Author Archives: Tom Cannon

Are Striped Bass Next to Go? 2021 Update

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The prognosis for Bay-Delta and California striped bass could not be much worse. Numbers of stripers salvaged at the south Delta pumping plants in 2021 are down to or below 2014-2015 levels.1 Like many other species that spend all or part of their lives in the Delta, striped bass are on a downward spiral. Good water years are not providing enough population rebound to offset devastating lack of recruitment in dry year sequences.

In my report on the status of striped bass in 2016, stripers had suffered terribly in four years of drought (2012-2015). By 2019, the prognosis was still not good after a sequence of wetter water years (2016-2019) that were below normal, wet, below normal and wet.

Now, the summer-to-fall recruitment relationship (Figure 1), with its strong relationship between the summer index and fall recruitment, shows that dry year 2020 recruitment was as low as during the critically dry drought years 2014 and 2015. In the critically dry drought year 2021, late spring net catches are at historic lows.2 If the summer-to-fall recruitment relationship holds in 2021, striped bass are circling the drain as the next fish species to be lost in the collapsing Bay-Delta ecosystem.

Figure 1. Striped bass Fall Midwater Trawl Survey Index (log10[index+1]) versus prior Summer Townet Index (log10). Select years labeled, with color of number showing year type: blue=wet, green=normal, and red=critically dry.

Butte Creek Spring-Run Chinook Salmon in Peril

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Butte Creek DeSabla – Centerville Project options1 could help save the salmon

Butte Creek’s spring-run salmon are dying in droves (over 12,000 carcasses of un-spawned adults counted so far in summer 2021) in their over-summering reach upstream of Centerville. A huge run of the most important core element of the California Central Valley Spring-Run ESU is being wiped out by low flows and high water temperatures.

This year’s spring-summer salmon migration and holding water temperatures have been about 5ºC higher than normal (Figure 1). Average daily water temperatures where adult salmon have been holding were over 20ºC for a solid month from the third week in June through the third week in July. Though the immediate cause of this year’s die-off is not known, these temperatures can lead to disease and even hypoxia in overcrowded conditions. Streamflows have also been well below average in 2021 (Figure 2). This is a consequence of reduced snowmelt and of reduced water available from PG&E’s Hendricks diversion from the West Branch of the Feather River, part of PG&E’s DeSabla-Centerville Hydroelectric Project.

After decades of successful recovery progress, the recent trend for spring-run salmon in Butte Creek is downward (Figure 3). The huge loss this summer of what was to be a recovery run will make the trend worse.

PG&E has operated the DeSabla – Centerville Project (Figure 4) for a century, but decided in 2017 to withdraw its application for a new license to continue operating the project. PG&E is in the process of trying to sell the project, but after four and a half years, the sale, and the suitability of the prospective buyer, are not certain. Meanwhile, needed improvements to the project have been on hold. In particular, infrastructure to reduce heating of water in a small project reservoir just uphill from DeSabla Powerhouse on Butte Creek could have helped reduce water temperatures in Butte Creek this year.

Without the 40-100 cfs of cool summer water available from the West Branch of the Feather River via the DeSabla project, water temperature and flow conditions would be even worse, and sustaining spring run in Butte Creek might not be possible. Therefore, some stakeholders have suggested that the State of California, specifically the Department of Water Resources, should consider taking over the DeSabla project to secure cool water from the West Branch Feather River for the immediate future.

An additional phase of actions on Butte Creek could entail removing the Lower Centerville Diversion Dam, a low-head dam on Butte Creek just downstream from the DeSabla powerhouse (Figure 4). Removal of the dam and diversion could be a first step in allowing access to many miles of upstream spawning and rearing habitat on Butte Creek presently blocked by the dam. It is likely that several natural barriers might also need to be modified.

As climate change strikes California with an accelerating vengeance, options to protect and recover California’s salmon are becoming fewer and more difficult. Salmon are dying in greater numbers and with more frequency on the floor of the Central Valley. Projects and alternatives to move salmon back into higher elevation habitat seemed far-fetched or exorbitant a decade ago. They require a fresh and more expansive look today.

Figure 1. Water temperature recorded April-July 2021, plus recent four-year average.

Figure 2. Streamflow recorded April-July 2021, plus 90-year historic average.

Figure 3. Butte Creek annual spring-run salmon snorkel counts. Data Source: CDFW.

