What the National Academy of Sciences’ Report Means for the Bay Delta Conservation Plan

The recent report by the National Academy of Sciences’ National Research Council, confirming that protections for endangered species in California’s Bay-Delta estuary are “scientifically justified,” has received significant press coverage.  While the “spin cycle” noted by the Sacramento Bee in today’s editorial continues, as California Farmer admitted recently, “The farm spin aside, the report is not going to do what farm groups and politicians had demanded, that is ease regulatory restrictions and increase water supplies immediately. By that measure, the report did not deliver what farmers wanted.”  

Most of the focus of the news coverage has been on what the NRC report means with respect to the current litigation over the existing biological opinions (as well as Congressional attempts to suspend these Endangered Species Act protections).  However, the authors of the NRC report specifically wrote that their report was not “a legal judgment” as to the validity of the biological opinions.  Instead, this interim report from the NRC, and particularly their final report due next year, are designed to address “how to most effectively incorporate science and adaptive management” into future management efforts in the Delta, including the Delta Stewardship Council’s Delta Plan and the Bay Delta Conservation Plan (BDCP).  The NRC’s interim report and their final report will be hugely influential and important in this regard.

Most fundamentally, the National Research Council’s report means that the Delta Plan and BDCP must, at their core, utilize an adaptive management approach that links implementation of conservation measures (and operations of the state and federal water projects) to quantifiable outcomes in terms of the abundance and recovery of salmon, steelhead, and other listed species.  Many groups in BDCP have advocated for this approach for several years, as have the BDCP Independent Science Advisors' Report on Adaptive Management and the Delta Science Program's Review of the "Logic Chain" Approach.  In contrast, some interests in BDCP have pushed efforts to guarantee water exports based solely on making financial investments in certain conservation measures, regardless of the outcome in terms of whether fish populations continue to decline.  The NRC’s report should resolve this heretofore "unresovled issue" and put an end to this debate, helping BDCP move forward in designing a true adaptive management framework that links operations to quantifiable biological objectives and outcomes.  

In addition, the NRC’s report includes a significant critique regarding the potential benefits of restoring tidal marsh habitat for delta smelt (in contrast, the NRC’s report found that the benefits of floodplain restoration for salmon had a strong scientific basis).  The Department of Water Resources proposed inclusion of restoration of 8,000 acres of tidal marsh habitat in the delta smelt biological opinion, and BDCP is proposing to restore far greater acreage as a central element of the plan.  As the report notes, this action has been less controversial because it does not directly affect water users, but the NRC cautions that much more research is required on whether such restoration will benefit, or will actually harm, delta smelt and other pelagic species.  Substantial restoration of tidal marsh habitat in BDCP may not benefit the species and may not be a wise investment, particularly given the potential impacts of climate change and sea level rise.

Finally, the NRC’s report points out that the effects of other stressors may be large, and it recommends that “a holistic approach to managing the ecology of imperiled fishes in the Delta will be required if species declines are to be reversed.” The Delta Plan and BDCP are both supposed to address the full range of stressors, in order to lead to recovery of listed species (in comparison, the biological opinions are designed to keep the CVP and SWP from driving species to extinction).  NRDC could not agree more that both of these planning efforts should address all stressors, and utilize an adaptive management approach to ensure that implementation of conservation measures actually bring about the recovery of listed species.

NRDC has never argued that water exports are the sole cause of the species decline.  Indeed, we’ve often argued that measures to address other stressors, like water pollution, should be implemented to complement – but not substitute for – adequate flows in and through the Delta, and effective regulations on exports that harm and kill millions of fish.  Moreover, it’s important to recognize that water project operations also exacerbate and contribute to the effects of many of these other stressors, as many of the scientific experts testified at the recent public trust flow hearings before the State Water Resources Control Board.  And there is substantial scientific uncertainty over the magnitude of these stressors.  For instance, the current focus on striped bass by some interests seems potentially misguided, given that populations of striped bass have been declining along with delta smelt in recent years, and that far larger populations of striped bass historically co-existed with salmon, delta smelt, and other species for more than a century (as the NRC’s report notes, “[d]elta smelt have co-existed with many of these alien fishes for more than 100 years before the recent declines.”).  The NRC’s final report, due next year, and ongoing research at the Delta Science Program, should continue to improve our understanding of the effects of these so called “other stressors.”

Ultimately, as we move forward in designing solutions to protect and restore fish and wildlife in the Bay Delta estuary and improve water supply reliability, the National Research Council – and independent science more generally – must play a critical role.  Requiring rigorous independent scientific review of BDCP and the Delta Plan, including by the National Research Council and the Delta Science Program, would help ensure that the Delta Plan and BDCP are based on sound science, as intended by last year’s Delta legislation (see Water Code §§ 85280, 85308, 85320(c)).  And that’s something that everyone who is concerned with the health of the Bay-Delta estuary, California’s salmon fishery, and the reliability of our water supply, should support.