ON EVALUATING THE HYDROCLIMATIC SYSTEM IN THE GREAT BASIN

The hydrologic and geochemical cycles in arid regions-hydrologically and topographically closed basins (i.e., Great Basin), are subjected to the climatic variability over a wide range of spatial and temporal scales. Understanding the climate-hydrology interaction in these areas is critical for improving our understanding on past and future climate changes and their impact on hydrology in this region. A coupled catchment-lake model was used to quantitatively estimate paleoclimate (annual precipitation and temperature) in the Owens Valley within the Great Basin. The simulations on lake extent at 18 ka, 15 ka, 12 ka, 9 ka, 6 ka, and modern climate conditions are very compatible with observed or derived data. Derived climate was then used to drive Saturated and Unsaturated Transport (SUTRA) numerical model for simulating subsurface fluid movement and solute transport with rainfall induced recharge from high mountain areas towards the low valley playas of Pilot Valley. The numerical experiments are designed to evaluate how the heterogeneity in geologic formations and spatial variability in topography could affect the groundwater flow and solute transport.