‘Science day’ flows at Delta Stewardship Council

By From page B7 | August 15, 2014

Delta Stewardship Council Chairman Randy Fiorini is fond is saying, “There is no silver bullet” when it comes to meeting the council’s co-equal goals of providing a more reliable water supply for California and protecting, restoring and enhancing the Delta ecosystem.

At the council’s meeting on July 25, representatives of two independent science panels confirmed the chair’s viewpoint.

The meeting was held at the Park Tower Plaza in Sacramento. All council members were present: Chairman Randy Fiorini, Vice Chairman Phil Isenberg, Gloria Gray, Patrick Johnston, Frank Demrell Jr., Larry Ruhstaller and Susan Tatayon.

The presentation covered a review of the scientific studies, reports and papers, mainly produced by various agencies and stakeholders, on the waters flowing into the Sacramento-San Joaquin Bay Delta and the waters flowing out into the San Francisco Bay. Two panels of independent scientists from different disciplines were engaged by the State Water Resources Control Board to help narrow areas of scientific disagreement and uncertainty over the flows necessary for a healthy Delta.

The current Delta outflow standards were adopted by the board in 1995. The panel’s report will be used by the board to help set flow objectives for the Delta as part of the board’s update of the 2006 Bay-Delta Water Quality Control Plan. Meeting the flow objectives is one of the requirements for consistency with the Council’s Delta Plan.

The panels held a two-day public workshop in February, where it heard about a number of wide-ranging topics besides flows. The panels’ reports were given to the board in early July.

Smelt update

At the council meeting on July 25, Sam Haradar, science program manager for the board, explained that the focus on Delta outflows review was on the primary indicators of the low salinity zone (LSZ), including measuring phytoplankton abundance and indicators of fish populations, particularly Delta smelt and longfin smelt. Phytoplankton, also called microalgae, are single-cell floating plants common to an area that drift with the currents. They provide a crucial source of food to many fish.

The focus of the interior Delta flows review was survival of juvenile salmon and smelt. Both panels paid attention to the interaction with related stressors.

Haradar introduced Les Grober, board assistant deputy director, division of water rights;

Denise Reed, chief scientist, Water Institute of the Gulf; and Kenneth Rose, professor of oceanography and coastal sciences, Louisiana State University.

Delta flows

Grober described the Delta as the “choke point” for considering water quality, beneficial uses and water rights. He said the foundation of the current requirements are contained in the board’s 2006 Water Right Decision 1641. Depending on the water-year type (wet, dry, moderate) and season, the flow requirements for fish and wildlife beneficial uses are based either on specific Delta outflow requirements or a water quality standard that specifies the position of “X2.” X2 marks the distance in kilometers from the Golden Gate Bridge to a point where the salts dissolved in the water measure 2 parts per 1,000 grams. In wet years, it is naturally more seaward. In dry years, saltwater incursion moves the mark upstream. X2 is the standard approach used to set flow standards for estuaries internationally.

In 2010 the board produced a report on flow criteria. It was a technical assessment that dealt only with flow and the operational requirements that provide fishery protection under existing conditions. The 2010 report stated, “The best available science suggests that current flows are insufficient to protect public trust resources.” Using high-end flows, Grober noted, has high economic and hydrological costs.

He said the multiple back-to-back dry years are giving everyone a chance to evaluate drought as part of long-term planning when freshwater supplies are scarce.

Reed spoke as the chair of a seven-member panel. She said that X2 was originally thought of in 1993. “We’ve been at this for two decades, and the system has changed,” she said. “A single indicator for a complex system like this is really unrealistic to expect. A suite of indicators, including X2, is probably a more reasonable approach.”

There is so much going on there is no definite cause and effect, she said. She cautioned: Beware of what data goes in. “It’s critical that quantitative analysis communicate uncertainties in recommended flow criteria to decision makers.”

Regarding the use of adaptive management, Reed described it as a “Catch-22” situation. “Decision-makers are hesitant to adopt costly policies in the absence of relatively convincing model predictions that indicate they will achieve the desired objectives. However, it is very difficult to improve model predictions without implementing these policies in the first place.”

The rate of learning about the effectiveness of alternate flow policies in the Delta will likely be very slow.” She recommended explicit adaptive management plans and realistic experimental designs.

There have been long-term changes in the Delta water system, she said. The water is less turbid, more clear, allowing more light to penetrate. There is more phytoplankton growth. There are algae blooms in the low salinity zone. There are higher concentrations of ammonium and nitrates.

“Beware of latching on too quickly to one specific attractive explanation. Think broadly,” she said.

