Road Related Landslides
Landslides with the potential to fail during periods of intense and prolonged rainfall events are identified in the field by tension cracks, scarps showing vertical displacement, corrective regrowth on trees, and perched, hummocky fill indicating surface instability. Types of road related landslides typically include (1) road fill failures, (2) landing fill failures, (3) hillslope debris slides, and (4) deep-seated, slow landslides. The majority are often the result of failure of unstable fill and sidecast material from earlier road construction. Preemptive excavation of small, current or potential landslides is an effective technique for erosion control, achieved by removing the unstable material and redepositing it in a stable, designated location either at or near the treatment site.
Examples of Road-Related Landslides
Road fill failure on stream-side road. (PWA)
Fill slope failures on roads built on steep slopes near stream channels have a high likelihood of delivering sediment directly to the stream channel. (PWA)
Examples of Unstable Fillslope Excavation
Example 1 Before and After:
Example 2 Before and After:
What should I do about road related landslides?
- Contact the Marin RCD: call, email, or use the submission form in the sidebar of this page.
- Secure permits: This practice may sometimes require permits.