Past and future contributions of glacier melt to Columbia River streamflow

The Columbia River is the largest river in the Pacific Northwest of North America, with headwaters in both Canada and the United States. It is heavily developed for hydroelectric power generation, and flow releases from reservoirs in Canada are governed by the Columbia River Treaty, which may be reviewed over the next few years. As part of background research to prepare for this possibility, teams in both Canada and the United States are assessing the potential influence of climate change on water resources. In a study funded by BC Hydro, researchers from the University of British Columbia, the University of Northern British Columbia and the Pacific Climate Impacts Consortium are focusing in particular on the potential effects of glacier response to future climate scenarios. The approach involves the application of a fully distributed glacier dynamics model and a semi-distributed hydrologic model, each driven by weather variables downscaled from General Circulation Model output. The calibration of the hydrological model is constrained by forcing the simulated glacier mass balance to match volume changes computed from digital elevation models of the glacier surfaces. This presentation focuses on challenges in linking hydrological and glaciological models for simulating transient response and provides some initial results from the hydrological and glaciological models.