Category Archives: Water Quality

Fall-Run Salmon Spawning near Redding 2021 A tough year for the fall-run salmon spawn

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Fall-run salmon spawn in the fall in the 20-40 miles of the Sacramento River downstream of Keswick Dam near Redding. Numbers of in-river fall-run spawners have declined severely over the past several decades (Figure 1). Declines were worst three years after drought periods (2007-2009, 2013-2015), due to poor egg and fry survival during droughts. A February 2021 post discussed the role of redd dewatering and fry stranding from severe drops in flow and water level (stage) as major drought-related factors in the escapement declines. A 2018 post listed a broader range of factors, including high water temperatures during droughts in addition to stranding.

Stranding was once again a major factor in fall 2021 as water levels near Redding dropped 4 feet from October to November (Figure 2). Further downstream in the lower spawning reach, salmon have also had to contend with high flows as well (Figure 3). High flows (1) encourage salmon to spawn in margin habitat that later dewater, and (2) cause scouring of redds spawned earlier at lower water levels.

In fall of drought year 2021, an additional severe-mortality factor has become apparent. Turbidity/suspended sediment levels in the spawning reach (Figure 4) were at or above lethal levels for salmon eggs and embryo (see December 23, 2021 post) for most of November, a peak spawning period. The late-October record storm and subsequent further rain and runoff have elevated inflows to Shasta Reservoir. As these higher flows have entered the reservoir, they have eroded vast areas of sediment exposed in the drought-depleted reservoir.1 The suspended sediment has carried through the reservoir into the spawning reach below Keswick Dam.

Of positive note, the higher flows (Figure 3) and associated turbidity have likely helped salmon fry that spawned earlier in tributaries like Battle Creek and Clear Creek move downstream in the Sacramento River toward the Delta and Bay.

In summary, fall-run salmon spawning in the most upstream reach of the lower Sacramento River near Redding have faced extreme habitat conditions in 2021. These conditions began with high October water temperatures from a depleted cold-water-pool in Shasta Reservoir. Next came a four-foot drop in water level due to sharply reduced Shasta Reservoir releases. Added to these traumas were egg-smothering levels of suspended sediments from Shasta Reservoir caused by erosion of drought-exposed, decades-old reservoir sediment during a record-level late October storm and subsequent runoff events.

Figure 1. In-river fall-run Chinook adult escapement to the upper Sacramento River 1952-2020.

Figure 2. Streamflow (cfs) and water surface elevation (stage) in the Sacramento River immediately below Keswick Dam October 1 – December 15, 2021.

Figure 3. Streamflow (cfs) and water surface elevation (stage) 50 miles below Keswick Dam October 1 – December 15, 2021. High flows were from tributary inflows below Redding (Cow Creek, Battle Creek, Clear Creek, and others).

Figure 4. Water temperatures and turbidities below Keswick Dam (RM 300) and above the mouth of Clear Creek (RM 290) October 1 – December 15, 2021. Red line depicts literature-based, severe-mortality turbidity level for eggs and embryo salmon for a one-day exposure.

Figure 5. Spring and fall run salmon fry catch at Red Bluff (RM 240) screw traps August – November, 2021. Also shown are nearby Bend Bridge water temperature and flow, and Red Bluff turbidity.

Winter-Run Salmon Spawn near Redding Turbidity and/or Bad Gages Need Fixing

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The summer of 2021 was a real mess in the Sacramento River downstream of Shasta and Keswick dams near Redding.  The winter-run salmon there had to contend with so many stresses it is a wonder any of these salmon survived.  The 2021 cohort will have to rely on hatchery production and, hopefully, a few fish produced through a new program in Battle Creek.

A strange stressor rarely if ever discussed was river turbidity in the lower portion of the 20-mile spawning reach near Redding (Figure 1).  For several days in September, the reported level of turbidity there was well into the range that scientific literature identifies as lethal for eggs and sac fry salmon in gravel beds (Figures 2 and 3).

Assuming gage accuracy, three potential turbidity sources were:  (1) Shasta Lake sediment plumes resulting from the activation of sediment deposits in the reservoir due to water passing through them at low storage levels; (2) sediment releases from Spring Creek Reservoir into Keswick Reservoir, and (3) local high suspended sediment releases from municipal and agricultural discharges.