Figure 4. Modified DeSabla Project concepts. Solid red line is continued transfer of West Branch of Feather water via DeSabla powerhouse. Red “X”s denote options to remove diversion dams and power canals.

 

  1. The Central Valley Salmon and Steelhead Recovery Plan (NMFS 2014) includes an action to evaluate a Butte Creek water management option for the PG&E DeSabla-Centerville Hydroelectric Project to determine the flow conditions that optimize coldwater holding habitat and spawning and rearing habitat. ↩

Feather River Salmon Recovery Responsibilities, Commitments, and Recommendations

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The State Water Project (SWP) is not protecting salmon in the Feather River.  The Feather River’s once-prolific populations of wild spring-run and fall-run salmon have been replaced by smaller numbers of hatchery fish of inferior genetic composition.

The fact that the replacement of wild fish by hatchery fish plagues all salmon stocks in the Central Valley Evolutionarily Significant Units (ESUs) is no excuse.  The California Department of Water Resources (DWR) has many responsibilities and commitments to protect Feather River salmon under the SWP’s project’s hydropower license, water rights, and other permits, and more generally under the public trust doctrine and the reasonable use doctrine in the state constitution (Article X, Section 2).  The SWP has not met these responsibilities or related commitments since the SWP’s completion in the 1960s.

Neither Feather River nor Central Valley salmon recovery can be achieved without cleaning up the mess in the lower Feather River.  This fact is recognized widely in salmon recovery plans, federal biological opinions, State incidental take permits, and even in part in the Oroville Settlement Agreement for the relicensing of the SWP’s hydroelectric facilities at Oroville.  DWR has made many promises and commitments toward salmon recovery, but has realized very few.  While DWR has spent billions on upgrading project infrastructure, especially after the 2017 spillway failure, it has spent little toward salmon recovery.

So how should DWR focus its salmon recovery process for the Feather River at this point?

Well, most certainly on mandatory provisions in the soon-to-be issued FERC hydropower license and related State Board water quality certification.  Also, on existing or needed conditions in its water right permits that extend beyond the small geographic scope of the FERC license.  The next focus should be on  the “Habitat Expansion Agreement for Central Valley Spring-Run Chinook Salmon and California Central Valley Steelhead” (HEA) that DWR and Pacific Gas and Electric Company (PG&E) agreed to during the Oroville relicensing.1 There are also requirements in the Reasonable and Prudent Measures in the 2016 federal biological opinion for the Oroville relicensing.

The overall focus should be on recommendations in specific salmon recovery plans pertaining to the project.

Below are my recommendations for top priority actions for Feather River salmon recovery from among the sources mentioned above.

Spring-Run and Fall-Run Salmon Introgression

A primary focus and priority should be on minimizing introgression of the spring-run and fall-run salmon populations in the hatchery and natural spawning area of the 8-mile Low Flow Channel (LFC) downstream of Oroville Dam.

For the natural spawning area of the LFC, one option is a segregation weir at the lower end above the Thermalito Afterbay outlet that would provide for selective passage of selected adult spawners into the spawning area.  Similar weir systems are operated in lower Battle Creek and lower Butte Creek.  For example, the weir could provide seasonal passage to accommodate only spring-run spawners that arrive earlier than fall-run.  The fall-run would be forced to spawn downstream of the afterbay outlet in the High Flow Channel (HFC) where habitat conditions, especially water temperatures, would be more suitable later in the year when fall-run salmon are spawning.  The weir could also trap fish to allow direct segregation or egg taking, or trapping-and-hauling of selected adults or offspring produced in the LFC.

The hatchery program should focus on broodstock selection and hatchery operations that produce returning adult spring-run and fall-run salmon of the highest genetic integrity possible.   It should also operate to limit straying of Feather River origin hatchery salmon.  Hatchery operations should also focus on strategies for smolt releases that provide the greatest return while limiting effects on wild salmon.  Otherwise, the Feather River Fish Hatchery Improvement Program (Article A107 of the Oroville Settlement Agreement) should be implemented.  This program sets specific targets for hatchery temperatures, requires development of a hatchery management program (including a Hatchery and Genetics Management Plan), potential installation of a water supply disinfection system, and funding for annual hatchery operations and maintenance.

