Environment Canada's hydrological forecasting system

Environment Canada's Canadian Meteorological Centre (CMC) is preparing to deploy an operational streamflow forecasting system. The system is highly automated, flexible and portable. Input estimates of surface runoff, subsurface lateral flow and base flow are provided by Environment Canada's (EC) land-data assimilation (LDAS) systems and numerical weather forecasting (NWP) systems. The various models produce deterministic forecasts of 48 hours to 10 days at horizontal resolutions ranging from 2.5 to 25km. The routing model, WATROUTE, simulates the progress of these input flows through the river channel network at an approximately 800-m horizontal resolution. Flow directions and terrain elevations are taken from the USGS HydroSHEDS database. Surface roughness and degree of channel meandering are estimated from geophysical and vegetation databases. EC's operational LDAS and NWP systems currently rely on the Canadian version of the ISBA land-surface scheme, which should soon be replaced by the new SVS scheme. An evaluation of the system skill, when forced by either the legacy ISBA or the new SVS land-surface scheme is presented.