Enhancing Pelagic Habitat Productivity in the North Delta Is it too late to save the Delta smelt?

The Bureau of Reclamation recently released an Environmental Assessment for the Sacramento Deep Water Ship Channel Nutrient Enrichment Project. The proposed project would directly release nitrogen nutrients into the Ship Channel, which runs from West Sacramento to Cache Slough, north of Rio Vista.  The project is designed to stimulate plankton blooms in the North Delta as part of the Delta Smelt Resilience Strategy, which describes the goal as follows:

The purpose is to determine if the addition of nitrogen can stimulate plankton (fish food organisms) production in a section of the ship channel, which is isolated from the Delta in terms of water flow.

Adding nitrogen to the ship channel will indeed stimulate plankton productivity.  Only a few miles away, regional governments have spent decades in removing nitrogen (most recently, ammonia) from the effluent of the Sacramento Regional Wastewater Treatment Plant to reduce production of blue-green algae in the Delta.  The City of West Sacramento already seasonally releases high nutrients, metals, and salts into the Ship Channel.  Adding more nitrogen could easily increase toxic blue-green algae problems in the Delta, similar to the bloom that recently led to the recreational closure of southern California’s Diamond Valley Reservoir, which receives Delta water.

There is higher plankton productivity in the Ship Channel than in nearby Delta channels because the Ship Channel has longer residence time, higher nutrients,  and higher water temperatures.  The broken gate on the Ship Channel’s northern entrance contributes to these conditions.  However, lack of circulation also leads to nitrogen depletion and declining plankton production, and there is limited seasonal replenishment of nitrogen.

The Delta Smelt Resilience Strategy is considering increasing flows into the north Delta from the Colusa Basin Drain, Fremont Weir, and the Ship Channel to stimulate Delta plankton blooms.  The biggest problem with these sources is high spring-through-fall water temperatures (Figures 1-3).  Water temperature is certainly the greatest limiting factor in the north Delta for Delta smelt; adding nitrogen will not fix this problem.

Fixing the gate at the north end and allowing cooler Sacramento River water (strong American River influence) into the channel (Figure 4) would reduce water temperatures in the Ship Channel.  Just a few degrees can be life or death for Delta smelt.  Increased entry into the Ship Channel of Sacramento River water would also introduce more nitrogen, potentially reducing the need to fertilize the Ship Channel with crop dusters.

Figure 1. Water temperature in the Yolo Bypass downstream of the entrance of the Colusa Basin Drain.

Figure 2. Water temperature in the Sacramento River Deep Water Ship Channel.

Figure 3. Water temperature in the lower Yolo Bypass toe drain canal near Liberty Island.

Figure 4. Water temperature in the Sacramento River near Freeport downstream of the entrance to the Sacramento River Deep Water Shipp Channel.

Gross Violation of Water Quality Standards for Water Temperature in Lower Sacramento River Further Degradation of Salmon Habitat

Water temperatures in the lower Sacramento River over the past month have often exceeded water quality standards that protect salmon and other beneficial uses (Figures 1 and 2).  Water temperatures at or above the standard of 68oF adversely affect adult and juvenile salmon.  Water temperatures can meet the standard if the Bureau of Reclamation maintains flow in the Sacramento at Wilkins Slough at 6000-8000 cfs, depending on air temperature.  The Bureau of Reclamation has maintained such flows in the past to meet water quality standards and terms in its water rights permits (Figure 3).  Shasta Reservoir water storage is 102% of normal as of June 18, 2018.  Water diversions from the Sacramento River upstream of Wilkins Slough are approximately 6,000 cfs, with 100% allocation to CVP contractors under water right permits.  For more on the effects on salmon, see past posts.

Figure 1. Sacramento River flow and water temperature at Wilkins Slough in lower Sacramento River: mid-May to mid-June 2018. Red line denotes water quality standard. Source: CDEC.

Figure 2. Sacramento River water temperature at Verona in lower Sacramento River: mid-May to mid-June 2018. Red line denotes water quality standard. Source: CDEC.

Figure 3. Historical and recent flow at Wilkins Slough. Source: USGS.

