TOWARDS DESIGN OF A LANDSLIDE INVENTORY GEODATABASE FOR MINNESOTA

Landslide inventories are instrumental for characterizing regional landslide hazards. In the post-glacial landscapes of Minnesota, steep slopes result from prior glacial events including meltwater flows that carved deep valleys through glacial sediments and bedrock and from tributary systems still actively incising in response to the formation of these deep valleys. Heavy precipitation events can result in soil saturation, runoff, and flooding, which often trigger slope failures in Minnesota. To characterize and reduce risk from slope failures, we created a GIS (Geographic Information Systems) inventory to analyze and better understand landslide occurrence. Following geodatabase protocols developed in the states of Washington and Oregon, we designed a geodatabase to map and describe areas of past slope failures across five landslide-prone regions in the state. The geodatabase design was iteratively modified and adapted after feedback from and communication among the various researchers creating the inventory. The geodatabase was used to catalog and organize the features and attributes necessary to characterize slope failures for different parts of the state. Landslides were mapped with unique IDs based on their location within the USNG (United States National Grid) system for Minnesota. Geodatabase attribute domains were used to describe mapped features in a way that kept descriptions uniform across all contributors so that one can filter and sort the database for specific types of landslide features. Geodatabase relationship classes were designed to relate mapped features to one another, such as characterizing the relationships among multiple headscarps and slope failures that feed coalesced deposits or other complex geomorphic relations. This collaborative, nearly statewide landslide inventory project benefited from careful geodatabase version control and management. Ultimately, a uniform geodatabase design will aid in landslide susceptibility analyses across Minnesota and can be adapted for work elsewhere.