Category Archives: Bay-Delta

Predation

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“While state and federal wildlife agencies, university researchers, and water users all agree that predation from non-native fishes is a major stressor on salmon populations, we have done nothing to try to directly curb its impact.”

This statement in a recent Fishbio blog post is simply not true.

In 1995, the state removed limits on summer Delta exports that had been in place for decades to protect young striped bass. Stocking of striped bass ended at the beginning of this century. Both actions contributed to record low production of striped bass over the past decade. 1 The Bay-Delta population of striped bass is now greatly depressed. The river population is sustained by the continuing policy of releasing hatchery salmon smolts in the spring at the hatcheries, an unnatural process that simply feeds the river stripers.2

The real problem is spring water management in the Sacramento and San Joaquin rivers that brings unnaturally low flows and warm, clear water that favors the predators. All the salmon runs naturally have juveniles migrating to the Bay in high cold flows from late fall to early spring when predators are inactive and ineffective. But with dams holding the water from winter rains and snows, the rivers lack natural winter flows and spring snowmelt.

Largemouth bass production in the Delta has increased because of habitat changes from water management, droughts, and invasive aquatic plants that have turned the Delta into an “Arkansas lake.” Smallmouth bass production has increased in the rivers with lower, warmer flow conditions from spring through fall.3

The native pikeminnow also benefit from the habitat changes in the rivers and Delta, as well as the abundance of spring hatchery smolts. Huge schools migrate from the Delta into the rivers in spring and summer to spawn. The tailwaters downstream of dams favor pikeminnow. The adults feed on young salmonids and the juveniles compete with juvenile salmonids. Juvenile pikeminnow that return to the Delta feed on smelt.

It is these habitat changes that have resulted in more effective predation on native salmon, steelhead, and smelts. Ignoring the cause won’t solve the problem. Focusing on the predators will not work. The basses and native pikeminnow have prolific reproductive systems. Killing more of them by removing regulations on their harvest or even putting bounties on them (like pikeminnow on the Columbia River) will not solve the root problem – habitat change. And without the predators, what would be left to control all the non-native forage and “trash-fish” that already plague the Delta and rivers?

In the future, if we continue to take more of the river flows and further degrade habitats, there will always be the temptation and the drumbeat to directly remove predators or inhibit their migrations. We can stop salvaging millions of these predators every year at the South Delta export facilities, stop returning all the bass caught in fishing tournaments, and truck all the remaining salmon produced only in hatcheries to the Bay. In the end we will still have abundant predators, an “Arkansas-like lake,” hatchery salmon, and at best novelty populations of endangered wild salmon, steelhead, sturgeon, smelts, complemented by likely newly listed species of native fishes like splittail, blackfish, hitch, etc.

Smallmouth Bass Expansion (Hypothesized)

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One of the major salmon predators on the Columbia River is the smallmouth bass. Long protected because of its contribution to a highly popular sport fishery, that protection is now gone because of the predation threat to Columbia River salmon recovery. Smallmouth and walleye are highly regarded game fish, but are not native to the Columbia River. They compete with and prey upon salmon. The Columbia states recognized this and no longer regulate these fisheries. This change will help prevent expansion of these species as global warming provides more favorable conditions for these cool-water non-natives than for the cold-water salmon, sturgeon, and steelhead.

Smallmouth bass have long been present in the Central Valley, especially in the lower Sacramento River and the rim dam reservoirs. Recent changes in the management of water in the lower Sacramento River will accelerate expansion of smallmouth and their preferred habitats over that of global warming alone. Smallmouth have historically been constrained by Basin Plan’s 56°F water temperature limit at Hamilton City (or Red Bluff) and the 68°F limit below Hamilton City to the Delta. However, smallmouth are highly likely to expand their population and range in the lower Sacramento River due to recent changes in flow management strategies that provide lower flows, warmer waters, and less turbidity to nearly 200 miles of the lower Sacramento River.

Ironically, the strategy changes meant to save water and cold-water reservoir supplies for salmon will actually benefit smallmouth, a key predator on salmon. The changes have already benefitted striped bass by enhancing their opportunities for predation. 1 An expansion of the smallmouth population is now likely because of warmer spring water temperatures (Figures 1 and 2) caused by lower river flows in the spring (Figure 3). The more days water temperatures exceed 60°F, the more successful spring breeding and survival of smallmouth will be. 2

Removing fishery protections will not solve the potential population enhancement or predation problems of smallmouth in the Central Valley. It would be a purely symbolic measure because smallmouth are so abundant and widely distributed. It is limitations on their habitat that have held back their expansion and the impact of their predation on salmonids. With the habitat limitations lessening, the smallmouth population will expand and contribute more to the predation problem. The solution is to restore former habitat limitation on smallmouth by sticking to the Basin Plan standards.

