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.

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

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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).

Results

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).

Analysis

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. ↩

Addendum to the State Drought Plan — August 31, 2021, Part 1: the Art of the Euphemism

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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, stating:: “Project operations are still tracking with the operations forecast included in the July Drought Plan addendum. August has been fairly typical, with operations primarily controlled by system-wide depletions and Delta salinity.”  This is like a dispatch from the captain of the Titanic saying: the ship was tracking course since the last report, and yes, it hit the iceberg.  As is fairly typical under such circumstances, it sunk, primarily due to the hole in the hull.

The “depletions” that caused the current gaping hole in Shasta Reservoir’s storage and the resulting lethal downstream water temperatures, to reach full effect in September, didn’t just happen.  These glibly described “depletions” are primarily the excessive deliveries to Sacramento River Settlement Contractors to which this blog, CSPA, and others have been vociferously objecting since March.  And, of course, what is sunk is not the good ship Reclamation.  It is the year’s cohorts of Sacramento River salmon, just like in the disasters of 2014 and 2015.

Shasta-Keswick Storage Releases to the Upper Sacramento River

In 2021, Reclamation has not heeded the lessons learned in the 2013-2015 drought.  In 2021, Reclamation has not even implemented the feeble salmon-saving drought actions it applied in 2014 and 2015.

  1. April-May Keswick storage releases were higher in 2021 than 2014 (+257 TAF) and 2015 (+185 TAF) (Figure 1). Reclamation restricted releases in 2014 and 2015 in April-May to preserve Shasta’s cold-water pool.  It did no such thing in 2021.
  2. The higher releases in 2021 led to depleted storage in Shasta Reservoir (Figure 2). Storage at the end of May 2021 was 200 TAF lower than in May 2014, after having been 200 TAF higher at the beginning of April.
  3. The measures to maintain steady flow/stage and water temperature prescribed for drought year 2015 were not applied in 2021. In 2021 operations reverted to the 2014 regime, or worse.

Spawning Conditions for Winter Run Salmon

Winter-run salmon spawn from April to August, with a June-July peak in the ten miles of river downstream of Keswick Dam.  Early season (April-May) flow and water temperature conditions were erratic in 2014, 2015, and 2021 (Figures 1-4).  Rising flows and water temperatures stimulate the spawning migration and maturation leading up to the spawn.  Water temperature above 65ºF hinder migrations and stress adult spawners.  Water temperatures above 60ºF delay spawning and stress eggs in female salmon and eggs/embryos in redds.

  1. Conditions in 2014 proved devastating for the salmon spawn because of high water temperatures in late summer as Reclamation lost access to Shasta’s cold-water pool due to low storage. In addition,  a late summer drop of 2-3 feet in the stage height of the Sacramento River downstream of Keswick Dam caused spawning interruption and redd stranding (Figure 3).
  2. Despite concerted efforts in 2015 to retain storage, to maintain steady flows (and stage), and to sustain colder water releases, water temperature proved too high (>55ºF) for good egg/embryo survival. The lesson learned led to the current target for good survival of <53ºF in Keswick releases.
  3. Operations in 2021 were devastating, starting with high spring water temperatures, followed by a short period of good conditions in late June designed to stimulate spawning, before higher water temperature (Figure 4) and falling stage height greeted later winter-run spawners and egg/embryos/fry in redds.

Migration Conditions for Adult Salmon in Lower Sacramento River

Water temperatures in the lower Sacramento River 100-200 miles downstream of Shasta Dam remained far from typical in 2021 (Figure 5).  For the most part, water temperature from May through August were above the minimum stress level of 68ºF, and above the 72ºF avoidance level for weeks at a time.  These conditions not only affected the late migration of winter-run salmon, but also that of the spring-run (in spring) and fall-run (in summer) who spawn in early fall.

Summary

In summary, Reclamation’s operations of Shasta Reservoir have been as bad in 2021 as they were in 2014 and 2015, or worse.

Future posts will discuss more aspects of the failures of Reclamation’s Shasta operations in 2021.

Figure 1. Water releases from Keswick Dam (river mile 300) to the lower Sacramento River near Redding CA, April-August 2014, 2015, and 2021.

Figure 2. Shasta Reservoir storage (acre-feet) April-August in 2014, 2015, and 2021.

Figure 3. River Stage in Sacramento River below Keswick Dam April-August in 2014, 2015, and 2021.

Figure 4. Water temperature in Sacramento River below Keswick Dam April-August 2014, 2015, and 2021.

Figure 5. 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.

A Tale of Two Below-Normal Water Years – 2016 and 2020 More Shasta Reservoir Solutions to Save Salmon

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Water years 2016 and 2020 were below-normal water years in the Central Valley. Water year 2016 followed three critically dry, drought years, whereas 2020 followed two wet years (2017 and 2019) and one normal (2018) year. So one might assume that 2020 would have been better for Sacramento River salmon than 2016. But it ain’t so – because two different federal administrations were managing Shasta operations. The Trump administration’s policy to “maximize deliveries” of water that began in 2020 had consequences that turned deadly for salmon in critically dry 2021.

