Abstract: 

In February 2005, members of the Scott River TMDL technical advisory group met in Ft. Jones, California, to review a number of elements of the ongoing work performed by the North Coast Regional Water Quality Control Board, including their affiliates. The TAG members had the opportunity to review preliminary results from a macro-scale stream shade indexing model, RipTopo. This model, developed by UC Davis scientists and funded by the Regional Board, accounts for riparian and topographic shading conditions and is intended to support development of the temperature TMDL in the Scott River watershed. RipTopo used existing statewide vegetation data, augmented by existing riparian vegetation digitized from aerial photographs, to depict the current and potential height of streamside vegetation in the watershed. The TAG members who reviewed the model results expressed concern about the lack of site specificity when depicting potential vegetation height conditions in selected areas of the watershed, particularly in those areas, which currently lack forest cover. The members felt that the TMDL effort could be improved through additional scientific input and recognition of potential ecological and land-use constraints in selected reaches of the watershed. In response to these concerns, this report covers elements of 1) an extensive review of the technical, scientific, and historical literature relevant to potential riparian conditions in the Scott River watershed; and 2) the input from a combination of local expert stakeholders, agency scientists, and ecological scientists who reviewed in the field existing conditions in particular sub-watersheds. This report is intended as written findings from the supplementary review of the literature, and ecological conditions identified in the site visits, to be evaluated by the North Coast Regional Control Board as part of the temperature TMDL for the Scott River.