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The Delta Ecological Flows Tool: record of design (v1.1)
The Ecological Flows Tool (EFT) is a decision support system that demonstrates how changes in flow management (and other actions) result in changes to the physical habitats for multiple species within the Sacramento River and the San Francisco Delta. This document provides the as-built Record of Design for the focal species and habitat indicators developed for version 1 of the Delta Ecological Flows Tool (DeltaEFT) branch of EFT. The Record of Design for the Sacramento Ecological Flows Tool (SacEFT) version 2 branch of EFT is documented separately (see: ESSA 2011a). Between 2004 and 2008 The Nature Conservancy (TNC) conducted the Sacramento River Ecological Flows Study in which TNC and its project partners developed a decision analysis tool that incorporates physical models of the Sacramento River with biophysical habitat models for six Sacramento River species. The resultant tool, SacEFT, links flow management actions to focal species outcomes on the mainstem Sacramento River (see ESSA 2011a for details). Building on the success of SacEFT, this software architecture was extended starting in 2008 to include a range of Delta specific ecological indicators and management actions through construction of version 1 of the DeltaEFT branch of the software. Version 1 of DeltaEFT, the subject of this document, was completed in September 2012. Importantly, completion of DeltaEFT now provides the ability to explicitly link upstream (Sacramento River) ecological responses evaluated with SacEFT to ecosystem responses in the Delta evaluated with DeltaEFT. "SacEFT" and "DeltaEFT" are collectively referred to as "EFT". EFT works by integrating a range of representative functional ecological response indicators with key physical variables obtained from widely used hydrologic models (e.g., CalSim, DSM2, USRDOM). EFT more transparently relates multiple attributes of the flow regime to multiple species’ life history needs, contributing to an effective understanding of flow and non-flow (gravel augmentation, rip-rap removal, levee set-back) restoration actions on multiple focal species and their habitats. The hallmark of the EFT approach is integration and clear communication of ecological trade-offs associated with different water operation alternatives. This capability has been illustrated in recent applications of EFT to EIS/R investigations for North of Delta Off-stream Storage (NODOS; TNC and ESSA 2011) and the Bay Delta Conservation Plan (BDCP; ESSA 2011b and see BDCP Plan documents1). EFT is structured as an ‘ecological plug-in’ to existing physical models that are commonly used for water planning in the Central Valley. Rather than reinventing models, EFT utilizes output data sets from daily disaggregations of CalSim, DSM2 and other models that are used to investigate water delivery and other standards set for the CVP and SWP water system. EFT utilizes these data and adds ecological calculations (algorithms) to evaluate effects of water re-operation and conveyance and storage project changes on multiple ecosystem targets.