The 30-site network was designed to represent a subarea of the Allegheny River Basin in the Appalachian Plateau Physiographic Province. The subarea is limited to the sampling the coarse-grained valley-fill aquifers of glaciofluvial origin in the northern part of the ALMN Basin. The network includes four counties in northwestern Pennsylvania and three counties in western New York. The wells were sampled to assess the ground-water quality across the region. The 30 sites were randomly selected from privately owned wells used to supply water to homes and businesses. This sampling is termed a Study-Unit Survey for the NAWQA Program. Field constituents were measured and water samples collected for laboratory analysis of nutrients, major ions, pesticides and volatile organic compounds (VOC's).
The shaded part of the figure shown below shows the sampling subarea and well sample locations in the glaciofluvial sediments of the Appalachian Plateau Physiographic Province: