Identifying climate change impacts on surface water supply in the southern Central Valley, California

Mountain regions in arid and semi-arid climates, such as California, are considered particularly sensitive to climate change because global warming is expected alter snowpack storage related surface water supply. It therefore important accurately capture snowmelt processes watershed models for impact assessment. In this study we use the Soil Water Assessment Tool (SWAT) estimate projected changes streamflow four alpine tributaries agriculturally but less studied southern Central Valley, California. Watershed responses evaluated CMIP5 (HadGEM_ES, CNRM-CM5, CanESM2 MIROC5) two emission scenarios (RCP 4.5 RCP 8.5) 2020–2099. SWAT calibrated following a dual-objective, lumped calibration approach with an automatic against observed (stage 1) manual reconstructed Parallel Energy Balance (ParBal) snow equivalent (SWE) data 2). Results indicate that under climate, peak increase 0.5–4 times magnitude coming decades arrive 2–4 months earlier year of snowmelt. foreseeable future, cover will reduce gradually lower elevations diminish at higher rates elevation towards end 21st century. Surface supply predicted Valley increased temporal variability (wetter wet seasons drier dry seasons) create new challenges managing The further highlights remote sensing based, SWE could fill current gap limited in-situ observations improve better predict impacts semi-arid, snow-dominated watersheds.