Protection of New York State 's aquifers has become an increasingly important issue among water resource managers at all levels of State and municipal government. Aquifer delineation is necessary as an initial phase in the effective management of the State 's groundwater resources. As part of an effort to delineate all major unconsolidated aquifers in New York, a cooperative study was conducted to compile a groundwater availability map that would complete the reconnaissance mapping of the mid-Hudson River basin at a scale of 1:250,000. This map delineates the principal unconsolidated aquifers in the mid-Hudson River basin area and the estimated potential yield of properly constructed wells completed in these aquifers. (Lantz-PTT)