Streamflow, recharge, and groundwater are crucial components of the water cycle which contribute to sustaining ecosystem needs, and economic and social development. These components are, however, highly dynamic, being sensitive to both climatic and watershed physical characteristics. The objective of this doctoral research is to examines how subsurface characteristics control catchment streamflow, recharge, and groundwater response to climate change across a gradient of snowmelt-dominant watersheds in the Yakima River Basin in central Washington. A sensitivity analysis framework consisting of the Distributed Evaluation of Local Sensitivity Analysis (DELSA), a physically based hydro-ecological model (Regional Hydro-Ecologic Simulation System, RHESSys) and a groundwater model (Modular Three-Dimensional Finite-Difference Groundwater Flow Model, MODFLOW) is used. First, this dissertation finds that streamflow sensitivity to parameter uncertainty changes depending on the parameter ranges. It also shows that the governing streamflow generation processes that are mostly sensitive to parameter uncertainty for given climatic, and subsurface properties as well as flow conditions in each watershed vary as parameter ranges change. Second, results show that precipitation ([epsilon]P) and temperature ([epsilon]T) elasticities of streamflow and recharge are greater and vary in wider ranges in the drier catchment with less permeable soil than in the two wetter catchments with more conductive soil. Moreover, responses of [epsilon]P and [epsilon]T of streamflow and recharge to temperature perturbation are more nonlinear and are often in the opposite direction of the responses to precipitation perturbation. Soil transmissivity is the most influential catchment physical characteristic governing [epsilon]P and [epsilon]T of streamflow and recharge. Under altered climate conditions, the relative importance of subsurface properties in governing streamflow and recharge elasticities do not dramatically change but vary depending on the warming/cooling or wetting/drying directions as well as the catchment physical properties. Finally, horizontal hydraulic conductivity of the upper aquifer in the Roslyn formation is the dominant parameter controlling groundwater head in four layers in the wettest watershed. In another wetter watershed, the groundwater head response is controlled by the horizontal hydraulic conductivity of the Grande Ronde interflow zone.