (and potentially much higher) salmon egg mortality. The State Water Board’s target does not correct warm Trinity transfers, excessive Shasta and Trinity releases, and low Shasta and Trinity storage. It would also leave no cold water for Sacramento River fall-run salmon in the fall. The low storage levels may even limit access to cold-water pools in the reservoirs.

Eliminating 80-85% of the warm Trinity transfers and reducing cold water releases from Shasta would save a much greater percentage of the fish in the Sacramento and Trinity-Klamath river systems. It could maintain safe 53-55ºF spawning reach temperatures through the summer, while preserving approximately 500,000 acre-ft of Shasta and Trinity storage for next year.

Such an alternative would cut power production and Sacramento Valley water supply deliveries to roughly half of the levels in 2014 and 2015. In this regard it bears remembering that senior water contractors chose not to absorb some of the water cutbacks in 2020, the first year of the latest drought. Now, drastic delivery cuts are necessary to avoid the third disaster for winter-run salmon in seven years.

For more complete discussion, see CSPA’s May 23, 2021 alternate Temperature Management Plan at https://www.waterboards.ca.gov/waterrights/water_issues/programs/drought/sacramento_river/.

Figure 1. Keswick Reservoir water releases (cfs) in April-May 2014, 2015, and 2021

Figure 2. Keswick Reservoir water temperatures (ºF) in April-May 2014, 2015, and 2021.

Figure 3. Shasta Reservoir storage (acre-feet) in April-May 2014, 2015, and 2021.

Figure 4. Shasta Reservoir cold-water-pool volume (1000s of acre-ft) in water years 2014 (red line), 2015 (purple line), and 2021 (black line). Also shown is average (shaded) and two wetter years. Source.

Figure 5. Shasta Reservoir pool configuration and release sources on May 18, 2021. Temperature Control Device (TCD) gate operation is also shown. Note the combination of turquoise from TCD gates and orange from river outlet water sources provided Shasta releases on May 18.

  1. Source. ↩
  2. For further discussion, see E. Dusek Jennings and Henrdix (2020), Spawn Timing of Winter-Run Chinook Salmon in the Upper Sacramento River.  Available at: https://escholarship.org/uc/item/00c1r2mz ↩

Upper Sacramento River Summer Water Temperatures – Lesson #6: 53ºF Is Key

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Following a series of posts, this is the last post in a series on the lessons learned by the National Marine Fisheries Service (NMFS) from the 2013-2015 drought that devastated Sacramento River salmon populations. This post addresses Lesson #6. The will be the last in the series because the past has become the present, and the focus must now shift to drought conditions and management in 2021 and beyond.1

The best science is that a 53oF daily-average temperature (DAT) is protective of salmon eggs/embryos in their gravel redds in the Sacramento River in the spring and summer spawning season.  But the Bureau of Reclamation, without enough pushback from NMFS and the State Water Board, continues to manage for higher water temperatures in the 10-mile spawning reach of the Sacramento River from Keswick Dam (River Mile 300) downstream to the mouth of Clear Creek (RM 290).2

A 53oF DAT is close to the 55oF seven-day-average-daily-maximum temperature (7DADM) that NMFS cited in its Lesson #6, quoted above.  The Bureau of Reclamation met that target in wet year 2019 (Figure 1).

Protection was compromised in 2020 (Figure 2), as Reclamation only maintained the 53oF DAT at Clear Creek in the peak mid-summer egg and embryo period.  Since the 2019 Biological Opinion, this  has become Reclamation’s dry-year strategy.  This dry-year strategy is a partial improvement over the prior dry-year strategy of 56ºF DAT at Clear Creek that Reclamation employed in 2015 (Figure 3), when there was very low over-summer survival of eggs and embryos, and very little fry and smolt production, of winter-run salmon.

Water temperatures were even higher in May 2021, reaching 58-62oF early in the month (Figure 4).  Such temperatures were high enough to compromise the health and reproductive success of the many pre-spawn adults holding below Keswick Dam.  First, elevated water temperatures delay spawning.  Second, adults have higher disease vulnerability at water temperatures above 60oF.  Third, eggs and embryos from holding adults subjected to water temperatures higher than 60oF have higher pre-hatch mortalities and abnormalities.

With tentative approval by the State Water Board of Reclamation’s draft summer temperature management plan for 2021, we can expect a 56oF DAT at Clear Creek target for the peak June-July egg incubation season.  Such operation allows significant hydropower production and water deliveries from Shasta storage releases, as well as water exports from the Trinity River.  If these were curtailed, Reclamation could achieve a target of 53oF DAT at Clear Creek and save salmon.

Figure 1. Water temperatures May-October, 2019 in the Sacramento River at Keswick Dam-KWK (RM 300), Redding-SAC (RM 295), Clear Creek-CCR (RM 290), and Balls Ferry-BSF (RM 276).

Figure 2. Water temperatures May-October, 2020 in the Sacramento River at Keswick Dam-KWK (RM 300), Redding-SAC (RM 295), Clear Creek-CCR (RM 290), and Balls Ferry-BSF (RM 276).

Figure 3. Water temperatures May-October, 2015 in the Sacramento River at Keswick Dam-KWK (RM 300), Redding-SAC (RM 295), Clear Creek-CCR (RM 290), and Balls Ferry-BSF (RM 276).

Figure 4. Daily average water temperature in the winter-run salmon spawning reach of the Sacramento River below Keswick Dam (KWK – RM 300) and above Clear Creek (CCR – RM 290) in April-May 2021. Safe level for holding adult salmon for reproduction success is 56ºF. The safe level for disease potential in holding adults is 60ºF.

Figure 4. Water temperatures in the Sacramento River at the lower end of the spawning reach above Clear Creek (CCR), May 1-May 30, 2021.