The Southwestern United States, known for its pronounced hydroclimatic variability across both spatial and temporal scales, has been the subject of significant research focused on water resource vulnerability to climate change. Yet, critical uncertainties remain about how rising temperatures may disrupt water supply reliability—particularly in basins reliant on seasonal snowpack. Climate change has likely contributed to decreased snow accumulation and faster melt rates, which directly affect water resource management in snow-dependent regions. The Beaver Creek watershed, facing these challenges, is an essential component of water availability for the Phoenix metropolitan area, underscoring the need for deeper insights into its hydrological dynamics to support sustainable water management. Previous modeling efforts to simulate streamflow of Beaver Creek show significant negative biases during wet winters. The proposed research will evaluate if the physics-based model hsB-SM (hillslope storage Boussinesq Soil Moisture) can improve continuous streamflow simulations for Beaver Creek. Special attention will be paid to remove the above-mentioned bias during wet winter season. The extension of Boussinesq’s equation, which is based on hydraulic groundwater theory, to account for flow convergence in the landscape, as well as the introduction of a dynamic drainable porosity parameter that resolves vadose zone-saturated zone interactions, further enhances the representation of subsurface flow and makes the hsB model more physically based. For all these reasons we expect that hsB-SM will be able to improve wet winter streamflow dynamics in Beaver Creek.
