Debris-flow Information
Contact Information
PI-70 (pdf)

Public Information Series 70
by William F. Case

Debris-flow risk can be reduced by:

1. preventing debris from entering a stream channel,
2. trapping debris on a hillside, in the channel or in a debris basin before it reaches developed property; or
3. distributing or diverting debris on the alluvial fan away from structures.

Sediment fence reduces erosion
on a wet slope denuded by a wild
fire, Freeze Creek, Salt Lake County.

Most of the debris in a debris flow is picked up as the flow moves down a stream channel; the debris collects in the channel from slope erosion or from other debris flows that did not make it to the mouth of the canyon.

Slope erosion can be reduced by terracing, reseeding after wild fires, and intelligent land use such as controlled grazing.

Debris can be trapped using sediment fences on slopes, gabion baskets or check dams in channels, and debris basins on alluvial fans.

With proper design and construction, debris and water can be diverted away from buildings by a "plow-shaped" deflection wall, or debris can be trapped with a chain-link fence strengthened to hold the debris.

Gabion used to trap debris in Freeze Creek, Salt Lake County.	Debris basin in Farmington, Davis County, to trap debris flows issuing from Rudd Creek.