Habitat Assessment for the Shasta Dam Fish Passage Evaluation

Evaluation of historically available anadromous salmonid habitat above major rim dams bordering California’s Central Valley has been required under the current BiOp for the federal Central Valley Project prior to reintroduction of ESA-listed salmon as part of recovery actions. Efforts have begun to obtain a better understanding of the distribution and suitability of remaining potential habitat above the dams. As part of planning for pilot-level salmon reintroduction above Shasta Dam, the U.S. Bureau of Reclamation used a spatially-explicit habitat classification system, with data collected from a combination of geo-referenced, aerial videography and ground surveys of representative sites in the upper Sacramento and McCloud rivers. Both rivers exhibit fair-to-good habitat conditions that could potentially support spawning and rearing of the endangered winter-run Chinook Salmon. The upper Sacramento River has less potentially suitable spawning habitat, with optimal summer temperatures (the season when the winter run spawns), than does the McCloud River, although the amount of suitable juvenile rearing habitat would be similar for both rivers. The temperature regime of the upper Sacramento River would likely be a major factor limiting the number of winter-run Chinook Salmon that could be successfully reintroduced to that tributary above Shasta Dam.