In 1986 the Arizona Legislature established the first program to allow storage of renewable water underground and recovery at a later time. During the next few years, the Legislature added several other programs related to underground water storage. The UWS program has two sets of goals. The first set of goals is to encourage the use of renewable water supplies to satisfy existing needs, to allow for effective and flexible storage of renewable water supplies not currently needed, and to preserve non-renewable groundwater supplies. The UWS program, consistent with the Arizona Groundwater Management Act of 1980, encourages the direct use of renewable water over the use of non-renewable groundwater.
Renewable water is generally surface water that comes from precipitation and municipal effluent.
In contrast, non-renewable groundwater is relatively finite and is resupplied slowly, if at all. The second set of goals facilitates the efficient and cost-effective management of water supplies by allowing storage of water in one location and recovery in a different location. The recipient then uses the renewable water in lieu of groundwater. The potential for increasing the number of GSF projects is limited by the amount of agricultural land in the Active Management Areas. As agricultural land is taken out of production due to urbanization or other factors, the acreage available for this type of project decreases.