NORTHWEST ARKANSAS LANDSLIDE INVENTORY RESULTS

The Federal Emergency Management Agency (FEMA) Hazard Mitigation Grant Program offers grant funding for federally declared disaster areas. The Office of the State Geologist (OSG) was awarded two Hazard Mitigation Grant Program grants for the purpose of: (1) conducting a landslide inventory in Newton, Madison, and Washington Counties and (2) updating the landslide portion of the All-Hazard Mitigation Plans for Arkansas and for the counties of Newton, Madison, and Washington. Since 2012, landslide road damage has cost the Arkansas Department of Transportation approximately 65 million dollars in repairs for these counties. To slow or prevent more slope failures and further costs, it is important to document and plan for landslides. Over the past 7 years, the OSG has been conducting research on these and other landslides using established protocols. Use of 2017 1- meter LiDAR and ESRI products have been instrumental in the completion of these two grants. Research also encompassed clay mineralogical analysis of geologic strata susceptible to mass wasting. Research findings reveal the size, density, spatial distribution, and slope of the landslides based on established criteria. Since approximately half of the 75 Arkansas counties contain landslides, there is a significant amount of work yet to be done to complete a statewide landslide inventory. With new LiDAR currently being flown, this new imagery will enable more efficient techniques to complete this inventory.