Benton County Geologic Atlas

geologicatlasRecently the Minnesota DNR Division of Ecological and Water Resources released the Geologic Atlas of Benton County Part B report. County Geologic Atlases are created as part of a joint program between the DNR Waters and Minnesota Geological Survey (MGS).


A County Geologic Atlas is a systematic, two-part study of a county’s geologic (e.g., rock, sands, and tills) and hydrogeologic (i.e., relating to water and water flow) resources; the Part A report is a scientific study of the geologic materials and the Part B report describes how water flows through the geologic materials. Together, the two reports provide comprehensive data that tells the story of a county's geologic history, formations, groundwater flow systems, aquifer capacity, groundwater chemistry, and sensitivity to pollution. The information is organized, analyzed, and displayed using GIS technology and printed on large format paper maps.


Information published in the County Geologic Atlas is relevant for a wide range of planning and environmental protection efforts at all levels of government—by those who work with groundwater directly or those who work with industries that may use or affect groundwater resources. Source water protection and well sealing programs are examples of local programs that need geologic and groundwater information. Other common uses include providing information for groundwater use permit applications, land use planning and emergency response to contaminant releases. The Part B report provides information also used by businesses (such as well drilling companies) and the general public; at its basic it is a scientific study of the geology and water in your immediate environment.


The Part B report was created using a number of different data sources, including water samples taken from 96 private wells throughout the county as well as information from well driller’s logs and geologist’s stratigraphic interpretations. DNR Waters also utilized the geologic data, maps, and reports prepared by MGS to characterize Benton County’s groundwater hydrology and determine its geologic sensitivity to pollution. Information was gathered describing the presence, direction of flow, and natural quality of groundwater in relation to geology in an effort to manage groundwater resources more effectively.


Program funding came from the DNR Waters budget as appropriated by the legislature. Additional funding from the Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources also supported the project. Beginning in 2010, County Geologic Atlases have been supported by additional funding from the Clean Water Fund.


The Water Resources Advisory Committee (WRAC) is a local citizen group whose mission is to provide coordination between units of government, citizens, and others involved in the protection, management, and improvement of the water resources in Benton County. This group provided input on the project and was instrumental in getting the Part B report completed.


hydrogeologic atlas

Map from the Part B report showing estimated water-table elevation in surficial sediments
with groundwater and surface water flow directions


Free copies of the Part B report can be obtained from the Benton Soil & Water Conservation District in the Foley USDA Office (14 2nd Avenue W.) during normal hours of operation (7:00 am – 4:30 pm). For more information, contact the office by phone at 320-968-5300 ext. 3.


Electronic copies of the atlas can also be obtained by visiting the Benton County Geologic Atlas page. The databases and maps from the Hydrogeologic Atlas will also be produced in digital ArcGIS format so that geographic information system (GIS) tools can be used to update the databases and conduct further analyses. Additional information from DNR Waters staff can be obtained from County Geologic Atlas Supervisor Jan Falteisek (651-259-5665) or Project Hydrogeologist Jeremy Rivord (651-259-5728).