First and foremost, Shasta Reservoir storage in 2016 was surprisingly about 500,000 acre-feet or more higher than it was in 2020 after the first of April (Figure 1). Although water year 2020 started out nearly 2 million acre-feet (MAF) higher after a wet year, Shasta storage rose sharply in 2016, nearly filling (4.6 MAF capacity) with winter rain. But the real question is why reservoir storage did not recover in spring 2020. The reason is simply that in 2020, high spring and early summer reservoir releases for water deliveries released water from Shasta almost as fast as it was coming in (Figure 2). If in mid-March, when the reservoir storage was at 3.5 MAF in both years, similar storage-release constraints were in place in 2020 as in 2016, then 2020 would have ended the summer about 500,000 acre-feet higher than it did, near the 2016 storage level (Figure 3).

As a consequence of the storage difference and summer reservoir management, water temperatures downstream of Shasta Reservoir were significantly higher in 2020 than they were in 2016 (Figures 4 and 5). One reason for this was a much reduced volume of the Shasta Reservoir cold-water pool in 2020 compared to 2016 (Figure 6).

In conclusion, the Bureau of Reclamation managed water for winter-run salmon in normal water year 2016 much better than it did in normal water year 2020. Knowing the reservoir would likely not fill in 2020, Reclamation should have deployed a more conservative spring and summer release pattern, similar to what it did in 2016, to sustain cold-water releases from the reservoir through the summer and fall.

Figure 1. Shasta Reservoir water storage (AF) in 2016 and 2020.

Figure 2. Keswick Reservoir to the lower Sacramento River from April-October in 2016 and 2020.

Figure 3. Shasta Reservoir storage in 2016 and 2020 along with author-calculated adjusted release for 2020 if flow release pattern in 2016 (Figure 2) had been employed.

Figure 4. Water temperature below Shasta Dam April-October 2016 and 2020.

Figure 5. Water temperature below Keswick Dam April-October 2016 and 2020. Note target safe water temperature for salmon spawning and egg incubation is 53ºF.

Figure 5. Water temperature below Keswick Dam April-October 2016 and 2020. Note target safe water temperature for salmon spawning and egg incubation is 53ºF.

Figure 6. Coldwater pool volume (TAF) in Shasta Reservoir in 2016 and 2020, and other years.

Classification of Water Year Types

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At the 2021 Bay-Delta Science Conference, Department of Water Resources (DWR) engineers discussed the results of their modeling study on classification of Central Valley water-year types that define operations of state and federal water projects.1 The study recognized the need to adjust the rules because of climate change and associated changes in human and environmental demands on water supplies. “Iterations of the model become a water system stress test under different incremental changes of climate.”

The study focused on the classification of water years for the Sacramento and San Joaquin rivers: currently, these are critically dry, dry, below normal, above normal, and wet. The study suggests there is likely to be a higher frequency of critical and below normal years, and a lower frequency of wet and above normal years, because of rising temperatures. The study suggests adjusting the year type criteria downward to increase the frequency of drier year-type designations. Sensitive parameters in the model included Delta inflows and outflows, Delta exports, and Delta salinity.

The study suggested that changing the classification criteria would generally result in higher Delta inflows and outflows, which would help reduce the salinity effects of sea-level rise due to climate change. The theory was evidently that DWR and the Bureau of Reclamation set export levels lower in drier water-year types. If DWR and Reclamation actually set lower exports and north-of-Delta deliveries in drier water years, there could actually be some benefit. But right now, most of those levels are discretionary and not enforceable criteria. And under existing rules, Delta inflow and outflow requirements also become progressively lower with drier water year types.

The logic behind supposed aquatic benefits to increasing the relative frequency of drier water year types is tortuous at best. The real outcomes would depend on the implementation of the other variables that are the legs of the water management stool: flow, storage, and deliveries. Those outcomes will be measured indirectly by such metrics as water temperature and salinity, and more directly by the quality of the fisheries produced.

The State Water Board’s update of the Bay-Delta Water Quality Control Plan proposes to severely limit reliance on water year types. On the other hand, the Bay-Delta Plan to date has not addressed the specifics of droughts and dry year sequences. Whether called water year types or something different, managing water is dependent on annual and inter-annual conditions.

One example of a different approach to watershed-specific water-year-type criteria is modification of reservoir storage requirements according to various year-type conditions. In a recent post, I suggested a sliding scale of minimum end-of-year (end of November or December) storage criteria for Folsom Reservoir on the American River (Figure 1). Similar criteria are relevant to Oroville Reservoir on the Feather River (Figure 2). Maintaining minimum reservoir storage criteria would go a long way toward protecting all beneficial uses. To date, both DWR and Reclamation have doggedly resisted such criteria.

