Name
Hydrologic Modelling of the Fraser River Basin for Multivariate Climate Impact Assessment
Description
The 2021 flooding in the Fraser River Basin requires additional insight for future infrastructure design that accounts for the impacts of climate change. To better understand the historic hydrologic cycle and the effects of climate change on streamflow, we apply the Hydrologic Predictions for the Environment (HYPE) hydrologic model to simulate the historic and future hydrology. Model parameters (192) are calibrated using the Dynamically Dimensioned Search algorithm with a calibration budget of 50,000 model runs and approximately ten trials based on the median NSE of all simulated gauges within the basin (51 gauges). Model performance is satisfactory, with a median KGE of 0.49 and NSE of 0.44 across the entire Fraser Basin (simulated subbasins had a simulated to observed area difference within 10%). The model simulates streamflow for the entire Fraser River just upstream of the Vancouver metro region well with a KGE of 0.76 and an NSE of 0.55. Efforts are now focusing on assessing the impacts of climate change on flow quantiles by forcing the model with a set of CMIP 6 climate simulations for RCP 4.5 and RCP 8.5 scenarios from 2020 to 2100. Because climate change has increased the occurrence of higher magnitude flooding events, this HYPE model has been developed and calibrated under the awareness of the variability that climate change has on the hydrology of a basin, which will allow for non-stationary flood assessment.