DEVELOPMENT AND ASSESSMENT OF A GIS BASED MODEL TO IDENTIFY SAND AND GRAVEL RESOURCE POTENTIAL TO ASSIST IN THE ACCELERATION OF AGGREGATE RESOURCE MAPPING BY THE MINNESOTA DEPARTMENT OF NATURAL RESOURCES

The Minnesota Department of Natural Resources (MNDNR) Aggregate Resource Mapping Program (ARMP) was created in 1984 by the MN Legislature Statute 84.94 to protect construction aggregate resources by identifying and classifying potential sand and gravel deposits or crushed stone resources in Minnesota counties. Since 1984, the mapping of 23 counties’ aggregate resource potential has been completed, four projects are near completion or in-progress, and there are 8 counties requesting mapping. As Minnesota’s population continues to grow there is a significant need to accelerate the mapping of construction aggregate resources to assist in their protection. To address the need, a pilot project was set up to develop a geographic information systems (GIS)-based model that identifies the locations of significant and nonsignificant sand and gravel resources based upon ARMP aggregate mapping classifications. The model developed was tested in Carlton County, Minnesota and the Fond du Lac Reservation. The model applied four 10-meter cell grids derived from the following sources, in order of importance: Minnesota Geological Survey (MGS) Surficial Geology (scale 1:100,000), Soil Survey Geographic (SSURGO) database (1:20,000); MGS maintained County Well Index (CWI) stratigraphy database; and identified sand and gravel pits and prospects. The second objective of the project was to determine the validity of the model’s results by completing a raster comparison analysis with the sand and gravel resource potential from the MNDNR’s ARMP map publication, “Aggregate Resources of Carlton County and Fond du Lac Reservation.” A comparative 10-meter raster analysis was chosen and displayed the final modeled cells equaling 93 percent of the published ARMP map source cells. More specifically, the final model equaled 94 percent of the nonsignificant potential ARMP cells, and 66 percent of the significant potential cells. It is important to note that ARMP’s significant potential map units only equaled 4.5 percent of the total study area while nonsignificant potential equaled 95.5 percent. The GIS model proved to be an effective tool at modeling sand and gravel resource potential. It is best utilized by ARMP geologists as an interpretive tool to map counties more efficiently.