The impact of climate change and harvest of mountain pine beetle stands on streamflow in northern British Columbia.

This research examines the impact of climate change and MPB harvest on streamflow in northern British Columbia using the Hydrologiska Byr~\u2022ns Vattenbalansmodell-Environment Canada model (HBV-EC) a semi-distributed conceptual hydrologic model. Streamflow for the Goathorn Creek watershed in Telkwa is modeled under the IPCC A1B, A2 and B1 emissions scenarios. The TreeGen downscaling method and four global climate models were used to generate future climate. Global climate models used were the Canadian developed CGCM3, ECHAM5 from Germany, GFDL-CM2.1 from the United States and CSIRO-Mk from Australia. Under all climate scenarios HBV-EC modeled a 16 percent reduction in mean annual flows the timing of spring peak flows was also forecast to occur up to 30 days earlier in the year. A change in the timing of peak flows and an overall reduction in mean flows will have important implications for water managers, domestic users and industrial development within the Bulkley Valley. The HBV-EC model was also used to model Moffat Creek streamflow under various harvest scenarios for mountain pine beetle stands. The model predicted an increase in streamflow with an increase in harvest area. When compared to measured streamflow it was however found that average spring discharge during the MPB epidemic was 14 percent lower than it had been during the previous 30 years. The low spring discharge during the MPB epidemic appeared to be related to the 9 percent decrease in SWE for the same years however further investigation is required.