Sites Reservoir —
Potential Benefits for Fish,
Potential to Worsen Conditions for Fish
Working Presumption: Thumbs Down

The proposed Sites Reservoir1 would be a new off-stream storage reservoir covering 12,000 -14,000 surface acres with 1.8 million acre-ft of storage capacity on the west side of the Sacramento Valley (Figure 1). The project would capture and store unregulated Sacramento River winter-spring runoff and some water previously stored in Shasta Reservoir. The diversion capacity to the reservoir would be 5400-6500 cfs, supplied by two existing river diversions (up to 1800 cfs at Red Bluff; up to 2100 cfs at Hamilton City) and a new diversion near Colusa (proponents are evaluating alternative capacities of 1500 and 3000 cfs, in addition to the currently preferred capacity of 2000 cfs). The Sites Authority webpage estimates that it could have diverted over 1 Million acre-ft to storage in Sites in 2018 and 1.8 Million acre-ft to storage in 2017; these figures assume bypass flow requirements at the diversion points and at Freeport, and sufficient storage capacity in the reservoir. The Draft Environmental Impact Report/Environmental Impact Statement (DEIR/DEIS) for the Sites Reservoir Project estimates the average annual diversion to Sites storage at about 500,000 acre-ft; actual diversions would vary depending on hydrology and regulatory constraints.

As an off-stream storage reservoir, Sites would store water behind a dam that is not on a major waterway. Water diverted to the reservoir would be pumped into canals from the Sacramento River, and then pumped into the storage reservoir from small holding reservoirs on the canals. The two existing diversions that would fill Sites have modern fish screening facilities. As currently envisioned, a pump-back hydroelectric operation would allow partial recovery of pumping costs.

The Sites project has potential benefits for fish, but also the potential to worsen conditions for fish.

Potential Benefits for Fish

  1. Under current operations, existing irrigation diversions on the Sacramento River draw water primarily in spring and summer via several major canal systems on the west side of the Sacramento Valley. These diversions draw mainly on water that was previously stored in Shasta Reservoir and released to the Sacramento River in part to keep river water temperatures cool. Shasta Reservoir’s cold-water pool varies in volume depending on storage and other factors, and can run out if it is not managed carefully. If the cold-water pool is depleted at the end of the summer, this threatens the viability of winter-run salmon. Under current operations, spring and summer irrigation diversions from the Sacramento River also cut flow and raise water temperatures in the lower river, which harms salmon, steelhead and sturgeon. Water diverted to storage in Sites in the winter could substitute for some of the spring and summer irrigation deliveries that currently come from Shasta. A greater percentage of water released from Shasta in spring and summer could then flow all the way to the Delta. More water could also be retained in Shasta Reservoir to protect the Shasta cold-water pool into the fall and as carryover for the following year.
  2. If more water were delivered to the Delta from Shasta Reservoir in the spring and summer, less water would theoretically be needed from Folsom and Oroville reservoirs to meet Delta water quality, outflow and other requirements. This could allow more targeted releases of water into the lower American and lower Feather rivers to protect fish in those waters. It could also allow better maintenance of cold-water pools and greater carryover storage in Folsom and Oroville, also very important for the respective fisheries downstream.
  3. Water stored in Sites could be delivered directly to the Delta via the Colusa Basin Drain (CBD) system and Yolo Bypass, reducing outflow demands from other Valley reservoirs. Water delivered directly to the Delta from Sites would be of higher potential productivity and could stimulate winter-spring Bay-Delta plankton blooms that would benefit Delta native fishes.

Potential to Worsen Conditions for Fish

  1. The proposal includes a new point of diversion on the Sacramento River with a capacity to divert 2000 cfs. This would give the project higher diversion capacity and the capability of diverting tributary runoff that would otherwise be unavailable to the two upper river diversions that now enters the Delta. This diversion would also affect flows and water temperatures in the lower Sacramento River, and subject migrating juvenile salmon, sturgeon, and steelhead to a third large screening facility. The new point of diversion would be particularly problematic if it diverted water outside the peak runoff season (late fall through spring).
  2. The new diversion and the reoperation of canal intakes at Red Bluff and Hamilton City to divert water in winter would compete for water with Delta diversions and would affect Delta outflow to the Bay.
  3. Water deliveries and hydropower releases from Sites Reservoir to the lower river at the new diversion site could affect water quality in the lower Sacramento River.
  4. With available winter off-stream storage, the existing diversions at Red Bluff and Hamilton City would be capable of diverting uncontrolled flows from tributaries that have otherwise remained relatively untouched down to the Delta.
  5. The greater diversion capacity may increase demands on Shasta storage and will increase diversion of uncontrolled tributary flows, further compromising fishes in the Sacramento River and the Bay-Delta.
  6. A small but potentially significant amount of water supply stored in Sites Reservoir would be lost to evaporation and groundwater seepage.

