Glacier and snow melt provide the majority of runoff in British Columbia’s Bridge River System, where water flows through three dams in succession to generate about 7% of the province’s hydroelectricity. Climate change-related glacier retreat and a reduction in seasonal snowpack threaten the reliability of late-summer reservoir inflows. Current operational hydrologic models do not account for glacier loss, posing challenges for long-term water resource planning.

To address this gap, we developed hydrologic models using the Raven modelling framework for the three watersheds supplying the Bridge River System. Using the Open Global Glacier Model, we simulated the evolution of 194 glaciers in the region through 2100 and incorporated projected glacier area changes into the hydrologic models to represent land cover evolution from 1985 to 2100.

Simulated future reservoir inflows and stream temperatures indicate an earlier freshet and earlier summer recession, with the greatest late-summer flow reductions occurring in the most glacierized basins. Observed stream temperature trends since 2013 demonstrate warming, and our projections indicate further increases of 3°C to 7°C by 2100. This study highlights the complexities of hydrologic modeling in remote, mountainous catchments with steep climatic gradients and presents novel methods for integrating land cover change and stream temperature estimation. Our findings will support future operational studies and reservoir temperature modeling in the watersheds, providing valuable insights into the system’s vulnerability to climate change.