Bluff and Slope Protections

boat, dock and steps leading up to a cabin on gull lake

Development on or near bluffs and steep slopes often results in erosion, slope failure, landslides, and visual impacts to these sensitive natural features. 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. The interaction of these factors affects bluff and slope stability. 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:

Community Resources

Strategies for Reducing Risk of Slope Failure

Strategies for reducing the risk of slope failure will vary depending on local risk factors. General approaches include:

  • Surface grading on or near slopes to minimize slope erosion and saturation of slopes
  • Establishing and maintaining vegetation that helps stabilize slopes
  • Using erosion-control and stormwater management measures to reduce erosion and overland flow
  • Planning and zoning land for uses compatible with bluffs and steep slopes
  • Regulating placement and design of structures and land alteration in bluff and steep slope areas
  • Public education and outreach

The following materials provide basic information on the risks and mitigation approaches for local governments and property owners:

Bluff and Steep Slope Identification

It can be difficult to determine whether a slope meets the bluff definition without field verification. An onsite survey is recommended for regulatory and building purposes. For other purposes, approximate locations of a bluff can be determined using digital methods.

Digital Methods for Bluff Identification

The following methods use LiDAR-based elevation data to identify where bluffs may exist. These resources are for planning purposes.

Field Survey Methods for Bluff Identification

A field survey is necessary to locate definitive bluff boundaries for building purposes.