Simulated impact of climate change on hydrology of multiple watersheds using traditional and recommended snowmelt runoff model methodology

For more than two decades researchers have utilized the snowmelt runoff model (SRM) to test the impacts of climate change on streamflow of snow-fed systems. SRM developers recommend a parameter shift during simulations of future climate, but this is often omitted. Here we show the impact of this omission on model results. In this study, the hydrological effects of climate change are modeled over three sequential years with typical and recommended SRM methodology. We predict the impacts of climate change on water resources of five subbasins of an arid region. Climate data are downscaled to weather stations. Period change analysis gives temperature and precipitation changes for 55 general circulation models which are then subsampled to produce four future states per basin. Results indicate an increase in temperature between 3.0 and 6.2 °C and an 18% decrease to 26% increase in precipitation. Without modifications to the snow runoff coefficient (c_S), mean results across all basins range from a reduction in total volume of 21% to an increase of 4%. Modifications to c_S resulted in a 0–10% difference in simulated annual volume. Future application of SRM should include a parameter shift representing the changed climate.