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County geologic atlases provide information essential to sustainable management of ground water resources, for applications such as monitoring, water allocation, permitting, remediation, and well construction. They define aquifer properties and boundaries, as well as the connection of aquifers to the land surface and to surface water resources. They also provide a broad range of information on county geology, mineral resources (including construction materials), and natural history.

A complete atlas consists of a Part A prepared by Minnesota Geological Survey (MGS) that includes the water well database and 1:100,000 scale geologic maps showing properties and distribution of sediments and rocks in the subsurface, and a Part B constructed by the Department of Natural Resources (DNR) that includes maps of water levels in aquifers, direction of groundwater flow, water chemistry, and sensitivity to pollution. Atlases are usually initiated by a request from a county and an offer to co-fund or provide in-kind service. MGS is committed to the expeditious completion and periodic updating of atlases statewide.

GEOLOGIC ATLAS USER'S GUIDE is a document intended for people that don’t have training in geology or hydrology. Every Minnesotan uses water, and every Minnesotan has an effect on water, so we all have a role and an interest in how that resource is distributed, how it is used, and how we affect its quality and availability. The purpose of this Guide is to explain, through reference to County Geologic Atlas products, where our water comes from, how geology and climate control its distribution, and how we can manage water to maximize its availability at the highest quality.

On the map below, (Left) Click once on a county to see more information and links to PDFs and digital data. If the pop-up box is partially hidden, maximize it with the left icon in the upper right corner. Older Atlases only have PDF images available. Newer mapping is generally available in digital format. To see what is available, examine the footprint maps.

Atlases begin with compilation of a database of subsurface information. The most abundant data source is the construction records of water wells. With the cooperation of the County, accurate digital locations are established for these wells to support their use in mapping. Concurrently, geologists visit the project area to describe and sample landforms and exposures of rock or sediment. An initial assessment of the geologic data is then completed to focus additional data gathering including shallow and deep drilling programs. Analysis of the complete data set is then completed, and maps and associated databases are prepared for use in geographic information systems (GIS) and distribution via DVD and the web. Most of the products are also printed for the benefit of users who prefer this format. GIS files are available for atlases beginning with C-7. Scott County has been revised, so the original C-1 maps are available as scans, while the C-17 revision is available with GIS files.