Above all, there is too much unknown to evaluate how Sites would affect fish.

As is the case for most proposed water supply projects, the project description in the draft DEIR/DEIS for Sites describes several potential configurations of project infrastructure and a description of proposed constraints. The DEIR/DEIS does not evaluate different constraints, such as different bypass flow requirements past each point of diversion; the DEIR/DEIS only evaluates one value for each point. In spite of numerous requests that the DEIR/DEIS evaluate project diversions with more stringent Delta flow and water quality requirements than the existing inadequate ones, the DEIR/DEIS only evaluates project yield with existing Delta constraints.

The benefit side is even more vague and conceptual. The entire construct of hypothetical Sites benefits would in fact require a new type of proscriptive rules and enforcement mechanisms that would be unprecedented for California water projects. There is simply no clue in any of the Sites literature what those rules would be or even could be.

The project description places no numbers on how much water stored in Sites the project’s operators would dedicate to actions designed to benefit fish. The project description defines no decision-making process for dedicating water to fish, other than to say that on an overarching basis fish agencies will decide. The project description defines no way in which project operators will apportion water for fish against water for water supply. For all the offsets that seem to comprise the lion’s share of fish benefits, the project description does not say how water from Sites will generate improvements in operation of state or federal reservoirs, or whether it will be Sites operators or state and federal operators who make the calls.

Then there is the question of whether there would be any offsets at all. There is no assurance that there will be any decreases at all in water use from Shasta or from other state and federal reservoirs. Water freed up by using Sites to meet Sacramento Valley water supply could simply allow Sac Valley water users to irrigate more land or sell more water for export at the Delta pumps. The DEIR/DEIS proposes no mechanism of enforcing offsets: who would regulate the project’s use of water, who would manage the interaction between Sites water and water from Shasta, Oroville, Folsom and perhaps Trinity reservoirs, and how and against whom any requirements would be enforced.

There are other problems. A shift to winter-spring diversions and use of canal systems would potentially change groundwater recharge and use patterns in the Sacramento Valley. The project would compete for water available to the proposed WaterFix Twin Tunnels project in the Delta. Sites and WaterFix have their “sights” on the heretofore untouched tributary inflows that are also protected by Delta export OMR limits so the flows reach the Bay. There will be a big fight over this uncontrolled water that now makes up a significant portion of the Bay’s freshwater input in drier years. Both projects have claimed future benefits of the same pot of water.


There are potential benefits from Sites project’s main features to Central Valley fishes, including salmon, steelhead, sturgeon, smelt, and striped bass. Most of the benefits would result from switching the diversion time period of the two existing upper river diversions and Shasta reservoir releases to these diversions. The added new diversion and increase in winter diversions will at important times reduce Sacramento River flow and Bay-Delta inflow and outflow, harming fish in certain but sometimes hard to quantify amounts.

Past water developments in the Central Valley have overwhelmingly made conditions for fish worse. The Sites project proponents claim that their project will be different. These proponents have not done themselves, the public, or public policy any favors by relying on generalities and politics as the centerpieces of their efforts to advance their project. At this time, there are too many unknowns to meaningfully evaluate the possibility that benefits might outweigh the harm and justify the costs. In the meantime, it is a reasonable working presumption that the Sites project will worsen conditions for fish as well.

Figure 1. Proposed Sites Reservoir and associated infrastructure on west side of the Sacramento Valley.

Spring 2018 – Unusual at Best

Flow conditions into and through the Delta are creating an unintended adaptive management experiment this spring. The San Joaquin River is providing half of the 20,000 cfs of Delta inflow. Exports and other water diversions are each taking about 3000 cfs from the Delta, leaving 14,000 cfs for outflow to the Bay. The Delta has been free of salt (Collinsville has been fresh at 200 EC, but salt is now encroaching). These are good conditions for the Delta and the San Joaquin, but horrendous for the Sacramento. Such conditions are highly unusual.

