Long-term Changes to Hydrology and Sediment Transport due to Climate Variability in Southern California Watersheds

This study focuses on assessing regional-scale, long-term impacts of future climate variability on water resources and water quality in southern California. Specifically, this work includes evaluating the product of statistically downscaled meteorological inputs on sediment transport and hydrologic flux in a range of watersheds with varying urban development and geomorphologic properties. The downscaling method utilized the CNRM-CM3 GCM model and a newly developed downscaling approach using canonical correlation analysis to obtain daily precipitation and temperature measurements for the Greater Los Angeles Region. The three data periods modeled include historic (1961 - 2000), near-term climate periods (FC1, 2046 - 2065) and longer-term climate periods (FC2, 2081 - 2100). Future climate simulations used the high (A2) and low (B1) emission scenarios, as defined by the IPCC. The downscaled data were used as inputs for the Environmental Protection Agency's Hydrologic Simulation Program—Fortran (EPA HSPF) model to ultimately evaluate differences in historical and future hydrologic fluxes. The initial phase of our work focuses on simulations and comparative analysis for three distinct regional watersheds, Ballona Creek, Malibu Creek and Arroyo Seco, respectively.