Exploration of a Unified Process Interpretation for Seasonal and Annual Water Balances in Snowy Catchments

Snow accumulation and melt dynamics provide influences on streamflow seasonality and mean annual flow which are not present in snow-free areas. Most studies of snow hydrology focus on one timescale, which limits and fragments the understanding of catchment behaviour. Establishing which process controls on hydrological responses act across multiple time scales is still challenging due to the wide range of climates and landscape conditions that may affect the catchments’ hydrological functioning. Here, we build upon prior research that showed how climate and soil drainage effects both shape seasonal and mean annual water balances in humid, snow-free catchments. We establish process controls on seasonal and mean-annual hydrological responses to unify the process interpretation across time scales for diverse snow-influenced catchments. We use observed streamflow, climate and catchment attributes data in snow-affected catchments from the CAMELS_US dataset to assess the impacts of climate and landscape on catchment responses. We use a conceptual model to unify the mechanistic explanation for seasonal and mean annual water balances. We hypothesize that the interaction between climate aridity, the fraction of precipitation falling as snow, and landscape properties (soil, geology and topography) in snow-affected catchments shapes both streamflow seasonality and mean annual flow.