The major goal of Thrust Area 1 is to measure, estimate and model the spatial and temporal components of the basin-scale water balance (snow accumulation, distribution, and melt, rainfall, evapotranspiration/sublimation, runoff, and infiltration) by intensive and continuous field observations, coupled with modeling, in areas above the mountain front and a variety of ecological locations on the desert floor.

There are four focus areas within TA1. All four research areas are linked by the common goal of trying to understand the components of the water balance across a catchment area and are differentiated by location and scale:

• 1.1 Environmental Water Balance above the Mountain Front
  
  
• 1.2 Runoff and Infiltration in Semi-Arid Regions
  
  
• 1.3 Remote Sensing and Modeling of Precipitation
  
  
• 1.4 Hydrologic Modeling of Headwater Basins