Development and vegetation removal on or near bluffs and steep slopes often results in erosion, slope failure, landslides, and visual impacts to these sensitive natural features. The interaction of geologic and hydrologic factors affect bluff and slope stability. Geological factors include bedrock type and location, soil type, slope angle. Hydrological factors include the quality of vegetation cover, intensity and duration of precipitation, and the presence of springs. Land development and land alteration change the way water moves across and through the land and along with increased frequency and intensity of rainfall can increase risks.
Professional inventories and studies can help communities better assess failure risk, so they can put appropriate measures in place to ensure future development is safe and does not increase risk. To learn what other communities are doing and available resources, see:
Strategies for Reducing Risk of Slope Failure
Strategies for reducing the risk of slope failure vary depending on local risk factors. General approaches include:
- Avoid land disturbances on or near slopes to minimize slope erosion
- Establish and maintain vegetation that helps stabilize slopes
- Avoid the placement of stormwater treatment facilities or septic drainfields on slopes or near the top of slopes
- Regulate the placement of structures and land alterations in bluff and steep slope areas
- Using erosion-control and stormwater management measures to reduce erosion and overland flow
- Public education and outreach
Desktop Methods for Identifying Bluffs and Steep Slopes
The following methods use LiDAR-based elevation data to identify where steep slopes may exist. These resources are for preliminary evaluations and planning purposes. An on-site survey is recommended for regulatory and building purposes.
- Use MNTOPO. To quickly evaluate specific sites, please see the tutorial Identifying Bluffs and Steep Slopes with MnTOPO.
- To evaluate a larger geographic area using ArcMap, download the DNR Bluff Mapping Tool a GIS-based add-on available on the Minnesota Geospatial Commons.