The Bureau of Reclamation’s decision to save water in Shasta reservoir, combined with a low water level in Oroville Reservoir because of ongoing repairs, have led to poor flows and high water temperatures in the lower Sacramento River. Flow at Wilkins Slough on the Sacramento River above Feather River confluence has fallen to 4000 cfs (Figure 1). Flow in the Sacramento River at Verona, below Feather River confluence, is only 7000 cfs (Figure 2). Water temperatures have reached 60°F at Red Bluff and 70°F at Wilkins Slough. Water temperatures above 56°F are detrimental to spawning winter-run salmon near Red Bluff. Water temperatures above 65°F are detrimental to out-migrating juvenile salmon, steelhead, and sturgeon.

A recent increase in releases from Shasta Reservoir is accommodating agricultural diversion demand in the upper Sacramento River below Shasta (Figure 3), while flows decline in the lower river. The increase in the upper river has stimulated emigration of wild juvenile salmon from the upper river, as shown by increased catch at the Red Bluff screw traps (Figure 4). The problem is that two-thirds of river flow is being diverted for Sacramento Valley agriculture, and river temperature rises 10°F along the way. Sacramento River salmon that reach the Delta, along with other Central Valley wild and hatchery salmon, are subject to south Delta exports (Figures 5 and 6). Though south Delta exports have been reduced, their effect remains significant because of low Sacramento River inflow to the Delta.

As I have suggested in past posts, Shasta Reservoir releases should be increased or water diversions from the upper Sacramento River reduced by several thousand cfs, in order to increase lower river flows and reduce water temperatures to no higher than the state water quality standard of 68°F. If this action is not taken, we will simply be feeding most of the young salmon to the abundant stripers that thrive in warm water conditions between Redding and the Bay (Figure 7).

Figure 1. Sacramento River flow at Wilkins Slough in spring 2018.

Figure 2. Sacramento River flow at Verona in spring 2018.

Figure 3. Sacramento River flow below Shasta/Keswick dams in spring 2018.

Figure 4. Catch of juvenile salmon in screw traps, water temperature, river flow, and turbidity near Red Bluff in Sacramento River.

Figure 5. Juvenile Chinook salmon salvage at south Delta export facilities in spring 2018. Red circle outlines recent salvage of wild juvenile spring- and fall-run smolts.

Figure 6. Juvenile Chinook salmon salvage at south Delta export facilities in spring 2018.

Figure 7. Striper limits from late April 2018 guide trip on lower Sacramento River. Source: James Stone.

Sacramento River Salmon and Water Right Order 90-5

Operation of the Central Valley Project’s Shasta-Trinity Division is governed in part by the State Water Board’s Water Right Order (WRO) 90-5. Issued in 1990, this Order prescribes reasonable protection for Sacramento River salmon, steelhead, and sturgeon even under today’s conditions. The problem in recent years is that “requirements” are not being met by the Bureau of Reclamation.

Even in the past three non-drought years, including record wet 2017 and this year’s normal classification, Reclamation has not met requirements. This has caused significant impacts to salmon, steelhead, and sturgeon, which I have documented in prior posts. In the past three years, Reclamation has used its poor performance during the 2013-2015 drought and global warming as excuses to prioritize preserving water storage in Lake Shasta over meeting water temperature requirements for the Sacramento River under WRO 90-5. But while Reclamation has argued it must preserve Shasta Reservoir’s cold-water pool, Reclamation has maintained full deliveries to its Sacramento Valley contractors.

The State Board has a whole website dealing with the issue and problems dealing with Reclamation on the issue: (https://www.waterboards.ca.gov/waterrights/water_issues/programs/drought/sacramento_river/ ).

In a March 14, 2018 letter to Reclamation, the State Board’s Deputy Director for Water Rights wrote to Reclamation on compliance with WRO 90-5,1 stating:

As you know, Order 90-5 requires Reclamation to maintain a daily average temperature (DAT) of 56 degrees Fahrenheit (F) in the Sacramento River at Red Bluff Diversion Dam during times when higher temperatures will be detrimental to fish, unless factors beyond Reclamation’s reasonable control prevent it from maintaining such temperatures. If Reclamation is unable to meet the temperature requirement at Red Bluff Diversion Dam throughout the temperature control season, Reclamation must develop an operations plan for approval by the Chief of the State Water Board’s Division of Water Rights (Deputy Director). The plan, which is required to be developed in consultation with the California Department of Fish and Wildlife, U.S. Fish and Wildlife Service, National Marine Fisheries Service (NMFS) (collectively fisheries agencies), and the U.S. Western Area Power Administration (WAPA), must designate a location upstream of Red Bluff Diversion Dam where the temperature requirement will be met. Order 90-5 includes specific monitoring and reporting requirements in addition to a general requirement (Condition 3) that Reclamation conduct such monitoring and reporting as is required by the Deputy Director to ensure compliance with the terms and conditions of Order 90-5.

