Category Archives: Sturgeon

Protecting Salmon and Sturgeon May-June 2017

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Despite a record water supply in 2017, water operations in the Sacramento Valley are already threatening salmon and sturgeon because water managers are not meeting flow and water temperature targets and regulators are not enforcing them.

The water temperature of the Sacramento River at Red Bluff (river mile 240) exceeds the target of 56oF in the Salmon Biological Opinion, water right permits, and Basin Plan (Figure 1a).  The water temperature at Red Bluff (Figure 1a) is also approaching the 60oF tolerance limit for salmon and sturgeon eggs and embryos.  The water temperature in the lower Sacramento River at Wilkins Slough (river mile 125) exceeds the 65oF tolerance limit for sturgeon larvae and approaches the 68oF Basin Plan tolerance limit for migrating juvenile and adult salmon and sturgeon (Figure 1b).  To protect migrating salmon and sturgeon, water managers need to maintain a flow in the lower Sacramento River of at least 10,000 cfs through the summer of this very wet year (Figure 2).

Figure 1. Sacramento River water temperature at (a) Red Bluff (river mile 240) and (b) Wilkins Slough (river mile 125) during May 2017. Red lines depict Basin Plan targets. Source: CDEC.

Figure 2. Mean daily river flow in the lower Sacramento River at Wilkins Slough (river mile 125) during May 2017. Source: USGS.

Green Sturgeon Status – late summer 2016

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Young green sturgeon captured in Red Bluff trap. This specimen is quite large as most of the green sturgeon caught in the screw traps in late spring and early summer average one inch in length. Source .

Young green sturgeon captured in Red Bluff trap. This specimen is quite large as most of the green sturgeon caught in the screw traps in late spring and early summer average one inch in length. Source1 .

In an August 15, 2016 post on its Pacific Southwest Region website, the US Fish and Wildlife Service observed that the numbers of young green sturgeon have gone up this year in trap collections below the Red Bluff Diversion Dam.2 The article notes that this could represent an increase in the population. Joe Heublein, NMFS’s Green Sturgeon Recovery Coordinator, is also cautiously optimistic, according to the article.

Since 2012, gates at the Red Bluff dam have not hindered adult sturgeon from moving upstream past the dam to reach spawning grounds. Since 2016 was the first non-drought year since 2012, it seems likely that there should be an increase in the capture of recently spawned juveniles migrating downstream past the dam.

Missing from the story, however, is the fact that these juvenile sturgeon faced a particularly tough journey between Red Bluff and the Bay this summer, as discussed in my previous post on green sturgeon. Low flows and high water temperatures were a serious problem for the young sturgeon in the lower reaches of the Sacramento River in 2016. Unless their downstream rearing and migratory habitat is improved, the green and white sturgeon populations will have a bleak future.

The presence of young is a good sign. The species is long-lived, and thus it is not too late to recover this state and federally listed endangered fish. Getting rid of the Red Bluff diversion Dam five years ago was a big first step. The focus now should be on late spring through summer Lower Sacramento River habitat.

Since the beginning of summer 2016, conditions have improved (Charts 1 and 2). In August, flows at Wilkins Slough increased to 5000-7000 cfs, and water temperatures were down near 70°F. In late May and June, water temperatures at Red Bluff (Chart 3) were near lethal (68°F) for the really small fish, and were most likely worse not far downstream (Chart 2). Now temperatures are closer to the Basin Plan’s prescribed 56°F at Red Bluff and 68°F at Wilkins Slough.

The initial problem this year was the result of reduced releases from Shasta Reservoir to save its cold water pool for winter-run salmon, combined with normal agricultural water allocations in the Sacramento Valley. Recent improvements are the result of the normal late summer reductions in irrigation demands. In the future, Basin Plan objectives should be met by a reduction in Sacramento Valley water allocations when water is not sufficient to allow higher overall summer reservoir releases from Shasta.

Chart 1. River flow at Wilkins Slough (RM 125) late spring through summer 2016.

Chart 1. River flow at Wilkins Slough (RM 125) late spring through summer 2016.

Chart 2. Water temperature at Wilkins Slough (RM 125) late spring summer 2016.

