Sand and Gravel Aquifer Mapping

Types of Aquifers

Subsurface water that fills the spaces between particles of rock and soil, or in fractures in solid rock, is called ground water. An aquifer is a subsurface water supply which yields useful quantities of ground water to wells and springs. There are two types of aquifers in Maine: surficial materials and fractured bedrock. In unconsolidated surficial deposits the water fills the pore spaces between the rock fragments that make up the deposits. Coarse-grained surficial materials such as sand and gravel are capable of transmitting large quantities of ground water and are generally the most productive ground water resources in the State.

Uses of Aquifer Information

When deciding where to locate a domestic or municipal well, aquifer information is very important. Information such as high yield zones in bedrock and the location of sand and gravel aquifers can influence where a well driller locates a well, and what type of well is constructed. Knowledge of aquifers and their recharge areas is also critical when siting possible sources of pollution such as landfills, salt piles, and hazardous wastes. Aquifer maps and texts from the Maine Geological Survey contain information on aquifer favorability and vulnerability and are widely used by local and state officials in making environmentally sound siting decisions, and by well drillers, developers, and geological consultants as a base for detailed hydrogeological studies.

Sand and Gravel Aquifer Mapping in Maine

Investigations conducted from 1978 through 1980 resulted in the production of 59 Sand and Gravel Aquifer Maps at a scale of 1:50,000. These maps delineated approximate aquifer boundaries, potential well yields, and potential point sources of contamination. To satisfy the demand for more accurate, complete, and current hydrogeologic information concerning sand and gravel aquifers in Maine, the Significant Sand and Gravel Aquifer Map series was initiated in 1981. From 1981 through 1986, more detailed maps for the study areas were published at a scale of 1:50,000. Beginning with the 1987-88 study area and for subsequent years, the maps were published at a scale of 1:24,000.

In 1995 the Maine Geological Survey began a program to upgrade all 1:50,000-scale Significant Aquifer Maps to an improved scale of 1:24,000. Work began by digitizing existing map and subsurface data, generating and digitizing new seismic data, and mapping surficial geology to refine existing aquifer boundaries. All of the area covered by the old 1:50,000-scale maps has now been upgraded to 1:24,000 scale.

Last updated on October 6, 2005

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Sand and Gravel Aquifer Mapping

Types of Aquifers

Uses of Aquifer Information

Sand and Gravel Aquifer Mapping in Maine