Modelling Estuarine Exchange through Boundary Pass

Estuarine circulation in the Strait of Georgia consists of a surface brackish outflow (the freshwater predominantly from the Fraser River) and a deeper return flow that varies in depth seasonally. Transport to and from the open ocean is mainly to the south through Boundary Pass and Haro Strait. We have configured a regional implementation of the NEMO model for the Salish Sea. It is baroclinic, forced by hourly 2.5 km resolution winds, sea-surface height at the mouth of Juan de Fuca Strait, daily Fraser River flows, and climatology for another 149 rivers. We model 8 tidal constituents. We will discuss model evaluation against observations. As a southern boundary to the Strait of Georgia we focus on a vertical cross-section across Boundary Pass. We will present depth profiles of fluxes of freshwater through this cross-section as a function of tides, river flow, Juan de Fuca density, winds and in addition, as a function of various modelling parameters