Chart 2. Water temperature at Wilkins Slough (RM 125) late spring summer 2016.

Chart 3. Water temperature in Sacramento River at Red Bluff from late spring through summer 2016.

Chart 3. Water temperature in Sacramento River at Red Bluff from late spring through summer 2016.

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.

State Board: Increase Sacramento River Flow

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The State Water Resources Control Board is responsible for enforcing water rights and the Sacramento River Basin Plan that protects beneficial uses including fish and water quality.1 The Basin Plan’s 68°F objective for the lower Sacramento River is clearly being violated right now because of low Sacramento River flows brought about by lower than normal Shasta releases and a 100 % allocation of water to Sacramento Valley water contractors. The State Board has jurisdiction over both of these factors through control of water rights. The State Board is about to review Reclamation’s Water Temperature Plan (WTP) for summer 2016, which calls for a 10,500 cfs release in July, several thousand cfs below normal, to conserve Shasta’s cold-water pool for salmon through the summer and fall. The WTP however has no provisions for cutting downstream water use. Thus, flows in the lower Sacramento River will be lower, with higher water temperatures that violate the Basin Plan. The flows must be raised at Wilkins Slough (RM 125) by either increasing Shasta releases or reducing water diversions, or a combination thereof.

The Basin Plan objective of 68°F is there to protect salmon and sturgeon migrating and rearing in the lower Sacramento River. Water temperatures above 68°F are stressful to the fish, affecting growth, survival, and subsequent reproduction. Present water temperatures in the lower river (Figure 1), caused in part by low flow (Figure 2), are lethal to salmon and sturgeon. In 2010 and 2012, water years similar to 2016, flows were higher and water temperatures were lower in early summer (Figures 3-6).

The State Board, in reviewing the WTP, must explicitly consider flows and water temperatures in the lower Sacramento River under its broader responsibilities to protect fish as prescribed in the Basin Plan and in various water rights orders.

Figure 1. Water temperature of lower Sacramento River at Wilkins Slough (RM 125) in early summer 2016.


Figure 1. Water temperature of lower Sacramento River at Wilkins Slough (RM 125) in early summer 2016.

Figure 2. Sacramento River flow at Wilkins Slough (RM 125) in early summer 2016.

Figure 2. Sacramento River flow at Wilkins Slough (RM 125) in early summer 2016.

Figure 3. Water temperature of lower Sacramento River at Wilkins Slough (RM 125) in early summer 2010.

Figure 3. Water temperature of lower Sacramento River at Wilkins Slough (RM 125) in early summer 2010.

Figure 4. Sacramento River flow at Wilkins Slough (RM 125) in early summer 2010.

Figure 4. Sacramento River flow at Wilkins Slough (RM 125) in early summer 2010.

Figure 5. Water temperature of lower Sacramento River at Wilkins Slough (RM 125) in early summer 2012.

Figure 5. Water temperature of lower Sacramento River at Wilkins Slough (RM 125) in early summer 2012.

Figure 6. Sacramento River flow at Wilkins Slough (RM 125) in early summer 2012.

Figure 6. Sacramento River flow at Wilkins Slough (RM 125) in early summer 2012.

June Update and Possible Solution to 2016 Fish Woes

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Over the past month I related water issues involving Delta and longfin smelt, striped bass, green and white sturgeon, and winter-run and spring-run salmon. All of these species need river flow and cooler water over the next several months. Shasta releases to the upper Sacramento River need to be cold, stable, and sufficient to sustain winter-run salmon eggs in the river near Redding and to sustain moderate flows and cooler water temperatures for 200 miles of river to protect sturgeon and other lifestages of salmon. Sufficient flows needs to pass through the Delta to keep the low salinity zone downstream of the Delta in the cool waters of eastern Suisun Bay, away from Delta exports.

Shasta releases are now 8000 cfs, with Bend Bridge water temperature near the Red Bluff target of 56°F. In June and July of drought years 2012 and 2013, releases were 11,000-14,000 cfs. However, concern over carryover storage and sustaining cold-water releases through summer has led to a more conservative management strategy in 2016. The cold-water pool in Shasta Reservoir is being rationed to make it through the summer. Flows will rise over the next six weeks to 9,000 or 10,000 cfs to satisfy irrigation demands in the upper river.

