A growing list of research + code + experiments.
Uncertainty in future climate projections presents a major challenge for water resource planning, particularly in continental and semi-arid watersheds where small hydroclimatic changes can lead to disproportionate impacts on water availability. This study evaluates the suitability of the LOCA2 downscaled CMIP6 climate ensemble for basin-scale water budget applications through a two-stage validation approach. First, LOCA2 historical simulations are compared against nClimDiv observational climatologies across multiple 30-year periods (1951–2014). Second, a Thornthwaite-Mather water balance framework with explicit snowpack dynamics is calibrated against USGS streamflow observations to determine optimal soil storage parameters. Validation across three contrasting HUC08 basins, representing semi-arid (South Dakota), humid (Vermont), and arid (New Mexico) environments, demonstrates strong model performance in unregulated basins, while flow regulation from Navajo Reservoir limits validation in the San Juan-Chaco basin; supplemental analysis using NLDAS forcing data is explored to further characterize this limitation. LOCA2 reproduces key hydroclimatic signals at basin scales, and calibrated parameters are applied to project future water availability under SSP2-4.5 and SSP5-8.5 scenarios. This approach provides a computationally efficient method for translating probabilistic climate projections into actionable water budget information, supporting climate-resilient water management in data-sparse regions serving disadvantaged communities.