Research report says Delta water export cuts ‘scientifically justified’

WASHINGTON, D.C.
March 19, 2010 9:14am

Most of the actions proposed by two federal agencies to reduce water diversions in the Sacramento-San Joaquin Delta to protect fish are "scientifically justified," but just when the restrictions should be used is unclear, says a report from the National Research Council that was ordered by Congress.

The basis for the specific environmental triggers that would indicate when water diversions should be reduced is less well-supported by scientific analyses, says the new report.

“The Academy of Sciences report clearly validates the biological opinions,” says Ann Hayden, senior water resource analyst with the Environmental Defense Fund and a member of the Bay Delta Conservation Plan steering committee.

“It’s time to stop pitting the economic interests of farmers against fishermen and move forward to find solutions. We have pushed the Bay-Delta system to brink of collapse, and saving it -- and the jobs that depend on it -- is going to require increased cooperation among all interests,” she says.

“Massive curtailments in pumping have resulted in absolutely no improvement in the fisheries,” says Rep. Dennis Cardoza, D-Modesto. “This study finally is beginning to get at the truth and highlights the fact that farmers should not bear the entire burden for the decline of the species.”

“The committee’s most important work will take place in the coming months,” he says. “The examination of other stressors and the establishment of their relative importance in the decline of fish species are essential to obtaining an objective determination of the benefits of the actions taken and to provide for long-term, sustainable solutions for California’s water supply and ecosystem.”

Central Valley congressman Jim Costa, D-Fresno, says the report shows that water pumping is only one reason why fish populations are declining.

“One of the first steps to ensuring an increased and more reliable flow of water to the Valley is to recognize that there are multiple stressors degrading the health of the Delta,” says Mr. Costa. “I am pleased that the National Academy of Sciences has acknowledged that other factors like nonnative species, runoff, and the dumping of nitrates and ammonia have a large impact on Delta health.”

“The Council has reaffirmed how complex and long standing the issues are that involve the Sacramento-San Joaquin Delta,” says California Secretary for California Natural Resources Lester Snow. “We believe this points to the need for further work and flexibility in the implementation of the regulations and potential modification of the federal biological opinions.”

"The state views this report as evidence of the need for a long-term, comprehensive solution for the Delta,” he says.

Mr. Snow says he sees the report as supporting the Schwarzenegger Administration’s plans for the Delta.

“It calls for a 'holistic approach' to managing the Delta if specific declines in fishery levels are to be reversed and this is exactly the approach contemplated in the historic water legislation approved last fall and more specifically what has been long under way with our development of California's Bay Delta Conservation Plan,” he says.

U.S. Sen. Dianne Feinstein, D-Calif., says the report does not support further water export restrictions.

"I’d like to note that nothing in this report indicates that there is a need to enforce more rigorous pumping restrictions," she says.

"The finding that other stressors and predators -- such as the striped and largemouth bass, the silverside, and some species of catfish -- may have a potentially large impact on endangered species in the Delta is, in my view, extremely important," says Ms. Feinstein.

"For me, the key conclusion from this report is the need to integrate the two biological opinions, which would provide better clarity, better management, and stronger scientific justification for all federal actions in the Delta," she says.

The state's senior senator says the Departments of the Interior and Commerce should take "immediate action" to implement the biological opinions with additional flexibility wherever possible.

Ms. Feinstein says they should factor in the likely water limitations this April and May, "so that we can ensure that any federal actions to restrict water supplies are absolutely necessary.”

The California Farm Bureau Federation says the committee’s report supports an argument for better management of fresh water pumping.

“We believe the government must do a better job of managing the delta pumps, to make more water available to people while still protecting the fish. The report acknowledges that the existing water system can be managed better for people and fish,” says California Farm Bureau Federation President Paul Wenger. “It also reaffirms that our existing water system must be improved.”

“We know that other factors affect the fish,” he says. “We look forward to the follow-up report from the Research Council that will explore those factors in detail and offer recommendations on potential, long-term solutions.

Congress and the Interior Department asked the Research Council to provide a scientific evaluation of the biological opinions in 2008 and 2009 of the Fish and Wildlife Service and the National Marine Fisheries Service that called for actions to reduce the adverse effects of water diversions on delta smelt, Chinook salmon, Central Valley steelhead, and green sturgeon.

Those actions included restrictions in pumping Delta fresh water to the San Joaquin Valley. Farmers that normally use Delta water for irrigation let fields go fallow for lack of the normal supply of water.

The National Research Council committee that investigated the biological opinions concluded that in winter, high reverse river flows from high levels of pumping probably adversely affect smelt. Therefore, reducing the high reverse flows to decrease mortality of smelt is scientifically justified, it says.