Figure 1. Folsom Reservoir daily-average storage (acre-feet) 2000-2021. Recommended minimum storage criteria (end of November) are shown by circles: blue for high-storage years; light blue for intermediate-storage years; yellow for low-storage years. Red arrows are years that grossly exceeded such criteria.

Figure 2. Oroville Reservoir daily-average storage (acre-feet) 2012-2021. Recommended minimum storage criteria for end of November are shown by red circles.

A Tale of Three Critically Dry Years – More Shasta Reservoir Solutions to Save Salmon

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Shasta Reservoir is low again at the end of summer in drought year 2021.  The pattern is very similar to critically dry years 2014 and 2015 (Figure 1) that resulted in the loss of access to Shasta’s cold water and failure of the winter-run salmon spawn in the summer.  Year 2021 is leading to another failure of the winter-run salmon spawn and fry production.  Shasta’s cold-water pool supply is depleted, and river releases are too warm (Figure 2).  Water temperatures downstream of Shasta held in 2020 (Figure 2) despite high water releases (Figure 3), because 2020 had 1 million acre-feet more storage at the beginning of the year than either 2014 or 2021 (Figure 1).

The three disaster years could have had different outcomes if as little as 300,000 acre-feet of additional storage had been available in 2013 and spring 2021.  If at the end-of-year 2013, storage had been 2 MAF rather than 1.7 MAF, and the additional 300,000 AF been carried into 2014 and 2015 and then used to protect fish, the 2014 and 2015 disasters could have been averted.  If the spring releases in 2021 had been minimized as in other drought years, then the 2021 disaster could have been averted.

One reasonable strategy for Shasta Reservoir’s storage problems is minimum end-of-year storage prescriptions based on initial storage and water year type, and limiting releases in spring after dry years when storage is at or below 2 MAF.  Goals should be set for the next year based on initial conditions end-of-year storage (Figure 1).  As stated in a previous post, it is no longer enough to set end-of-September storage targets.  Climate change means in part that more autumn months are very dry. Exports in the fall (and a transfer season now extended through November) pull down CVP storage or at least slow reservoir refill.  Storage at the end of November or end of December needs to an explicit part of the carryover calculus.  Figure 1 shows end-of-November as the requirement.

Proposed Operating Storage Rules

  • Wet Year – High ending storage required (3 MAF minimum e-o-y storage – 11, 17, 19);
  • After Wet Year – if following year turns normal or dry, but reservoir fills, target is 2.5 MAF e-o-y storage (12, 16, and 18); if reservoir does not fill, target is 2.0 MAF (13, 20);
  • Critical Year – if critically dry with low storage, target e-o-y storage is 1.25 MAF (14, 15, 21).

Proposed Operating Release Rule

  • After a Drier Year – if storage is at or below 2 MAF at the beginning of a year and is below 2.5 MAF by the end of March, then April-May Shasta Reservoir releases should be limited to sustain and support in achieving higher summer storage and an e-o-y storage of 1.25 MAF. This decision needs to be made in April, based on a conservative runoff forecast methodology.

 Past Performance 2011-2021

  • 2013-2015 – Critical Dry Years – In 2013, storage fell about 300,000 AF below the 2 MAF e-o-y target, leaving 2014 e-o-y at a deficit that carried over into 2015. That led directly to the loss of access to Shasta’s cold water in summer-fall 2014 and 2015.
  • 2021 – Critical Dry Year – In 2021, Shasta Reservoir failed to regain its starting storage, not because 2020 ended from a storage deficit, but because of excessive releases in April and May (Figure 3).

 In summary, the 2014, 2015, and 2021 salmon production disasters in the upper Sacramento River salmon spawning reach below Shasta Reservoir could have been averted by following simple reasonable criteria for end-of-year minimum storage and stricter criteria for storage releases in spring of drought years.   This presumes, of course, that Reclamation would not have otherwise misused the water thus saved.

Figure 1. Shasta Reservoir daily-average storage levels in acre-ft, 2014-2021. Red circles are suggested minimum target criteria for those year types. Red arrows are years in hindsight the criteria were not met.

Figure 2. Keswick Reservoir release daily-average water temperature, May-October 2014, 2020, and 2021. Target maximum release temperature for salmon spawning in the 10-mile spawning reach below Keswick is 53oF (red line). Note Reclamation’s 2021 stated plan was to maintain target temperatures only at peak spawning in late June, but not in the early (late Apr-early June) or late (July-August) portions of the spawning period. Note also the lost access to the cold-water pool in September 2014 and October 2020. Access to the cold water is being lost in mid-August 2021.

Figure 3. Shasta Reservoir releases April-October in years 2014, 2020, and 2021. Note high releases in spring 2021 compared to 2014 in April-May period (difference was 240,000 acre-feet).