Water Availability can be defined as "The hydrologic capacity of a water source (surface water body, groundwater, municipal water) to sustain additional water demands after considering other current water uses and water conditions. (GEMI, 2012)
The Soil Moisture Active Passive Mission provides information on water availability and environmental stress for estimating plant productivity and potential yield. The availability of direct observations of soil moisture status and the timing and extent of potential frost damage from SMAP enables significant improvements in operational crop productivity and water stress information systems by providing realistic soil moisture and freeze/thaw observations as inputs for agricultural prediction models. Improved models provide crucial information for decision-makers managing water and other resources, especially in data-sparse regions.
Even without simulation models, farmers can also use soil moisture and freeze/thaw information directly as a proxy for field readiness (i.e., determining when the soil is dry enough for driving heavy machinery). At the global scale, a better grasp of the impact of agricultural drought on crop yield provides better crop supply and demand information for use by producers, commodity markets, traders, and policy makers. Forecasts of the impact of climate fluctuations on crop yields with on-going measurements of soil moisture and freeze-thaw improve management of agriculturally-important pests and disease in developing countries.
Water availability is a high-level, global issue that drives agriculture and has crucial impacts to the global economy.