Given potential concerns with temperature management this year and the degraded status of the winter-run Chinook salmon population following the drought, Reclamation should be aware that operational changes may be needed beyond those proposed by Reclamation in their TMP to minimize impacts to winter-run Chinook salmon and avoid redirected impacts to other native species. Reclamation should acknowledge those needs in its TMP and provide for a process for continually evaluating conditions and operations to ensure that needed adjustments to temperature control operations are considered in a timely manner.

On April 2, 2018, Reclamation responded2:

This response not only states that Reclamation will not meet WRO 90-5 water temperature requirements at Red Bluff (river mile 243), but also that it will not meet these requirements at Balls Ferry (river mile 276), 30 miles upstream and half way to Keswick Dam. In fact, Reclamation to date has blatantly kept the promise of not meeting requirements (Figure 1), despite the fact that Shasta Reservoir is full of cold water. It is not even May yet!

The Coleman Fish Hatchery just stocked 4 million fall-run salmon hatchery smolts at Battle Creek upstream of Red Bluff, with another 2 million soon to follow.3 The recently released hatchery fish (and their wild counterparts) are being subjected to highly stressful conditions in their 200-mile journey to San Francisco Bay (Figures 2 and 3).

There is plenty of cold water in Shasta Reservoir (Figures 4 and 5) to meet the flow and temperature needs of salmon in the lower Sacramento River through the summer, as required by WRO 90-5. It would take a total release of about 6000 cfs from Shasta to meet WRO 90-5 requirements at this time just at Balls Ferry. Reclamation increased releases in the past several days to 5300 cfs to meet water contractor demands. The problem remains that this water is not reaching the lower river, where water temperatures now hit 70°F and exceed the WRO 90-5 limits of 68°F (Figure 3). It will take an added 2000-3000 cfs at Wilkins Slough to keep the lower river below its 68°F limit This added release would represent about one foot of Shasta Reservoir water-surface elevation per week (Figure 4).

Sacramento Valley contractors have been given a 100% water allocation. South of Delta San Joaquin CVP contractors have been allocated only 40%. Reclamation is fully capable of meeting WRO 90-5 requirements, as it did historically. It is up to the State Board to enforce the CVP permit requirements. Given the state of the salmon populations, there should be no compromise on the permit requirements.

Figure 1. Reclamation report on Sacramento River temperatures through 24 April, 2018. Source: https://www.usbr.gov/mp/cvo/vungvari/sactemprpt.pdf

Figure 2. Water temperature at Red Bluff (RM 243), April 2018. Red line is limit requirement in WRO 90-5. Source: cdec.

Figure 3. Water temperature at Wilkins Slough (RM 118) April 2018. WRO 90-5 limit is 68°F. Water temperatures in excess of 65°F are highly stressful to juvenile salmon. Source: cdec.

Figure 4. Shasta storage characterization for water at the dam’s temperature control device (TCD), March 23 – April 22, 2018. Source: https://www.usbr.gov/mp/cvo/vungvari/ShastaTCD2018.pdf (See link for updates.)

Figure 5. Shasta Reservoir storage as of April 24, 2018.
Source: http://cdec.water.ca.gov/resapp/ResDetail?resid=SHA

  1. https://www.waterboards.ca.gov/waterrights/water_issues/programs/drought/sacramento_river/docs/2018/03142018_sac_temp_plan_ltr.pdf
  2. https://www.waterboards.ca.gov/waterrights/water_issues/programs/drought/sacramento_river/docs/2018/04022018response_90_5.pdf
  3. Note that Coleman Fish Hatchery on Battle Creek normally stocks 12 million fall-run smolts, but brood year 2014 salmon did not provide sufficient spawners (eggs for hatchery), and the hatchery thus produced only 6 million smolts in 2017. Hopefully, the 2 million smolts that have not yet been released will be trucked to the Bay.