Ecosystem Management Decision Support (EMDS) Applied to Watershed Assessment on California’s North Coast

In 2001, the state of California initiated the North Coast Watershed Assessment Program (2003a) to assemble information on the status of coastal watersheds that have historically supported anadromous fish. The five-agency consortium explored the use of Ecosystem Management Decision Support (EMDS) (Reynolds and others 1996) as a means to help assess overall watershed and in-stream conditions for fish. EMDS is expert system software developed by the USDA Forest Service for similar efforts with the Northwest Forest Plan (2000). NCWAP developed models to help assess key watershed characteristics that contribute to shaping channel morphology and to evaluate the present stream habitat conditions in terms of suitability for anadromous salmonids. The stream condition model uses data collected during DFG stream surveys to evaluate the present stream habitat conditions for migrating, spawning and rearing anadromous fish. Factors evaluated by the model include percent of reach in moderately deep pools, pool shelter complexity, streamside canopy density, and spawning gravel embeddedness. We also developed a model addressing indirect terrestrial influences on anadromous fish in a watershed. The Potential Sediment Production Model estimates the impacts of both natural background and human-related effects on in-stream sediment delivery. NCWAP scientists learned several important lessons from using EMDS. Critical aspects of EMDS include the hierarchical structure of the model, the selection of the operators at the nodes of the networks, and the selection of breakpoints used in evaluating specific environmental data