The purpose of the project was to evaluate several alternative instream flow methods, then recommend a scientific framework and specific methods for determining instream flow needs to promote salmonid recovery and protection in the Shasta River basin. Quantifying instream flow needs is critical to restoration. Our goal was to recommend a framework best suited for the Shasta River basin that will facilitate compliance with Fish and Game Code 5937 and the Watershed-wide Permitting Program (CDFG 2008). An instream flow needs study must assess the extent to which the natural flow regime can be altered while still ensuring the health of salmonid
populations and riparian communities (Richter et al. 1997, Anderson et al. 2006). Or conversely given the status of water allocation and salmonid populations in the Shasta River basin, an instream flow needs study must determine how much additional streamfl ow is needed to promote recovery of viable salmonid populations. This determination requires a scientific framework rooted in ecological principles. An instream fl ow needs study must also be concise and transparent to ranchers, local nonprofit t groups, regulatory agency scientists and policymakers, the Resource Conservation District (RCD) staff, and other interested scientists.