Glacial Aquifer System - Hydrogeologic Properties

Science Center Objects

Water-well drillers’ records are used to create maps and grids of hydrogeologic properties for the glaciated United States.

Background

  • Water-well drillers’ records are a prolific source of hydrogeologic information
  • Most states maintain databases of well-drillers’ records
  • Digital datasets have a wide range of applications

Study Area

Map of the glacial aquifers study area

 Maps and Grids of Hydrogeologic Information

Maps and grids of hydrogeologic information have a wide range of applications. Maps provide visual information about resources. Grids can be used in a variety of analyses. Examples of applications for this information include groundwater flow and transport models,  statistical models, resource availability and accessibility estimates, and low-flow computations for ungaged streams.

Approach

More than 11 million water-well records from state agencies were used to create grids and maps of hydrogeologic properties for most of the glaciated United States (U.S.). Records missing information were removed from the dataset. Drillers’ geologic descriptions  were converted into terms supported by the U.S. Geological Survey’s Ground Water Site Inventory database.

Products

Maps and grids created by this study include:

  • texture-based estimates of equivalent horizontal and vertical hydraulic conductivity
  • texture-based estimates of transmissivity
  • specific-capacity-based hydraulic conductivity and transmissivity
  • thickness of glacial deposits
  • total thickness of coarse-grained deposits
  • bedrock surface lithology
  • bedrock surface altitude

Maps were compared with the literature to insure reasonable interpretations of the water-well records. The processes used to create the maps and grids are documented in USGS Scientific Investigations Reports.

Partners

U.S. Geological Survey – Water Availability and Use Science Program

U.S. Geological Survey – National Water Quality Program

25 State government agencies