Flows in the lower Sacramento River at Wilkins Slough need to be greater than 5000 cfs in summer, if only to keep water temperature down closer to the Basin Plan’s 68°F. Flows are now 3000-4000 cfs, with water temperatures up to 75°F. In dry years 2012 and 2013, flows at Wilkins Slough were 6000-9000 cfs, and water temperatures were cooler, as some of Shasta’s storage was allocated for Delta export. This year’s management strategy to hold back Shasta releases will, if continued, keep both Wilkins Slough flows and Delta exports down.

Delta outflows need to be sustained near 10,000 cfs to keep the low salinity zone and X2 (2 ppt salinity) near Collinsville in eastern Suisun Bay. However, July outflow to the Bay required by water quality standards will be only about 8000 cfs. To help save the last of the two smelt species, 10,000 cfs would be far better.

A reasonable solution is apparent: raise Shasta releases through most of the summer by 2000 cfs to 10,000-12,000 cfs and require that the extra release be passed down the river to and through the Delta. While such a management strategy would benefit the fish, it would decrease Shasta storage by 120,000 acre-ft of water per month. At present, Shasta is 90% full at 4.1 million acre-feet (the cold-water pool volume is about 2.4 maf). At 12,000 cfs, the total Shasta release would rise to 600,000 acre-feet per month, which is about the current total release from Oroville (Feather River) and Folsom (American River) reservoirs. NMFS and USBR have determined that a 10,000 cfs Shasta cold-water release can be sustained through the summer, while a 12,000 cfs release could be problematic. Protests would no doubt come from water users who would want the extra 2000 cfs. But note that of the 20,000 cfs being released today from the three main Sacramento Valley reservoirs, only 8000 cfs is reaching the Bay.1

This solution of raising total reservoir releases to 22,000-24,000 and Bay outflow to 10,000 cfs is reasonable to help the fish after four years of drought. In 2014-2015, water quality standards were drastically reduced, with catastrophic effects to fish. The continuing legacy of these catastrophic effects creates the urgency to do better in 2016.

If higher releases from Shasta become problematic for whatever reason, then some compromise should be achievable, noting that water deliveries of Shasta water are to be provided only after the needs of the fish are first considered, including conservation of Shasta’s cold-water pool through the summer and early fall (Water Rights Orders 90-05 and 92-02). Further, Central Valley water rights are provided via the Trinity River trans-basin diversion to Keswick Reservoir on the Sacramento River below Shasta Dam, but the Trinity supply is much in doubt because Trinity storage has failed to recover after the drought, unlike Shasta storage. A lack of Trinity supply this summer will further limit water available for irrigation in the Central Valley. Yet another constraint is whether the available storage in Oroville and Folsom reservoirs is able to satisfy Delta demands without compromising the needs of endangered fish in the Feather and American rivers.

Sorting out these conflicts and needs is the responsibility of the State Water Resources Control Board. The Board’s top priority should be the basic needs of the endangered salmon, sturgeon, and smelts of the Central Valley. At minimum, the Board should require the following conditions this summer:

  1. Below Shasta – Stable flows of 9,000 to 10,000 cfs and 56°F average daily water temperatures near Red Bluff (Jellys Ferry or Bend Bridge).
  2. Lower Sacramento River – minimum 5000 cfs at Wilkins Slough (RM 125 on the Sacramento River)
  3. Delta Outflow – 9,000 cfs in July, 5,000 cfs in August, and 4,000 cfs in September.
  1.  A further complication is that South Delta export criteria allow an increase from 35% of inflow to 65% starting July 1.  Exports in June are limited to 5000 cfs.  In July, exports can be raised to 65% of inflow, but only if outflow is kept at 8000 cfs.  Delta ag diversions are also near 4000 cfs.  Thus July Delta inflow of  20,000 cfs or more (compared to the present inflow of 15,000 cfs) would be needed to allow 10,000 cfs of Delta export.   ↩