Southern Red River Valley, Minnesota Regional Hydrogeologic Assessment, Part B

• Lineage

• A file of depth-to-water readings for several locations in the Southern Red River Study Area was kriged in Surfer, creating a grid file of interpolated readings every 1000 meters.
• This file was converted into a DBF file in Excel, made into an "event theme" in Arcview, converted into a shapefile, then into an ARC/INFO coverage.
• The coverage was converted into a TIN with the ARC command 'arctin,' then the TIN was contoured with the ARC command 'tincontour' with a 10-foot contour interval.
• The resulting contour coverage was combined with the study area boundary with the ARC 'union' command, and built as a polygon coverage.
• The labels from the polygons were given depth-to-water values by overlaying them with a depth-to-water lattice (made by applying the ARC command 'tinlattice' to the depth-to-water TIN explained above), and interpolating a single depth-to-water value from several depth-to-water values on the lattice that are in the immediate proximity of each label point on the lattice. The ARC command 'latticespot' does this. This gives each polygon label a depth-to-water value, but each polygon actually represents a range of values, because it comprises the entire area between 10 foot contour lines.
• Polygon labels with a depth-to-water value of less than 10 were given a range value of 1 ( less than 10 feet). Polygon labels with a depth-to-water value of greater than 10 and less than 20 are given a range value of 2 (10 to 20 feet), etc. See Entity and Attribute Information, below.

Users may wish to verify critical information; sources include both the references here and information on file in the offices of the Minnesota Geological Survey and the Department of Natural Resources. Every effort has been made to ensure the interpretation shown conforms to sound geologic and cartographic principles. This map should not be used to establish legal title, boundaries, or locations of improvements.