DERIVATIVE ON-DEMAND GIS PRODUCTS FROM BEDROCK AND SURFICIAL GEOLOGICAL MAPS

The New Hampshire Geological Survey (NHGS) has been systematically mapping bedrock and surficial geology on a quadrangle-by-quadrangle basis under the U.S. Geological Survey National Cooperative Geologic Mapping Program (STATEMAP) and cooperatively with academic partners (EDMAP). To date, 43 percent of the surficial geology of the state has been completed at a scale of 1:24,000. Detailed bedrock coverage is being upgraded to this scale through new mapping which supersedes previously published 1:62,500-scale maps. Additionally, the NHGS maintains databases for hydrography, subsurface data, and water wells, that can easily be merged with interactive, on-line GIS sources such as New Hampshire GRANIT and Geodata.Gov.

The NHGS routinely processes requests for geologic information from the public sector (federal, state, and local governments and agencies), private sector (business, industry, groups, and individuals), and academic institutions. Examples of the diversity of requests are presented whereby geologic maps in GIS digital format have been accessed to produce on-demand derivative maps meeting specific needs of the users, such as resource management, environmental impact assessments, construction planning, cartography, and scientific investigations. During the last two years the NHGS has studied several significant fluvial events, including a major avulsion in southeastern New Hampshire and catastrophic flooding in the southwestern part of the state. In these cases derivative maps combined lithologic, structural, and hydrographic GIS layers in order to understand the mechanics of the events. Other derivative maps included bedrock-map coverage for the contributing drainage basins to Newfound Lake (for resource and water-quality management), geologic hazard assessment for upgrades at two facilities of a gas pipeline, baseline geologic data for a potential site for a potential major new industrial plant, fault and bedrock maps for a town in southeastern part of the state for the USGS, and a geologic map for a potential US Army Corps of Engineers geothermal project in southeastern New Hampshire.