Objective Explore the nature of the subsurface flow generation process and its controlling factors

1. Regionalization of Subsurface Stormflow Parameters of Hydrologic Models: Derivation from Regional Analysis of Streamflow Recession Curves • Objective • Explore the nature of the subsurface flow generation process and its controlling factors • Develop an empirical relationship that could be used in subsurface flow estimation without calibration • Approach • Calculated the coefficients related to subsurface flow generation process from flow data; extracted the climate, soil and topographic characteristics from several online databases for 50 selected catchments in the U.S. • Using a variable selection scheme to identify the most important controlling factors that determine the observed flow decay behaviors and validating the empirical relationship using data Comparison of observed and fitted streamflow time series in a well-measured catchment in the U.S. • Impact • Found that one of the coefficients in the empirical relationship is closely related to the catchment hydrologic properties, while the other one is more strongly affected by climate (aridity) at the catchment scale. • The climate dependence may be attributed to the adaption of landscape properties (e.g., soil, vegetation and topography) to climate at the catchment scale Ye S, H-Y Li, M Huang, M Ali, G Leng, LR Leung, S Wang, M Sivapalan. 2014. “Regionalization of Subsurface Stormflow Parameters of Hydrologic Models: Derivation from Regional Analysis of Streamflow Recession Curves.” Journal of Hydrology, early online. DOI: 10.1016/j.jhydrol.2014.07.017