Appendix B: Development of a Hydrodynamic Model of Cowichan-Koksilah River Estuary and Cowichan Bay

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. Northwest Hydraulic Consultants Ltd. (NHC) was hired by Cowichan Tribes (CT) to conduct geomorphic studies, field investigations and numerical modelling in support of the project. The purpose of these studies was to provide an overview of the watershed, river system, delta and oceanographic conditions in Cowichan Bay, document changes to the physical characteristics on the tidal flats, summarize the key boundary conditions that govern the physical character of the delta and estuary, and carry out field measurements and hydraulic modelling to characterize the flow and sediment transport characteristics in the estuary. This appendix describes the hydrodynamic model including the creation of a Digital Elevation Model (DEM), model grid and bathymetry, boundary conditions and validation, and results.