The panel suggested: 1) build on improved hydrodynamic models toward a “Delta ecosystem model; 2) increase assessment of fish “condition,” including routine sampling; 3) identify dominant biomass pathways that support fish at different life history stages.

“This is very difficult,” she said. “There are no easy solutions.”

Isenberg noted the panel did not prioritize any recommendations. He inquired what six things are most important to add to X2. Reed suggested a better way to get at the answer is to specify management objectives.

Fiorini commented, “There are real issues on the non-ecosystem side.” Reed responded, “We face similar issues in Louisiana. We are moving freshwater areas and people are protesting in the streets. Science is not a tool. There are societal preferences and priorities.”

Kenneth Rose is the only person who served on both panels. He was the spokesperson for the six members who reviewed the scientific studies on the interior Delta inflows. The emphasis on the interior inflows presentation was on Delta smelt, salmon and steelhead.

Rose said the Bay Delta has a complex mix of interacting factors affecting native fish vital rates and spatial distribution. “It’s not a good idea to keep talking about flows,” he said. “Fish don’t care about the flows. They care about the components of flow. What fish perceive are pressure, gradients, salinity and velocity. Understanding fish cues and migratory patterns is improving.”

He emphasized that fish live in evolutionary times. They adapted to the Delta in the pre-history period. The interior flows have dramatically altered since then. Tides are still important. So are timing and volume of flows, availability of habitat and transport of sediments and nutrients. The interior Delta is still too much of a “black box” for native fish in terms of survival, he said.

Rose said he does not favor ranking stressors. “They are too interrelated and confounded.”

He said that predation is a problem for survival of the native fish, but how much it contributes to mortality is not quantified. He added that invasive species are more successful in establishing in the Delta during drought periods.

Flow measurements are regularly taken seasonally or at specific locations. The seasonal cycles have shifted. The panel recommends creating a hydrograph that depicts changes in the rate of flow over the entire year.

Rose said the use of adaptive management is limited in the Delta. The system is constrained by limitations to manipulate the system to see effects. Monitoring is often not sufficient. It is expensive and the system is complicated.

Overall, he said, there is a lot of good science and historical data. He said that one of the problems in synthesizing progressive studies is that sometimes important information gets lost.

He mentioned another problem is the level of distrust in the scientific and stakeholder communities. “It’s a people problem,” he said.

In answer to questions from the council about what scientific studies to depend on, Rose suggested looking at the ones cited in the panel’s report.

In answer to the issue of distrust, Rose mentioned bringing in outside people, young people and more universities to create a turnover of ideas. There needs to be a reasonable expectation of benefit, he said.

Grober added that in balancing the competing uses of water, the process needs to be transparent.

Salinity effects on agriculture

John Herrick, counsel and manager for the South Delta Water Agency, represented the four members of a board panel on managing Delta salinity in a time of drought. The South Delta Water Agency is statutorily charged with protecting the quantity and quality of water in the southern Delta.

Salinity is a measure of the amount of salts in water. It can have different components. In water, salt breaks into positive and negative ions that conduct electricity. Conductivity varies with water source: groundwater, storm runoff, rainfall, wastewater. Salts affect the quality of water used for irrigation or drinking. Every organism has a typical salinity range that it can tolerate.

Delta salinity is regulated to protect three broad classes of water use: 1) municipal and industrial; 2) agricultural; and 3) fish and wildlife.

Delta salinity is managed by the amount of Delta outflow that prevents saltwater from the Bay from flowing too far east. The California Department of Water Resources and the U.S. Bureau of Reclamation manage most of the waters stored upstream of the Delta, plus the flow control structures within the Delta and the pumps in the south Delta that transfer water into conveyances for export. DWR and the bureau have primary responsibility for managing salinity within the Delta.

Herrick described salinity-related crop effects in the south Delta. High salinity measurements create osmotic stress and foliar (leaf) injury to plants. The salt accumulates in the root zone, and the plant expends energy it would otherwise use to grow in order to draw water from the salt.

High sodicity, the ratio of sodium to calcium plus magnesium, results in loss of soil permeability, making it more claylike.

Increased levels of chloride, sodium, boron and other ions have direct toxic effects on plants. The most sensitive are dry beans, almonds and walnuts. Tomatoes, corn, alfalfa, melons, squash and vineyards are moderately sensitive. Safflower, wheat and sudan (sorghum sudan grass hybrid) are moderately tolerant, and asparagus and oats are the most tolerant.

Herrick said the San Joaquin River salts stay in the south Delta. The export pumps remove water, and upstream water dilutes the salt, but doesn’t push it out.

In preparing for the worst–multiple dry years–DWR has three alternatives: 1) reduce allocations; 2) petition the board to modify Delta standards; 3) plan for emergency drought rock barriers.


Roberta Long

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