Sacramento: Clint Alexander, ESSA’s lead scientist for ecological water resources and Ryan Luster, Sacramento River Project Director for The Nature Conservancy California (TNC), were invited to make a presentation to the Delta Stewardship Council’s Independent Science Board, to update the Board on the ten year legacy and lessons of the creation and use of the Ecological Flows Tool (EFT), including the recent analysis of Bay Delta Conservation Plan (BDCP) future scenarios.

Since its inception in 2004, the EFT team has realized the vision of linking hydrogeomorphic models with a representative suite of functional ecosystem indicators, creating a single decision analysis tool for evaluating trade-offs for multiple species and locations.

Over the course of a two-hour presentation and discussion, Board members asked insightful questions and provided very supportive feedback. They were especially supportive of the major advances noted in the Final EFT Project Report (April 2014). The Board applauded the milestone of having developed a working software system which permits the simultaneous evaluation of multiple species over space and time, which highlights the trade-offs which are inevitable when aquatic and riparian species have differing water requirements.

Secondly, the Board was also interested to learn about a successful pilot experiment in which ideas for operational improvements obtained through the analysis of EFT results were subsequently fed back into the Department of Water Resources CALSIM-SRWQM-DSM2 hydrologic simulation system, to test whether improved habitat conditions for winter-run Chinook and Delta smelt could be balanced with water management obligations. The importance of selecting ecologically-meaningful reference cases in effects analysis studies (like BDCP) was also a shared point of concern, particularly in relation to future climate change effects on endangered species.

The Board was particularly interested to see how EFT findings clearly demonstrate that the existing water management paradigm needs to fundamentally evolve to become far more flexible when addressing ecosystem needs themselves (regardless of water delivery needs). Alexander and Luster advocated for the creation of a far more agile system in which static flow, water temperature and ecological criteria are replaced by an adaptive state-dependent system that dynamically alters priorities amongst ecological objectives depending on both hydrologic conditions and the recent past history of habitat conditions experienced by various focal species. According to the TNC and ESSA team, this “smarter” flow management paradigm provides greater flexibility to balance both ecosystem needs and water supply reliability. Mr. Alexander and Mr. Luster noted that additional research to further demonstrate this new approach is underway with support from TNC.

Funding support for EFT has been provided by the CALFED Bay-Delta Ecosystem Restoration Program, as well as through independent funding provided by TNC and ESSA Technologies.

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ESSA will be presenting the lessons from EFT at the 8th Biennial Bay-Delta Science Conference October 28-30 in Sacramento, California.