It is hard to tease out.  The high turbidity readings do not appear to have resulted from sediment in Shasta Lake eroding in a low storage year and washing downstream.  That would have caused elevated turbidity readings at Keswick Dam, which did not appear, although Shasta Dam appears to have released high suspended sediments on September 16 (Figure 4).  The Spring Creek gage was not functioning in September.  Sporadic high turbidities over the next 30 miles of river at Balls Ferry, Jelly’s Ferry, and Bend were common through the summer, with the Bend gage showing the same increase as the CCR gage from September 14-16 (Figure 5).

The three-day event September 14-16 was the main concern.  High turbidities were sustained long enough to have caused serious harm to winter-run in the gravel beds that had begun hatching and emerging after a late spawn (Figure 6).  Low dissolved oxygen in the redds was also a concern, since DO concentrations in redds are generally assumed to be lower than those in the river (Figure 7).

In conclusion, high summer suspended sediment levels in the upper Sacramento River near Redding are a serious concern for spawning winter-run salmon.  If gage readings are accurate, they demonstrate a gross violation of water quality standards for the river.  If the gage readings are not reliable, then  a more rigorous monitoring, assessment, review, and reporting program is urgently needed to protect winter-run salmon and the other beneficial uses of the Sacramento River.

Figure 1. Turbidity (NTUs) in September 2021 in Sacramento River near Redding CA.

 

Figure 2. Suspended sediment risk chart for salmon eggs and embryos. Lethal range denoted are shaded areas with border.

Figure 3. Conversion from NTUs to suspended sediment (mg/l) from two sources.

Figure 4. Turbidity (NTUs) in September 2021 in Sacramento River immediately below Shasta Dam near Redding CA.

Figure 5. Turbidity (NTUs) in September 2021 in Sacramento River at Bend Bridge 50 miles below Keswick Dam near Red Bluff CA.

Figure 6. Winter-run Chinook salmon spawning season conditions in the Sacramento River in 2021. River flows at Keswick Dam (KWK, rm 300) and Bend (BND, rm 250). Water temperatures KWK, BND, and Redding (SAC, rm 290; CCR, rm 280).

Figure 7. Effect of low dissolved oxygen on salmon eggs and embryos accounting for lower dissolved oxygen in salmon redds than river above. Source.

Another Drought Year, Another Temporary Urgency Change Petition to Weaken Delta Water Quality Standards

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The Bureau of Reclamation and California Department of Water Resources (DWR) have proposed another temporary urgency change petition (TUCP) for Delta operations in 2022 (Figure 1, below).  The purported purpose is:

operating the Projects to provide for minimum health and safety supplies…; preserve upstream storage for release later in the summer to control saltwater intrusion into the Sacramento-San Joaquin Delta (Delta); preserve cold water in Shasta Lake and other reservoirs to maintain cool river temperatures for various runs of Chinook salmon; maintain protections for State and federally endangered and threatened species and other fish and wildlife resources; and meet other critical water supply needs.  (TUCP, p. 1).

Under the previous TUCPs in 2014, 2015, and 2021, Reclamation and DWR did not preserve reservoir storage, control salt water intrusion, maintain cold-water in Central Valley reservoirs, or protect listed fish species, but they sure did sustain Central Valley farmers.  In the spirit of being consistent, the latest TUCP makes no mention of the tradeoffs or specific priority criteria.  That’s because, once again, everything in this TUCP is for water contractors.  There is no fresh water to the Bay, its crabs, herring, or anchovies, let alone its salmon, smelt, striped bass, or other fisheries.

The TUCP claims: “The TUCP will support Reclamation and DWR in balancing the competing demands on water supply and is critical to provide some protection of all beneficial uses of the Delta including for fish and wildlife, salinity control, and critical water supply needs.”  (TUCP, Environmental Information, p. 1).  No, it’s simply for contractor water, nothing else.

