Numerical Modelling of Freshwater Flux and Temperature on the Northern British Columbia Coast in support of Marine Oil Spill Response

Abstract:

Canada has the longest coastline of any country (>120,000 miles). Canadian response to potential oil spills along its coast is being improved under a high-level federal government strategy, falling under the rubric of the World Class Tanker Safety System (WCTSS). The first component of this strategy focuses on the Kitimat area and its marine approaches on the northern British Columbia (BC) coast. This initiative reflects concerns around both existing ship traffic, and potential increases in tanker traffic associated with the proposed Northern Gateway pipeline. The project includes joint development, between multiple federal departments, of an operational modeling system to predict currents in the coastal ocean. One of Environment Canada’s (EC) contributions is the development and implementation of a short-term forecast model of river flows with corresponding stream temperatures. These quantities influence currents in the coastal ocean, which in turn affect oil spill fate and transport.

Our platform is based on the Surface Prediction System (SPS), which is essentially a driver for a land surface scheme (LSS) linked to a hydrological routing model, and is related to the earlier MESH platform. LSS’s under consideration for use in this mountain rainforest environment are the Canadian Land Surface Scheme (CLASS), and the Soil and Vegetation Simulator (SVS), which is an evolution of the Interactions Soil-Biosphere-Atmosphere (ISBA) model. Runoff and drainage outputs are then routed through the stream network by WATROUTE. The River Basin Model (RBM), a physically-based stream temperature simulator, is also being integrated into SPS to additionally enable water temperature forecasting. The freshwater modelling system will be directly driven by EC’s numerical weather prediction (NWP) systems.

Preliminary results from this ambitious modeling program are presented, along with recommendations for improvements to physical process representation in the various models employed.