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The Ecological Flows Tool (EFT) is a decision support tool emphasizing clear communication of trade-offs for key ecosystem targets associated with alternative conveyance, water operations and climate futures in the Sacramento River and San Francisco Delta eco-regions. Practical integration of multi-species, multi-habitat needs in the evaluation of water operation scenarios is challenging. EFT facilitates the inclusion of a broad suite of ecological considerations into water use planning exercises. We take a bottom-up, process-based view of how flow and related aquatic habitat variables (e.g., salinity, temperature, turbidity) are tied to a variety of ecosystem functions for representative sets of focal species and habitats (chinook salmon, steelhead, green sturgeon, Delta smelt, splittail, tidal wetlands, invasive species deterrence, bank swallows, channel erosion/migration, Fremont cottonwoods, large woody debris recruitment). By leveraging many of the same planning models used in existing socioeconomic evaluations in California (e.g., Calsim, DSM2), EFT provides an “eco plug-in” to the water studies based on use of these models. Our vision is to link physical models to a representative sampling of individual ecosystem components inside an overall compressed, cross-disciplinary synthesis tool for evaluating conveyance operation alternatives both in the Delta and Sacramento River eco-regions.
When expanding the number of ecological targets considered in water use planning, practical synthesis becomes a challenge to disseminate, especially to an audience with various levels of understanding. EFT outputs are accessible through the EFT Readersoftware tool which emphasizes simplicity, such as traffic light roll-ups that quickly reveal the rank order ecological performance of alternatives, as well as more detailed results on target and avoidance flows by location and time-period. The current version of the EFT Reader supports ecological trade-off evaluation in the Sacramento River eco-region (SacEFT), with inputs derived from the Sacramento River Ecological Flows Study (the “Study”) and subsequent peer reviews. (Results of the Study, a synthesis of two decades of restoration work by The Nature Conservancy and partners, are available at www.dfg.ca.gov/ERP/signature_sacriverecoflows.asp .) More recently, EFT is also being used to support evaluations of the Bay Delta Conservation Plan’s proposed conveyance and habitat restoration measures. Currently, with support from a Calfed ERP grant, The Nature Conservancy and ESSA are extending EFT for the San Francisco Delta eco-region. This work naturally builds on the SacEFT effort. Delta focal species and habitats include chinook, steelhead, Delta smelt, splittail, tidal wetlands and invasive species deterrence. Completion of the Delta Ecological Flows Tool (DeltaEFT) branch of the EFT software will provide the ability to explicitly link upstream Sacramento River eco-region responses (via SacEFT investigations) to ecosystem responses in the Delta (using the DeltaEFT branch of the EFT software system).
One of the biggest challenges in the practical implementation of ecological flow guidelines is the wide range of objectives, focal species and habitat types that need to be considered. Our work to date has brought into focus how these various objectives cannot all be simultaneously met. In nature, conditions often benefit one target or species to the potential detriment of another in any given year. Fortunately, flow characteristics that benefit the various ecological targets investigated are usually required on a periodic basis and not every single year. EFT studies simplify communication of these trade-offs, and catalyze definition of state-dependent management practices that promote the development of needed flexibility in the water management system.
In the end, our multiple focal species approach reduces the shortfall in ecological evaluation capability. The long-term goal is to work with leaders in water planning forums to continue the development of the SacEFT and DeltaEFT components of the Ecological Flows Tool to best meet the needs of these groups.
Funding for EFT was provided by the CALFED Bay-Delta Ecosystem Restoration Program.
Disclaimer: No computer program can replace your common sense, or make decisions for you. You therefore assume complete responsibility for decisions made or actions taken based on information obtained using this software.