The U.S. Geological Survey (USGS), in cooperation with the New Hampshire Department of Environmental Services (NHDES), estimated water demand, consumptive use, withdrawal, and return flow (components of water use) for each U.S. Census block in New Hampshire for the years 2005 and 2020. The estimates are for both registered and unregistered use, including domestic (household), irrigation, industrial, and commercial use. Data collected and generated are stored in the project's New Hampshire Water Demand database. The results for the small geographic areas of census blocks may be aggregated to larger political areas or watersheds to assess relative stress on the basis of current and potential water availability.
The water-use estimates were derived through the use and innovative integration of several databases (WATUSE, Drinking Water, NPDES, Census, and Population Estimates databases) obtained from state and federal sources, in conjunction with previously developed techniques during the New Hampshire Seacoast water use study. Water users common to more than one database were identified, and a 'lookup' table was created in order to link these databases and identify withdrawal and return-flow locations of registered and unregistered commercial, industrial, agricultural, and other non-domestic users. Geographic Information System (GIS) data from the NHDES were used in combination with U.S. Census Bureau spatial data to locate and quantify withdrawals and return flow for domestic users in each census block.
Analyzing and processing the data resulted in census-block estimations of 2005 water use. Applying population projections developed by the State to the data sets enabled projection of water use for the year 2020. The methods used to develop these statewide water-use estimates are described in a USGS report that will be available in 2009. Data from the project showing estimated domestic withdrawal and return flow, registered withdrawal and return flow, and unregistered (community and non-community) withdrawal and return flow for 2005 and 2020 will be available to the public once the project and report are finalized in 2009. These data will be integrated into a statewide study assessing hydrologic stress on streams and part of the New Hampshire Water Resources Plan Process.
Summaries and 2005 estimates aggreggated by county, town, and watershed are now available on the NH-VT Water Use Estimates for 2005 web site.