Digital Data for Significant Sand and Gravel Aquifer Maps
Boundaries and Polygons
These datasets contain boundaries and polygons of significant sand and gravel aquifers (glacial deposits that are a significant ground water resource) for Maine mapped at a scale of 1:24,000. The Maine Geological Survey used this data to produce Significant Sand and Gravel Aquifers Maps. Aquifer boundaries were delineated and digitized by the Maine Geological Survey from data compiled on USGS 7.5' quadrangle bases. Aquifer polygons are coded by yield expected from a properly constructed well (ATYPE = 0 area not mapped as aquifer; ATYPE = 1 10-50 gallons-per-minute; ATYPE = 2 greater than 50 gallons-per-minute; ATYPE = 3 island of non-aquifer material within an area mapped as aquifer).
Aquifer boundaries were delineated based in part on the surficial materials dataset. The Maine Geological Survey used this data to produce Surficial Materials Maps. This dataset contains point data describing the textures of surficial sediments, independent of interpretations regarding their origin, mapped at a scale of 1;24,000. Thickness of gravel, sand, silt, clay, and diamicton is shown. Data comes from auger holes, test pits, well logs, test borings, and gravel pits. Point data was compiled and digitized by the Maine Geological Survey from data compiled on USGS 7.5' quadrangle bases. The point attribute table contains information on the type of data point and, where appropriate, depth to bedrock, depth to water table, well yield, and/or material type and thickness.
Seismic line data were also used to help delineate aquifer boundaries. This dataset contains line data describing the results of 1-channel and 12-channel seismic refraction studies mapped at a scale of 1:24,000. The results include the depth to the water and depth to the bedrock.
The digital data may not include information from the most recently published significant aquifers and surficial materials maps. This data will be updated periodically but may be out of step briefly with published maps. The user should check the source attributes associated with the significant aquifers data (points/lines/polygons) and verify that the digital data reflects the current published map for the quadrangle. The user can view the most recently published maps or check the source for the cited open-file map in the Bibliography of Maine Geology by searching for the open-file number (e.g. 04-93) in the keyword search source field.
Instructions for Downloading Digital Significant Aquifers Data
- Using a web browser, go to the Maine Office of GIS Data Catalog. A topical listing of digital data layers will appear. Scroll down to the section titled Geological and geophysical.
- For aquifer boundaries, choose the data layer named Aquifer contacts.
- For aquifer polygons, choose the data layer named Aquifer polygons.
- For supporting point data, choose the data layer named Surficial materials data.
- For supporting seismic line data, choose the data layer named Seismic lines.
- Click on the icons in the appropriate "Download" column to:
- View metadata.
- Download a .zip file of the shapefile.
- Download a .kmz file to view the data using Google Earth.
Last updated on November 9, 2012