Erosion Control Toolbox: Stepped Slopes
Introduction
This technique consists of a series of small benches, typically between one and two feet in width. Stepped slopes control erosion by breaking up the slope length, which reduces the velocity of stormwater runoff. The steps promote vegetative cover by capturing and retaining loose soil material.
Stepped Slopes Training Video
Click here to watch a short video about Stepped Slopes.
When to Use This Treatment
- Use on excavation (cut) slopes between 2:1 and 1.5:1 (H:V)
- For slopes steeper than 2:1 (H:V) a Geotechnical Design Report should be prepared by Caltrans Division of Engineering Services (DES) Office of Geotechnical Services
Consider Using With
Benefits
- Reduced stormwater runoff volume and velocity
- Improved soil, seed, and water holding capacity on steep slope surfaces
- Improved potential for establishing vegetative cover on steep cut slopes
Limitations
- May increase the cost of earthwork activities
- Requires site accessibility by earthwork equipment
- May not be practical for sandy or rocky soils
- For cut slopes only
Standard Specifications
- Refer to Standard Specifications - Section 19 Earthwork
Plans and Details
- Indicate stepped slope tread and riser dimensions in a detail on the project plans
Guidance
- Highway Design Manual (HDM) Chapter 300, Topic 304.5 Stepped Slope
- Highway Design Manual Topic 110.2(2)(b) recommends slope roughening techniques such as stepped slopes, trackwalking, scarification, and sheeps foot rolling to minimize erosion and promote plant growth
- Caltrans Storm Water Quality Handbooks Project Planning and Design Guide (PDF) , Appendix A, Slope Roughening/ Terracing/ Rounding/ Stepping
- California Department of Transportation, "Performance of Erosion Control Treatments on Reapplied Topsoil" (PDF) , May 2005
- Caltrans Erosion Control Webinars
References
- David Steinfield, Scott Riley, Kim Wilkinson, Thomas D. Landis, Lee Riley, et. al. 2017. "Roadside Revegetation: An Integrated Approach to Establishing Native Plants and Pollinator Habitat"
- Chapter 3.1.1 Developing a Vegetation Management Strategy during Project Design
- Chapter 5.3 - 5.4 Obtaining Plant Materials, Installing Plant Materials Chapter
Updated: December 17, 2018