USING GIS TO INVENTORY COMMON VARIETY MINERAL MATERIALS FOR THE HURON-MANISTEE NATIONAL FOREST, MI

The Huron-Manistee National Forest (HMNF) is relatively well endowed with aggregate resources such as gravel, sand, clay, boulders and stone. These common variety mineral materials are useful to the HMNF for projects such as road repairs, stream crossings, trail maintenance, and canoe landing sites. The development of aggregate resources on Federal lands of the HMNF has been a decreasing priority in recent decades. Since the 1980’s, an increasing number of Forest Service pits have been closed and reclaimed, in favor of more ecologically and aesthetically pleasing land management practices. Fragmented land and mineral ownership patterns within the HMNF proclamation boundary also hinder the development and management of mineral material pits. For these reasons, there has been an increase in the number of commercial pits in the surrounding area, from which the HMNF now purchases aggregate resources to complete construction, maintenance, and engineering projects. The increasing reliance on commercial aggregate suppliers throughout the years has resulted in a fragmentation of knowledge about the distribution and quality of common variety minerals on HMNF lands. Information about the location of quality aggregate resources has become somewhat antiquated and often occurs in dispersed file cabinets or as informal knowledge in the minds of District personnel. At this time, it is unclear whether it makes more economic sense to extract these materials from NFS lands, or continue purchasing aggregate from commercial suppliers. Moreover, there are no detailed geologic maps covering the HMNF at this time, which adds an additional level of uncertainty about the quality and quantity of aggregate resources at depth. Since 2011, the HMNF has utilized the GeoCorps America program to put intern geoscientists to work on assimilating data and information about common variety minerals on Forest Service lands. This information is currently being gathered and stored in an ArcGIS geodatabase. When complete, the geodatabase will serve as a useful tool for project planning, and advance the ongoing effort to inventory common variety minerals across the HMNF. This presentation will highlight the methods used to inventory and map historic and existing pits, as well as discuss practical uses of the geodatabase for HMNF land managers.