Steelhead Salmon Intrinsic Potential - North Central California Coast - NOAA [ds2787]

Information on estimating the quality and extent of historical habitat is needed for ongoing efforts to conserve and eventually recover protected populations of Pacific salmonids. Because georeferenced spatial data on habitat and fish distribution at the regional scale are lacking, we adapted methods of the Coastal Landscape Analysis and Modeling Study (CLAMS) to implement a GIS approach in modeling the intrinsic potential (IP) of stream reaches to support juvenile steelhead, coho, and chinook salmon. The IP model uses geomorphic and hydrological attributes (expressed as the weighted geometric mean of indices for mean annual discharge, channel gradient, and channel constraint) to estimate the latent potential of stream reaches to provide favorable habitat characteristics for spawning and rearing. Indices for the model are derived from a 10 m DEM and PRISM precipitation data. Thus, the model predicts patterns of relative productive potential expected in the absence of human disturbances, as related through the input data. To apply the model appropriately in California, we investigated the species-specific weighting functions (proposed by CLAMS) for coho and steelhead using values available in the literature. Also, because patterns in precipitation and runoff vary across latitudes, we appplied a linear regression model to gage station data to better estimate mean annual discharge from drainage area and precipitation.

See Agrawal, A., R. Schick, E. P. Bjorkstedt, S. R.G., M. Goslin, B. C. Spence, T. Williams, and K. M. Burnett (2005). Predicting the potential for historical coho, Chinook and steelhead habitat in Northern California. NOAA Technical Memorandum NMFS-SWFSC-379.

Spence, B., E. Bjorkstedt, S. Paddock, and L. Nanus (2012) Updates to Biological Viability Criteria for Threatened Steelhead Populations in the North-Central California Coast Recovery Domain.