Cowichan Estuary Eelgrass Habitat Suitability Model

The Cowichan Estuary Restoration Project is a multi-year project being conducted by Cowichan Tribes to help enhance the recovery of Cowichan Chinook salmon stocks in the Salish Sea. The objective of this model was to use existing information to identify areas within the Cowichan estuary that may be suitable to support eelgrass habitat. Parameters assessed included sediment types, wave exposure, water depth, water quality (i.e. temperature, pH, salinity, and DO), current velocity, H2S, bed mobility, active channel classification, and crown land tenures (i.e. log handling). Raster layers of the study area were modeled for each variable and methods were adapted from Short et. al. (2002) where parameters were re-classified as within the optimal eelgrass tolerance limits (assigned a value of 2), within acceptable tolerance limits but not optimal (assigned a value of 1), or unsuitable for eelgarss (assigned a value of 0). Parameters were then combined in a multiplicative model, where areas with a final higher number represented zones with more optimum conditions, areas with a lower final number represented zones within the tolerance limits of eelgrass but not within optimal conditions, and areas with any parameter identified as unsuitable (i.e. "0") removed from the model.