VERMONT GEOLOGICAL SURVEY: BASE SCIENCE FOR HEALTH, SAFETY, AND WELFARE

The Vermont Geological Survey (VGS), in a dynamic response for continued relevance, produces framework geologic maps and employs this information for the protection of public health and safety while supporting the general welfare. Base science is the root of VGS public service framework and derivative maps. VGS maps are outputs in the strategic planning sense but are designed to reach outcomes that serve the State and local communities.

VGS is working toward a new State bedrock geologic map in cooperation with USGS and is mapping bedrock and surficial geology by watershed, town, or quadrangle boundaries. Pilot ground water resource planning maps integrate located water well and boring data with base geology. Information release concerning naturally-occurring constituents of concern such as uranium, radium, radon, and arsenic is coordinated with the VT Dept. of Health as a tool for mitigation. Erosion hazard maps focus on rock falls and landslide/debris flow data integrated with fluvial geomorphic information. Seismic risk and slope instability analyses support Vermont emergency management goals. Nitrates in domestic wells next to a large farm are under study in cooperation with the VT Agency of Agriculture. Earth and water resources data advance economic development.

Protection of the public health and welfare is an outcome reached in the Town of Williston, VT. Median values of located water well parameters confirm anecdotal reports of low yields. Selected areas of calculated average well yield over the Fairfield Pond and Pinnacle Formations give a general sense of the most difficult areas for obtaining adequate supply. The Town used VGS maps in the review of a development proposal. They required a pump test, the tested yield proved inadequate to meet projected demand, and the developer withdrew the proposal.

Radiometric studies in the Towns of Milton and Colchester identified general areas of elevated radioactivity within the Clarendon Springs Formation (CSF). Geologic mapping and additional radiometric analyses were conducted on wells within/in close proximity to the CSF. 28 of 29 wells were identified in the CSF that exceeded EPA gross alpha standards. These data were used to derive a radionuclide “hazard” map for use by Town Health Officers to assist homeowners with domestic water supply decision-making.