Statewide Groundwater Analyses

Groundwater is an important natural resource in Vermont. A significant percentage of Vermont’s population depends on groundwater for their drinking water supply. Groundwater is also used for manufacturing, agriculture, commercial enterprises, and to support aquatic habitat . Groundwater is dynamic, responding to internal and external conditions. Groundwater quantity and quality varies with climate, precipitation, overlying land use, and the rock and soil types through which it moves. Vermont's geology, characterized by multiply deformed (folded, faulted, fractured) rock and a variety of unconsolidated glacial deposits, is the vessel for Vermont’s groundwater resources. The Survey focuses on mapping bedrock and surficial deposits and obtaining data about this vessel.

Statewide Analyses of Groundwater

In 2008, the Vermont Geological Survey was asked to compile and assess existing datasets related to groundwater in Vermont. Digital datasets used in the study include: 1)1961 Centennial Geologic Map of Vermont (1:250,000 scale), 2) Digital compilation of the 1960-1970 surficial maps of Vermont at scales of 1:24,000 - 1:62,500, 3) Edited and amended Water Supply Division Well Driller database, and 4) Other publically available data such as DEM, soils data, and locations of potential pollution sources. In addition, VT ANR contracted with the USGS to produce a groundwater use study and identify future growth areas. The ANR also contracted a well interference study to evaluate public water supply pump tests and determine any cumulative impact areas. The maps will be posted on this web page as they become available. Planned maps include statewide maps at a scale of 1:250,000 and county maps at a scale of 1:100,000. The Thickness of Overburden in Vermont by Springston et al, 2012, is now on-line. Groundwater favorability maps for surficial materials aquifers are being produced. These maps are using located wells in valley bottoms. Detailed maps (1:24,000 scale) are available where in depth geologic studies have been conducted (see sidebar menu). Hover and click over any map below to see a larger image (pdf file).

Water Well Data
The water well data used in this study is a derivative set of the Vermont Dept. of Environmental Conservation Water Supply Division (WSD) well driller database and includes wells completed between
1961 and April 2008. The location of the data points is from 1) well driller maps and written descriptions, 2) E911 addresses (3100 wells), and 3) GPS measurements (7707 wells). The data includes 4116 wells identified as "gravel" wells and 92,315 other wells. Of the 92,315 wells, most are completed in bedrock, although many have no entry in the "well type" data field. Some corrections were made to the database where numerical errors were obvious and could be reconciled with a driller report. Numerical errors remain in the database. A case study in Brattleboro by ANR IT was completed to test improvement of all well locations by linking to E911 addresses. The study recommended that the VGS continue to use it's current protocols to locate wells by town during detailed mapping projects.

Hover and click over any map below to see a larger image (pdf file). These maps are from: Gale et al., 2009, Statewide Analyses of Bedrock Water Well Data: Vermont Geological Survey Open File Report VG09-8, 7 plates, scale 1:250,000.

DATA SUMMARY, VERMONT WATER WELLS PLATE 1 (13mb pdf)	WELL DATA COMPILED BY BEDROCK UNIT - PLATE 2 (4 mb pdf)	WELL DATA COMPILED BY BEDROCK UNIT - PLATE 3 (2 mb pdf)	BEDROCK UNITS GROUPED BY MEAN WELL YIELD - PLATE 4

BEDROCK UNITS GROUPED BY MEAN WELL DEPTH - PLATE 5	AREAS OF LOWER AND HIGHER YIELD WELLS - PLATE 6	AREAS OF SHALLOWER AND DEEPER WELLS - PLATE 7	THICKNESS OF OVERBURDEN IN VERMONT by Springston et al, 2010