Lower Feather River Habitat Improvements

There are many potential habitat improvements in the LFC and in the High Flow Channel (HFC, the lower Feather River downstream of the outlet of Thermalito Afterbay).  Habitat improvements could provide significant benefits to adult salmon holding and spawning success, and wild fry survival and smolt production.  One general category is water quality (i.e., water temperature) and streamflow management through improved infrastructure and operations strategies of flow releases to the LFC and HFC.  The second category is improvements to the physical (non-flow) habitat features, including channel configuration (depths, velocities, and substrate composition) in both the LFC and HFC.

Flow and Water Temperature

Adult spring-run salmon migrate in spring to the lower Feather River, then hold in deep pools over the summer to spawn in early fall.  Adequate flows and cool water temperatures are essential elements of (1) spring adult migration habitat in the lower Feather River and (2) over-summering holding habitat.  Without adequate flows for migration and holding, adult salmon are prone to disease and pre-spawn mortality, poor reproductive success, or lower survival of eggs.  Water temperatures should be no higher than 65oF during migration and 60oF during holding to minimize such detrimental effects.  Water temperatures in the HFC (or LFC) should not exceed 65oF in spring (Figure 1).  Water temperatures in the LFC should not exceed 60oF in summer (Figure 2).  The various planning documents outline potential options to reduce water temperatures in the LFC and HFC.  These include measures to sustain Oroville Reservoir’s cold-water pool and reliably release water from it.  They also include measures to keep water in the Afterbay complex cooler prior to release into the HFC.  Still other measures may include limiting release of water from the Afterbay through a variety of modifications to facilities and operations.

Physical Habitat Features

The Biological Opinion and Settlement Agreement for the Oroville relicensing include prescriptions for the restoration and enhancement of lower Feather River salmon habitat, consistent with the NMFS Salmon Recovery Plan:

  1. Design and build infrastructure and stream channel features that will allow for segregation and reproductive isolation between fall-run and spring-run Chinook salmon naturally spawning in the LFC of the Feather River.
  2. Develop a spawning gravel budget and introduction plan, and implement the plan.
  3. Design, construct, and maintain side-channel and off-channel habitats for spawning and rearing salmon and steelhead.
  4. Obtain river riparian and floodplain habitat through easements and/or land acquisition as needed, allowing the river room to grow and move as necessary to provide key transition habitats, and to minimize degradation (such as channel incisions/filling and substrate armoring) of existing high quality habitat features. Provide a balance between the needs of flood conveyance, recreation, and aquatic, riparian and floodplain habitat in and near an urban environment.
  5. Design, build, and maintain channel features that provide optimum habitat, fish passage, and flood control necessary to minimize scour and erosion. High-flow floodplain channels may be such a feature.
  6. Provide deeper holding habitat and cover for adult over-summering spring-run salmon in the channel habitat features described above. Such habitat is often larger pools with a large bubble curtain at the head, underwater rocky ledges, and shade cover throughout the day. Adult spring-run Chinook salmon may also seek cover in smaller “pocket” water behind large rocks in fast water runs.

Benefits to Other Species

Efforts to improve salmon habitat in the lower Feather River will benefit other important native fish.

The lower Feather River is home to other significant fisheries resources including the following:

  • Spawning anadromous steelhead – spawning is concentrated in Low Flow Channel below the Fish Barrier Dam in winter and spring.
  • Steelhead eggs in gravel redds are concentrated in Low Flow Channel below the Fish Barrier Dam in winter and spring.
  • Steelhead yearling smolts rearing occurs in the Low Flow Channel and the High Flow Channel in winter and spring.
  • Steelhead fry rearing occurs in the Low Flow Channel and the High Flow Channel in winter and spring.
  • Spawning of green and white sturgeon occurs in spring in the High Flow Channel.
  • Sturgeon eggs are found in rock crevices of the river bottom in the High Flow Channel in spring.
  • The newly hatched larvae and fry of sturgeon occur on the river bottom in the High Flow Channel in spring.
  • Resident trout and non-salmonid fish occur year-round throughout the lower Feather River.

Habitat Expansion Agreement – Final Habitat Expansion Plan

The Oroville Project Habitat Expansion Agreement (HEA) requires creation of habitat suitable to increase populations of Central Valley spring-run Chinook salmon by a minimum of 2000 adults.  The Habitat Expansion Plan proposed by DWR and Pacific Gas and Electric Company (PG&E) focuses on physical habitat improvements to the Lower Yuba River to benefit spring-run Chinook salmon.   According to DWR and PG&E, this would develop a viable, self-sustaining population of spring-run Chinook salmon below Englebright Dam.

