Debris Basin

What – Specially engineered and constructed emergency basin for storing large amounts of sediment moving in an ephemeral stream channel.  Designed to trap at least ~ 50–70 percent of expected flows.

Purpose – Designed to store runoff and sediment; often the last recourse to prevent downstream flooding, sedimentation, or threats to human life and property.  Provide immediate protection from floodwater, floatable debris, sediment, boulders, and mudflows.

Effectiveness – No quantitative information is available on effectiveness.  Debris basins are considered to be a last resort because they are expensive to construct and require commitment to long-term repeated maintenance following runoff events.

Where

• Areas with moderate- to high-burn severity.
• Areas where high-value resources are imminently threatened.
• Sites with the capacity to trap the estimated debris flow volume.
• Sites with access available for construction and maintenance.

Cost – Expensive; costs depend on the following factors:

• Location and access
• Size of debris basin
• Availability of material
• Frequency of maintenance

How to Links – See USDA BAER Catalog page 102 (PDF page 110); NRCS Sediment Basin Fact Sheet; and Debris Dam Publication.