Regional Hydrogeologic Assessment (RHA)

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.

Minnesota map of hydrogeologic assessment areas
 

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 

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

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

  • Plate 3 - Hydrogeology of the Surficial and Buried Aquifers (6.6 MB)
  • Plate 4 - Depth and Thickness of Buried Aquifers (11 MB)
  • Plate 5 - Hydrogeologic Cross Sections (1.9 MB)
  • Plate 6 - Sensitivity to Pollution of the Buried Aquifers (7.1 MB)
  • GIS files

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