In my opinion, this is a big mistake.  The lower Yuba River below Englebright Dam has many of the same problems as the lower Feather.  Its spawning habitat already has capacity for many more spring-run salmon than are currently utilizing it.

A much better option is saving the Butte Creek spring-run salmon, the largest core population of the CV Spring Run Salmon ESU.  A first phase of a Butte Creek recovery program would be to secure Butte Creek’s supply of cold Feather River water for the immediate future.  PG&Es decommissioning of the DeSabla-Centerville Hydroelectric Project would potentially eliminate or reduce cold-water inputs from the West Branch of the Feather River to Butte Creek.  The DeSabla Project moves water from the West Branch Feather in canals for release into Butte Creek through the DeSabla Powerhouse.  This additional, relatively cool water provides holding and spawning habitat that presently sustains Butte Creek’s spring-run salmon and supports Butte Creek’s fall-run salmon and steelhead.

A second phase of a Butte Creek recovery program would entail removal of the Lower Centerville Diversion Dam, a low-head dam on Butte Creek just downstream of the DeSabla powerhouse (Figure 3).  Since 2014, this dam has not diverted any water.  Removal of the dam and diversion, and potentially removal or modification of other fish passage improvements at natural barriers if needed, could allow access to many miles of upstream spawning and rearing habitat on Butte Creek.  This would truly expand spring-run habitat in the Central Valley.

Summary and Conclusion

Feather River salmon recovery should proceed through improvements in flow, water quality, and physical habitat, project operations and facilities, and hatchery operations and facilities.  Habitat expansion for spring-run salmon should focus on saving the existing run of spring-run salmon on Butte Creek and expanding their upstream range, not on physical improvements to the lower Yuba River.

Figure 1. Water temperature in the lower Feather River within the HFC in spring 2020 and 2021. Red line is upper water temperature safe limit for migrating salmon.

Figure 2. Water temperature in the lower Feather River within the LFC, 2013 and 2021. Red line is upper water temperature safe limit for pre-spawn, adult holding salmon.

Figure 3. Map of PG&E DeSabla Hydroelectric Project features on Butte Creek and the West Branch of the Feather River.

Reclamation Has Done Everything it Could to Kill off Salmon this Summer. Now it Plans to Finish the Job.

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The Bureau of Reclamation’s plan for Shasta-Trinity operations in summer of drought year 2021 was founded on killing off the salmon in the upper Sacramento River to sustain hydropower and water deliveries. So far, it has been wildly successful. Now Reclamation plans to finish the job on winter-run, spring-run, and fall-run salmon.

First, in late April and early May, Reclamation released an extraordinary amount of warm water from Shasta Reservoir for contractor water deliveries. These early releases compromised and delayed early winter-run spawning and late season smolt migration to the ocean (#1 in Figure 1). The early releases also unnecessarily reduced already critically-low Shasta storage, compromising the summer storage and cold-water-pool supply.

Second, Reclamation’s late May and early June releases of colder water (it ceased warm surface releases) encouraged spawning under falling flows, dropping river stage, and marginal spawning temperatures (Figures 1 and 2).

Third, increasing cold-water releases in late June and July (Figure 1) encouraged further spawning under rising and higher water levels (Figure 2).

Now, Reclamation plans to reduce releases of water in August and September (Figure 1). The water will get steadily warmer, because most of the cold water is gone. The combination of warm water and sharply dropping river stage (Figure 2) will complete the demise of this summer’s delayed winter-run spawn. The warmer water temperature will kill the late spawned eggs/embryo. A 4-foot drop in water level will strand and dewater many of the redds. The loss of Shasta’s cold-water-pool will also compromise the spring-run and fall-run spawning runs.

And finally, Reclamation will draw Shasta Reservoir down to historically low levels this fall. This will place Reclamation in a great position to kill all the salmon next year, too.

Figure 1. Flow and water temperature below Keswick Dam in the upper Sacramento River near Redding through late July 2021, along with Reclamation’s projections for August-September.

Figure 2. River stage below Keswick Dam in the upper Sacramento River near Redding through late July 2021, along with Reclamation’s projections for August-September.

 

Shasta Dam Update – July 18, 2021

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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 ↩