thumbnail

Distinguishing between debris flows and floods from field evidence in small watersheds

Fact Sheet 2004-3142

By:

Links

Abstract

Post-flood indirect measurement techniques to back-calculate flood magnitude are not valid for debris flows, which commonly occur in small steep watersheds during intense rainstorms. This is because debris flows can move much faster than floods in steep channel reaches and much slower than floods in low-gradient reaches. In addition, debris-flow deposition may drastically alter channel geometry in reaches where slope-area surveys are applied. Because high-discharge flows are seldom witnessed and automated samplers are commonly plugged or destroyed, determination of flow type often must be made on the basis of field evidence preserved at the site.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Distinguishing between debris flows and floods from field evidence in small watersheds
Series title:
Fact Sheet
Series number:
2004-3142
Year Published:
2005
Language:
English
Publisher:
U.S. Geological Survey
Contributing office(s):
Volcano Science Center, Cascades Volcano Observatory
Description:
4 p.
Number of Pages:
4