SWRCB's Delta Flow Recommendations Aren't a Surprise

Last week, the State Water Resources Control Board issued a report recommending increased flows to protect fish and other Public Trust resources in the Delta.  While there’s been a lot of argument over what the report means and how it should be used, there’s been very little debate over the scientific evidence used in the report.

On the one hand, this seems pretty surprising, since the California Department of Water Resources and the State and Federal water contractors argued that no protections beyond D-1641 are scientifically justified (in effect, they propose to eliminate the protections in the Delta that the federal Court in 2007 found were required to prevent fish from becoming extinct, and the protections required by the federal fishery agencies in 2008 and 2009 to protect salmon and other threatened and endangered species). 

But on the other hand, I’m not very surprised by the lack of argument about the science embodied in the report, since only the water users took that position, and virtually every other academic scientist, agency scientist, or stakeholder who testified before the State Board argued that increased flows were necessary to protect the estuary and its fish and wildlife.

In reality, there’s hardly any scientific debate that increased flows are necessary to protect fish and wildlife in the Delta; the real debate is about what the right flow regime would be, and how best to implement adequate flows for fish and wildlife while improving water supply reliability for cities and farms.  Policy makers and scientists have been warning for years that management of flows in the Delta is unsustainable, and that greater environmental flows are necessary. For instance: 

  • Governor’s Delta Vision Strategic Plan specifically recognized that, “[t]he flow and water quality standards of the Water Board’s Decision 1641 (D-1641) are increasingly recognized as inadequate.”  In order to improve water flows to restore the ecosystem and species, the Strategic Plan recommending increasing spring Delta outflow, restoring fall outflow variability, increased San Joaquin inflows from February to June, and short term fall pulse flows.  It specifically recommended targeting February to June Delta outflow based on a percentage of unimpaired flows.  (Delta Vision Strategic Plan, pages 83-87)
  • The Public Policy Institute of California’s work on the Bay-Delta has consistently (if implicitly at times) assumed that even with a peripheral canal, there would be lower exports than in recent years.  Their report, Comparing Futures for the Sacramento-San Joaquin Delta, assumed export volumes at 1981–2000 levels, or approximately 5 million acre feet per year.  (See pages 45 & 47)  These export levels are similar to export levels permitted under the recent biological opinions.  More recently, the PPIC explicitly stated (see page 5that even with a peripheral canal, “water users must be prepared to take less water from the Delta, at least until endangered fish populations recover.”
  • The Chief Scientist of the CALFED Science Program testified to the Board that “recent Delta environmental flows are insufficient to support native Delta fishes for today’s habitats,” that flow and habitat are not interchangeable, and that current flows harm native species and help invasive species.
  • The National Research Council of the National Academy of Sciences recently concluded that protections for endangered salmon, delta smelt, and other species in the Delta, which require greater environmental flows and are largely incorporated into the Report, generally are “scientifically justified.”  So too did numerous peer reviews of the two biological opinions, both before and after they were released.

It’s also important to recall that the Board has wrestled with similar flow requirements in the past.  For instance, in 1992 the Board proposed adoption of draft Decision 1630, which would have imposed some significant protections, including limitations on reverse flows in the delta, increased inflows and outflows, and significant export limitations during certain times of year.

So the Report's conclusions come as little surprise for those who have followed water issues in the Delta, since they echo scientific, policy and legislative recommendations over the past several years and decades.  And the report includes extensive evidence justifying its conclusion that the flow recommendations are based on the best available science.  Hopefully all five Board members agree that the report is based on the best available science, revise the executive summary to more accurately reflect the conclusions in the report, and vote to adopt the Report on August 3. 

About the Authors

Doug Obegi

Senior Attorney, Water program

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