||A observational and modeling field experiment focusing on the coupled atmospheric, surface hydrology and subsurface hydrology issues in the Black Hills region of South Dakota and Wyoming. Objectives: 1. Assess the importance of deep groundwater in subsurface aquifers to water budgets and water resources in the GCIP LSA-NW. 2. Determine the resolution required in atmospheric and coupled models to represent adequately precipitation and other components of the water budget in orographic terrain. Examine sensitivities and important spatial scales for impacts due to variations is evapotranspiration and moisture advection. 3. Determine the uncertainties in atmospheric components of water budgets on ISA and larger scales in orographic terrain.