Understanding How Snowmelt Manifests in Streamflow

Abstract:

Snow is a distinctive feature of the hydrological cycle, unlike the many diffusive hydrological processes, large snowpacks accumulate precipitation over several months, and then release it relatively quickly. Although the detailed physics of snowpack accumulation and melt are relatively well understood at the point scale, their manifestation at the catchment scale remains complex. In this talk we summarise a number of recent advances that contribute to improved understanding of snow and its impact on streamflow. These include a new way of classifying hydrologically different types of snow-dominated environments using similarity indices, a model of climate-snowpack relationships obtained by simplifying the temperature index method, and new evidence of the impact of snow on streamflow, indicating that, other things being equal, catchments with less snow produce lower mean streamflow. With future temperature warming, snowfall is likely to decrease, and the new result suggests that streamflow would tend to decrease as a consequence, with greatest proportional impact in arid snow-dominated catchments.