For more on smallmouth life history see this excellent YouTube video: https://www.youtube.com/watch?v=hoZ81au_YZg. Note in the video the strategy of smallmouth feeding heavily in the fall on small fish to store energy for the coming winter. Fall is when the winter-run salmon juveniles produced over the summer start their 200-mile downstream journey from the upper river spawning grounds to the Bay. All 200 miles have smallmouth bass.

Figure 1. Water temperature in Sacramento River at Red Bluff (RM 243) in spring 2016. Red line depicts Basin Plan limit of 56°F for river at Red Bluff.

Figure 1. Water temperature in Sacramento River at Red Bluff (RM 243) in spring 2016. Red line depicts Basin Plan limit of 56°F for river at Red Bluff.

Figure 2. Water temperature in Sacramento River at Wilkins Slough (RM 125) in spring 2016. Red line depicts Basin Plan limit of 68°F for lower river.

Figure 2. Water temperature in Sacramento River at Wilkins Slough (RM 125) in spring 2016. Red line depicts Basin Plan limit of 68°F for lower river.

Figure 3. Sacramento River daily flow for years 2008 to June 2016. Red line depicts normal flow of 5000 cfs. Circles depict the tendencies for lower flows in recent years including spring 2016.

Figure 3. Sacramento River daily flow for years 2008 to June 2016. Red line depicts normal flow of 5000 cfs. Circles depict the tendencies for lower flows in recent years including spring 2016.

My comments on: “SLDMWA Response to Environmentalists’ August 9, 2016 Request to the SWRCB for Even More Water Aimed at Protecting Delta Smelt”

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On August 11, Jason Peltier, executive director of the San Luis-Delta Mendota Water Authority, offered comments on a letter from environmental groups to the State Board that requested more water for Delta Smelt. Below, I provide some of Mr. Peltier’s statements, and a response to each:

1. “As environmental special interests request the State Water Resources Control Board expand failed policies on Delta Smelt, Californians are calling on the Board to implement new science-based, common sense approaches to protect the species. It is disheartening to see once credible environmental organizations calling for a “more of the same” approach – one that has so miserably failed for a quarter century – in a misguided attempt to help the imperiled delta smelt.”


Comment: The environmental organizations were proposing what the state has also offered as its new strategy for the Delta Smelt. It is not the old misguided “failed” strategy of diverting more and more water and providing less and less Delta outflow to the Bay. The state’s new strategy derives from some of the same actions suggested in this past April’s science workshop on Delta Smelt held at UC Davis, which Mr. Peltier attended.

2. “[t]he Projects have compensated for Mother Nature’s stinginess with water released from reservoirs, making the Delta far fresher than it would have been naturally.”

Fact: Just the “natural” summer inflow to Shasta Reservoir in the past four years of drought nearly equaled the amount allocated for summer Delta outflow. If you add up all the Central Valley’s “natural” inflow it would far exceed the Delta outflow allotted, even without accounting for use above the rim reservoirs.

3. “This dedication of water for fish from what was stored for drought relief has resulted in unprecedented socio-economic and environmental harms to towns, farms, and numerous species living in the largest wetlands in the West.”

Fact: Most of the water stored is for agriculture and released for agriculture. Mr. Peltier’s organization is simply last in line for stored water and thus gets less water allocated during droughts. In June and July, nearly 30,000 cfs of water was released on average from Central Valley reservoirs, but only 7000-8000 cfs reached the Bay to repel salt intrusion. Because Shasta releases were reduced to protect salmon (not smelt), Mr. Peltier’s organization was unable to receive more than a minimal allocation. Again, this is because its water rights are junior to those of other users, not because of water allocated to smelt (none).

4. “Since the most severe cuts were imposed on the Projects nine years ago, less water has been diverted, and thus more Projects’ water has gone out to the ocean, than at any other time in the past 35 years.”

Fact: Seven of the last nine years were drought years. The only water consistently reaching the ocean in large amounts during those seven years was uncontrolled river flows and reservoir spills during and after sporadic winter storms. The only reservoir water that reached the ocean (Bay) in those seven dry years was the water necessary to hold back salt intrusion into the Delta so Delta diversions and exports remained possible.

5. “Farmers, fishermen, and environmentalists – everyone that truly cares about the status of our imperiled fisheries – should be furious.”

Comment: The fishermen and environmentalists are “furious” because of government mismanagement of the Shasta Reservoir cold water pool that has nearly wiped out the Sacramento salmon runs, and because of the weakening of Delta water quality standards in 2014 and 2015 that allowed excess salt into the Delta and just about exterminated the Delta smelt population.

6. “Decades old state and federal policies have failed and brought delta smelt and salmon to the brink of extinction. The last thing we need is more of the same.”