However, the data do not permit confident identification of when to limit reverse flows of the rivers or a confident assessment of the benefits fish receive by reducing reverse flows, the committee found.

As a result, the implementation of this action needs to be accompanied by careful monitoring, adaptive management, and additional analyses, the NRC says.

The Delta gets its fresh water from the Sacramento and San Joaquin rivers and their tributaries, and the Delta's water ultimately flows into the San Francisco Bay and the Pacific Ocean. Tidal mixing from the Pacific Ocean also occurs, resulting in a brackish water ecosystem in many regions of the delta. In addition, pumping stations divert water from the delta, primarily for Central Valley agriculture and southern California metropolitan areas. The effects of an increasing population and the operation of the engineered water-control system have substantially altered the delta ecosystem, including its fish species.

For its study, the committee that wrote the report reviewed an action in the FWS alternative to protect delta smelt by limiting how much water is pumped from the delta to reduce reverse flows in the Old and Middle rivers, two branches of the San Joaquin River.

How the action in the FWS alternative to manage the contour line of 2 parts per thousand salinity, called “X2,” is beneficial to smelt needs further clarification, the committee says. The action is intended to increase outflows of water during the fall by maintaining the average position of X2 no farther upstream (east) of the Golden Gate Bridge than 74 kilometers in wet years and 81 kilometers in moderately wet years.

The FWS's argument for the action is that the average position of X2 is an indicator of suitable and available habitat for delta smelt. Preventing X2 from moving farther east on average requires the use of additional freshwater releases from reservoirs under some conditions.

The action is conceptually sound to the degree that the amount of habitat available for smelt limits their abundance, but the derivation of the details lacks rigor, the committee says. The committee says that the adaptive management requirements in the action should be implemented in light of the uncertainty about the biological effectiveness of the action and its possibly high water requirements.

In addition, the FWS requirement for creation or restoration of 8,000 acres of intertidal and subtidal habitat in the delta is weakly justified, because the relationship between tidal habitats and food availability for smelt is poorly understood, says the committee’s report. Because the details of implementation are not fully justified in the biological opinion, the committee recommends that this action be carried out in phases, with the first to include developing an implementation and adaptive management plan. The committee also recommends considering the sustainability of the resulting habitats.

Regarding the NMFS biological opinion, which applies to Chinook salmon, steelhead, and green sturgeon in the delta and farther upstream, the committee says that on balance the actions are scientifically justified. However, as with the FWS opinion, specific environmental triggers, thresholds, and flows should receive additional evaluation that is integrated with the analyses of similar actions for delta smelt, the report says.

In particular, the NMFS alternative contains an action similar to the FWS action to limit pumping in order to reduce high reverse flows in the Old and Middle rivers, and the committee says that high reverse river flows probably adversely affect the fish, but that the scientific support for specific flow targets is less certain.

The committee also says it found it difficult to ascertain the extent to which the collective watershed and tributary actions will appreciably reduce risks to the fishes within the watershed or throughout the entire river system and recommended a quantitative framework be created to assess survival.

The committee also considered whether any additional actions not included in the biological opinions might have the potential to provide equal or greater protection for the fishes than the current requirements, while costing less in terms of water availability for other uses. The committee says it found none that had received sufficient documentation or evaluation to be confident that any action had the potential to meet this objective, but will consider alternatives in more detail in its second report.

Adverse effects of all other stressors on the listed fish -- such as contaminants in the delta and structures on rivers that block fishes from access to their spawning habitat -- are potentially large, says the committee, which was asked to consider the effects of other stressors if time allowed.

The limited timeframe to complete the first report did not permit full exploration of the issue, but the committee will review it more thoroughly in its second report, scheduled to be released next year.

Moreover, the committee found that its evaluations and the agencies' evaluations were hampered by the lack of an integrated analysis that took all aspects of the fishes' life cycles into account, considered the effects of all the actions and fish species together, and included clear and well-documented considerations of the water needed to implement the actions.

However, such an analysis likely goes beyond the agencies' legal obligations under the Endangered Species Act, says the report.

Methodology

The report was sponsored by the U.S. Department of the Interior's Fish and Wildlife Service. The National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council make up the National Academies. They are independent, nonprofit institutions that provide science, technology, and health policy advice under an 1863 congressional charter. Committee members, who serve pro bono as volunteers, are chosen by the Academies for each study based on their expertise and experience and must satisfy the Academies' conflict-of-interest standards. The resulting consensus reports undergo external peer review before completion.