RHAs are larger areas (typically 4-9 counties) that are covered in less detail than a county atlas. These include areas in the Anoka Sand Plain, Southwestern Minnesota, Southern Red River Valley, Upper Minnesota River Basin, Otter Tail, and Traverse-Grant. These are older assessments that will be replaced by the County Geologic Atlases as they are completed.
Anoka Sand Plain RHA-1
Included Counties: Anoka, Chisago, Isanti, and Sherburne
1993, Minnesota Department of Natural Resources
- PDF and GIS files
- Plate 1 - Surficial geology (3.16 MB)
- Plate 2 - Water-table hydrogeology and water well data base distribution (2.54 MB)
- Plate 3 - Sensitivity of the water-table system to pollution (1.71 MB).
Southwestern Minnesota RHA-2
Included Counties: Murray, Nobles, Pipestone, and Rock; and parts of Cottonwood, Jackson, Lincoln, Lyon, and Redwood
Part A - Geology, 1995, Minnesota Geological Survey
- PDF and GIS files: Plate 1 - Surficial geology and Plate 2 - Quaternary stratigraphy
- Report of Investigations 47 - Contributions to the Quaternary geology of southwestern Minnesota.
Part B - Hydrogeology, 1997, Minnesota Department of Natural Resources
- Plate 3 - Surficial hydrogeology (6.4 MB)
- Plate 4 - Sensitivity of surficial aquifers to pollution (2.2 MB)
- GIS files
Southern Red River Valley RHA-3
Included Counties: Clay, Norman, and Wilkin; and parts of Becker, Grant, Mahnomen, Otter Tail, Stevens, and Traverse
Part A - Geology, 1995, Minnesota Geological Survey
- PDF and GIS files Plate 1 - Surficial geology and Plate 2 - Quaternary stratigraphy
Part B - Hydrogeology, 2000, Minnesota Department of Natural Resources
- Plate 3 - Surficial hydrogeology (1.3 MB)
- Plate 4 - Sensitivity of surficial aquifers to pollution (1.8 MB)
- GIS files
Upper Minnesota River Basin RHA-4
Included Counties: Swift, Chippewa, Lac qui Parle, and Yellow Medicine; and parts of Big Stone, Lincoln, Lyon, Redwood, and Renville
Part A - Geology, 1999, Minnesota Geological Survey
- PDF and GIS files: Plate 1 - Surficial geology and Plate 2 - Quaternary stratigraphy
Part B - Hydrogeology, 2000, Minnesota Department of Natural Resources
- Plate 3 - Surficial hydrogeology (980 KB)
- Plate 4 - Geologic sensitivity to pollution of near-surface ground water (1.18 MB)
- GIS files
Otter Tail RHA-5
Included Counties: parts of Becker, Douglas, Grant, Hubbard, Otter Tail, Todd, and Wadena
Part A - Geology, 1999, Minnesota Geological Survey
- PDF and GIS files: Plate 1 - Surficial geology and Plate 2 - Quaternary stratigraphy
Part B - Hydrogeology, 2002, Minnesota Department of Natural Resources
- Plate 3 - Surficial hydrogeology (2.0 MB)
- Plate 4 - Geologic sensitivity to pollution of near-surface ground water(4.6 MB)
- Technical Appendix - Appendix - Water chemistry and residence time (2.8 MB)
- GIS files
Traverse-Grant RHA-6
Included Counties: Pope and Stevens; and parts of Big Stone, Douglas, Grant, Traverse
Part A - Geology, 2006, Minnesota Geological Survey
- PDF and GIS files: Plate 1 - Surficial geology and Plate 2 - Quaternary stratigraphy
Part B - Hydrogeology, 2008, Minnesota Department of Natural Resources