Comment: Yes, decades-old policies of increasing exports from the Delta has brought near-extinctions. It started with the massive State Water Project that came on line in the 1970’s. Yes, the last thing we need is “more of the same” – increasing exports promised with the WaterFix.

7. “Like delta smelt, we need shelter, we need food, and we need safety from predators, toxics, and invasion. The state and federal regulatory agencies have ignored for far too long the full needs of delta smelt, only willing to do what is easy, and we have all suffered for it.”

Fact: Delta smelt need the cool, brackish, wind-blown turbid waters of Suisun Bay provided when Delta outflow is sufficient to keep the low salinity zone out of the warm, confined channels of the Delta and away from its massive export pumps.

8. “We can continue to ignore decades of sound scientific advice, or we can embark on a bold new initiative, one that is transparent and inclusive of stakeholders working with state and federal agencies to save delta smelt.”

Comment: We have ignored the scientific advice. It has always been there. What “bold new initiative?”

9. “Now is not the time for desperate action, it is the time for thoughtful action.”

Fact: Giving the Delta Smelt 1000 or 2000 cfs in June and July this year – instead of nothing (Delta outflow was allocated to repel salt) – would entail only 3-6% of the water released from reservoirs and 5-10% of Delta inflow. After all, the Delta Reform Act of 2009 mandates that the state must implement the “co-equal” goals of providing a reliable water supply and protecting, restoring and enhancing the Delta ecosystem.

Low San Luis Reservoir

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Tim Quinn, Executive Director of the Association of California Water Agencies (ACWA), is trying again, as in so many of his blog posts, to hornswoggle us into believing that many of this year’s water woes have been caused by “overzealous” fish protections.1 His August 17, 2016 post on the Association of California Water Agencies (ACWA) website is focused on why San Luis Reservoir in the San Joaquin Valley has such low water storage this summer. San Luis storage went from 50% of capacity at 1 million acre-feet (MAF) at the beginning of April to 0.2 MAF (10% of capacity) at the beginning of August. All to human use.

Mr. Quinn correctly points out that lack of federal Delta exports to San Luis was due to a concerted effort by the Bureau of Reclamation to conserve Shasta Reservoir’s storage and cold-water pool to save this year’s spawn of winter-run salmon in the Sacramento River below Shasta. In 2016, federal and state agencies were gravely concerned about protecting this year’s spawn of winter-run salmon below Shasta. The past two years’ spawns had been wiped out after Shasta ran out of cold water. So after Shasta filled and spilled in late March, releases to the Sacramento River were limited to retain Shasta’s cold-water pool to sustain salmon through the summer (Figure 1). Releases (Shasta reservoir outflow) from the first of April through the end of July were about 700,000 acre-feet less than normal, saving reservoir storage and the cold-water pool. Instead of falling to 2.9 (MAF) of storage (64% of capacity) at the end of July as would more typically have been the case, Shasta was drawn down only to about 3.6 MAF (80% of capacity).

Figure 1. Sacramento River flow below Shasta/Keswick reservoirs near Redding. Red lines depict normal-release-pattern river flows at Redding.

Figure 1. Sacramento River flow below Shasta/Keswick reservoirs near Redding. Red lines depict normal-release-pattern river flows at Redding.

But there is more to the story. Sacramento Valley water contractors still took their normal allotments from the reduced Sacramento River supply, leaving little for San Luis. State Water Project contractors exported near the maximum from their Delta diversion facilities at Clifton Court this summer, using Oroville Reservoir water, while federal exports were less than 50%. Federal Folsom Reservoir water was used for Delta outflow requirements so that State Water Project exports could be accomplished (the feds owed the state water from 2015). Folsom, which started the year nearly full at 850 TAF, is now only at 40% of capacity and has once again closed its marinas. Ironically, enough water has flowed from the Delta this summer to (State Water Contractor) Metropolitan Water District’s Diamond Valley Reservoir in southern California to allow the Met to open its Diamond Valley marinas.

Just to be equitable, Mr. Quinn doesn’t blame only the salmon. He also blames the San Luis problem on the fact that “federal officials over-cautiously kept [Delta] pumping levels very low to protect Delta smelt” during winter storm pulses (Figure 2). He correctly states that restrictions on the federal and state water projects in the biological opinion for Delta smelt kept winter exports from the Delta at 20-70% of capacity. But again, where’s the context? Project operation in 2014 and 2015 just about obliterated the last remnant Delta smelt, and the some of the few pesky smelt that survived were indeed found to be spawning in the central Delta, not far from the export pumps, during the winter. Before we throw around adverbs like “over-cautiously,” perhaps we should balance with “recklessly” when we talk about what happened to bring us to a situation that demands such caution.

Figure 2. Storm pulses in the last five years from the Sacramento River into the Delta.

Figure 2. Storm pulses in the last five years from the Sacramento River into the Delta.

