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Delta Science Program Independent Panel Helps State Water Board With Flow Objectives

February 2014

Following a two-day public workshop in early February, a panel of independent scientists convened by the Delta Stewardship Council’s science program is preparing a report intended to help narrow areas of scientific disagreement and uncertainty over the flows necessary for a healthy Delta estuary.

The report is expected to be completed by mid-March, and will be used by the State Water Resources Control 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 those flow objectives is one of the requirements for consistency with the Council’s Delta Plan (Chapter 4, Ecosystem Restoration Policy 1 (23 CCR section 5005) and Recommendation 1).

“Healthy rivers and estuaries, and the native species that live in them depend on naturally variable water flows and a dynamic landscape. At the same time, however, reliable water supplies have been associated with artificially stabilized flows and a complex human-made system of infrastructure that includes dams, levees, and channelized rivers and sloughs,” said the Council’s Deputy Executive Officer for Science Rainer Hoenicke.

Finding the right balance is at the core of the state’s coequal goals for the Delta: providing a more reliable water supply for California and protecting, restoring and enhancing the Delta ecosystem. And it’s the subject of much scientific and political debate.

“The Bay-Delta system is complex and there is a lot of science being produced and promoted by various agencies and stakeholders,” said Science Program Manager Sam Harader. “The experience and perspectives of an independent panel of top scientists can go a long way towards helping the Board with the scientific basis for these difficult flow and water quality decisions.”

Harader said the Council’s science program created the independent panel by choosing experts from both the U.S. and Canada. The members have multidisciplinary backgrounds in hydrology, hydrodynamics, and biology, and many have a working knowledge of the Delta’s issues. [Click here to see bios of the panelists.]

“Creating these panels is a bit of an art,” said Harader. “The panel must have a familiarity with the Delta, but the members cannot be so involved in the region that it creates a conflict of interest. That’s what makes the panel truly independent.”

Based on the initial charge the panel was given, Harader says the members first reviewed the regulatory history behind the current Delta outflow standards that were adopted by the Board in 1995. The objective was to determine why and how the Board reached its conclusions for the current standards.

The members then reviewed a series of presentations from various water-related agencies and stakeholders. The subjects were wide-ranging and included, in addition to flow and habitat, the effect of treated wastewater, salinity encroachment, and the changing use of pesticides in the Delta region, among others. All of the presentations can be found on this webpage.

“The presentations included views on what the presenters felt was important and what’s not important about the current outflow standards based on their particular scientific perspective,” said Harader. Following each 15-minute presentation the panel members queried the stakeholders to gain a deeper understanding of the individual presenter.

Next, Harader says the panel reviewed presentations on hydrology and hydrodynamics. In particular, the members learned the effects the flows have on fish and the larger aquatic food chain. Again the members had an opportunity to ask questions following each presentation. Harader says the two days of presentations actually supplements some four dozen other reports and documents that relate to flows the Program has asked the panel members to review.

“Using both sets of information, the panel will create a synthesized report that identifies, among other things, what the members believe is the “best available science” that should be used when determining the outflow updates for the Board’s Bay-Delta Plan,” said Harader.

The completed report will be presented to both the Board and the Council’s science program as an authoritative, basis of scientific recommendations for research and a neutral decision-making process.

For more background information about the Workshop on Delta Outflows and Related Stressors, visit this web page on the Council’s website.

This independent panel workshop is one of four the science program is currently hosting or has recently organized to assist other state agencies. Other topics include fish species predation, water flows within the Delta, and nutrient research within the Delta. To stay abreast of the latest Delta science program events, visit this web page on the Delta Stewardship Council website.

Coequal goals

The Delta Stewardship Council was created in legislation to achieve the state mandated coequal goals for the Delta. "'Coequal goals' means the two goals of providing a more reliable water supply for California and protecting, restoring, and enhancing the Delta ecosystem. The coequal goals shall be achieved in a manner that protects and enhances the unique cultural, recreational, natural resource, and agricultural values of the Delta as an evolving place." (CA Water Code §85054)