The TUCP explains: “The continuation of extremely dry conditions in the Delta watershed has resulted in inadequate water supply to meet water right permit obligations for instream flows and water quality under D-1641.”  (TUCP, p. 1).  Apparently, Reclamation and DWR must have forgotten that during extremely dry conditions last year and the year before, Reclamation and DWR gave too much water to their contractors.  They depleted storage to historic lows.  In 2020 and 2021, they knew the snowpack was low.  They knew reservoirs would empty.  They delivered the water anyway.

Well, things are looking really bad: “[T]he conditions of 2021 have left the Projects in a precarious state, with little water to manage even under slight drought conditions next year.”  (TUCP, p. 2).  They knew this was going to happen.  They also knew they could employ their TUCP tricks again.

But fear not.  “[T]he proposed changes in operations will not injure other lawful users of water; will not unreasonably affect public trust resources such as fish and wildlife or other instream beneficial uses; and are in the public interest.”  (TUCP, p. 2).  This is an outright lie, and they think we are suckers enough to believe it.

Figure 1. TUCP Framework, Table from TUCP, p. 2.

Translation of Figure 1: Let no water flow to the Bay.  Open the Delta Cross Channel gates to capture all the out-migrating salmon, steelhead, sturgeon, and steelhead and divert them straight to the Central Delta and water project pumps, along with the fresh water from the Sacramento River.  Let the San Joaquin River die.  Make minimal exports from the Delta because upstream contractors will take all the reservoir and river inputs to the Delta.  Well, not entirely, because upstream contractors will sell much of their water to Southern California users.  The State Water Board will allow transfers through the Delta without the minimal safeguards required for non-transfer exports.  In sum, Reclamation and DWR will deliver to Sacramento Valley contractors about 20 times the water allegedly “saved” by weakening Delta standards, once again disproving the elementary school arithmetic that says to preserve storage, you can’t let more water out of a reservoir than you take in.

Is this a great system or what?

For more on the subject, read https://www.nrdc.org/experts/kate-poole/california-drought.

A Ridiculous Premise

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A recent post from the Center for California Water Resources Policy and Management (Center) discusses the extinction of the Delta smelt.  The post starts by saying, “To be sure, the delta smelt’s numbers are in decline.”  That is a real understatement, but it contains some acknowledgement of the facts.

The author goes on to say, “It might fairly be argued that prime contributors to the delta smelt’s distressed status are California’s resource agencies.”  The ostensible rationale for this attribution is, first, that the resource agencies don’t look for smelt in the right places in the right way.  Second, because the agencies can’t find the smelt, “they have resisted managing the species ‘adaptively’” based on the monitoring that they don’t do.

This ridiculous premise suggests the decline has not been caused by excessive exports of water from the Bay-Delta watershed over the past five decades, but by the resource agencies who don’t know where to find and thus protect the smelt.

The author argues: “The agencies persist in mobilizing trawler-based open-water fish surveys, originally intended to census juvenile striped bass, as their primary means of monitoring delta smelt and the Delta’s other protected fish species.”  This statement is simply untrue.  To provide better coverage of “open-water” pelagic smelt, the Interagency Ecological Program (IEP) in recent decades added the Larval Survey, the 20-mm Survey, the Kodiak Trawl Survey, and most recently the Enhanced Delta Smelt Monitoring Program (EDSM).   All of these surveys, plus the historic Fall Midwater Trawl and Summer Townet Surveys (and 50 years of Delta Export Fish Salvage Surveys), show the smelt’s catastrophic decline and march toward extinction.

But the author insists that the smelt are out there somewhere.  “The surveys sample neither the relevant habitat strata used by those fishes nor the extent of their ‘closed’ populations, which would allow for estimates of the sizes of their populations.”  If the smelt are out there in “closed populations” whose numbers would change the conclusions about the smelt’s catastrophic downward trend, then surely the author and the water purveyors who have a vested interest in finding those populations can muster some evidence and show the agencies and the rest of the world where to look.

Basic review and analyses of the available information show the decline of Delta smelt is highly associated with increasing exports and associated factors (see my many posts on this subject).  The partial truth in the notion that the resource agencies have been complicit in the decline of Delta smelt stems from agency inaction to cut back those exports consistent with biological sustainability.  Agency managers don’t lack information and scientific method.  They lack the political courage to deploy them.

Lake Shasta – Late Fall 2021

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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.