Mr. Quinn further states:

This scenario underscores the peril of regulatory agencies focusing almost exclusively on species protection at the expense of water supply. Moreover, efforts to protect endangered fish virtually always narrowly focus on a single element – temperature control or flows – while failing to address other important factors affecting the species. Allowing a single-stressor approach to drive water management decisions only serves to maximize conflict between species protection and water supply, while failing to adequately serve either. And we continue to lose water supply every day as a result.

Well, the water is needed by all the fish species, including all six listed species. It is needed for habitat, water quality, and all ecosystem functions in the rivers, Delta, and Bay.

About half of the water that hits the watershed eventually does reach the Bay as Delta outflow in the drier years, primarily during infrequent winter storms (Figure 2). Much of the rest of the outflow is needed to repel saltwater intrusion into the Delta, so that the water in the state and federal canals is not too salty to export. Annual runoff to the Bay ranges from about 5 to 10 MAF in these drier years. The State Water Board’s staff has said that the estuary needs 75% of unimpaired runoff to be healthy.

During winter storm pulses in a year that follows a dry year sequence, about 60-80% of the water (immediate rain and later snowmelt) is captured in Mr. Quinn’s constituents’ Central Valley rim reservoirs for summer use. In 2015, it was even worse: approximately 50% of the inflow to the Delta from the Central Valley in 2015 occurred during two storm periods. Most of the inflow came from undammed streams and local runoff, while the major reservoirs were capturing 80-90% of their inflow.

The big storms carry the offspring of salmon, steelhead, and sturgeon to the Bay, and represent most of the Bay’s freshwater inflow for the year. With the reservoirs capturing most of the inflows in the really bad years like 2015 , the rivers downstream of the major reservoirs, streams like the Sacramento, Feather, America, Mokelumne, Stanislaus, Tuolumne, Merced, and San Joaquin, get little winter water for fish spawning, rearing, and migrations.

The flow in rivers, the Delta, and the Bay directly or indirectly controls or partially controls all the stressors affecting the listed species. Flow even controls the water districts’ favorite stressor, predation.

Now, Mr. Quinn and his colleagues want us to pay untold billions of dollars for the California “Waterfix,” so they can take more water, especially during the infrequent storms in dry year winters. In the two storm pulses in winter 2015, the WaterFix Tunnels could have been operating at near capacity for about 30 days to take an added approximately 500 TAF, or about 20% of the total from the two storm pulses of Delta outflow. Instead of half the Valley inflow reaching the Bay, only 40% would make it due to the new Tunnels.

Low Flows – Deadly Water Temperatures

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Low flows in the Sacramento River and Delta lead to deadly water temperatures for Central Valley salmon, steelhead, sturgeon, and smelt, including six state or federally listed endangered species. Water quality standards and operating requirements for the state and federal water projects should include new flow limits to protect fish.

Sacramento River

Salmon, steelhead, and sturgeon are subjected to deadly spring and summer water temperatures when lower Sacramento River flows fall below 5000 cfs as measured at Wilkins Slough (Figure 1). Low flows and high water temperatures lead to poor survival and increased predation, and block migrations of adult salmon.

Delta

Low flows through the lower Sacramento River channel in the Delta also lead to deadly water temperatures for salmon and smelt. When Delta inflow falls below 10,000 cfs, water temperatures become deadly for Delta Smelt (Figure 2) and salmon (Figure 3).

Figure 1. Daily average water temperature and river flow in the Sacramento River at Wilkins Slough (RM 125) 2007-2016. Water temperatures greater than 75°F are lethal to salmon and sturgeon, and block salmon migration. The water quality standard for the lower Sacramento River is a limit of 68°F. Temperatures above 68°F are stressful to salmon, sturgeon, and steelhead, and lead to increased risk of predation, lower survival, and poor reproductive success.

Figure 1. Daily average water temperature and river flow in the Sacramento River at Wilkins Slough (RM 125) 2007-2016. Water temperatures greater than 75°F are lethal to salmon and sturgeon, and block salmon migration. The water quality standard for the lower Sacramento River is a limit of 68°F. Temperatures above 68°F are stressful to salmon, sturgeon, and steelhead, and lead to increased risk of predation, lower survival, and poor reproductive success.

Figure 2. Daily average water temperature and river flow in lower Sacramento River near Freeport. Water temperatures greater than 73°F are lethal to smelt and block salmon migrations.

Figure 2. Daily average water temperature and river flow in lower Sacramento River near Freeport. Water temperatures greater than 73°F are lethal to smelt and block salmon migrations.

Figure 3. Daily average water temperature in the south Delta at Clifton Court 2009-2016. Water temperatures greater than 25°C (77°F) are lethal to salmon and smelt.

Figure 3. Daily average water temperature in the south Delta at Clifton Court 2009-2016. Water temperatures greater than 25°C (77°F) are lethal to salmon and smelt.