From 1994 to 2002, the U.S. Geological Survey (USGS), in cooperation with the New Hampshire Department of Environmental Services (NHDES), investigated the yields of wells in New Hampshire's bedrock aquifer. This analysis of well yields used a database compiled by the State of New Hampshire, and includes 20,308 accurately located wells with information on yield, depth, and construction. Based on a statistical model, the analysis produced statewide predictions of well-yield probabilities that may be used to assess potential water supplies. The statistical model is documented in the report Factors Related to Well Yield in the Fractured-Bedrock Aquifer of New Hampshire, and a brief overview of the study is available on the "About the Study " page.