Resolving Spatiotemporal Climate Change Impacts on San Joaquin Basin Hydrology

Abstract:

Predicted changes to California’s climate over the coming decades are expected to affect distribution, timing, and type of precipitation. This shift in timing and amount of water, particularly that originating from mountain sources, will affect the hydrology of the intensively farmed Central Valley and reliability of supply for growing urban areas on the coast and in the valley. Previous studies have assessed potential impacts of future climate scenarios on Sierra mountain and central valley hydrology through GCM-LSM coupling as well as lumped and semi-distributed hydrologic models. However, little work has been done to simulate the propagation of potential climate change impacts through the full hydrologic system at a refined spatial and temporal resolution in a manner that fully captures the mechanistic interconnection between the surface and subsurface. The integrated hydrologic model ParFlow, coupled with the land surface model CLM, is used in this study to evaluate the impact of changed climate scenarios (derived from CMIP5 datasets) over the San Joaquin basin in central California at 1 km horizontal resolution. Simulation results allow diagnosis of impacts to critical water budget components including streamflow, groundwater-surface water exchange, and valley recharge.