Journal of Geophysical Research: Earth Surface

Cover image for Vol. 122 Issue 12

Impact Factor: 3.412

ISI Journal Citation Reports © Ranking: 2016: 33/188 (Geosciences Multidisciplinary)

Online ISSN: 2169-9011

Associated Title(s): Journal of Geophysical Research

Sediment capacitors help explain debris flow events

Runoff during rainstorms plays a key role in initiating many debris flow events, but exactly how these debris flow events begin is not well understood. To better understand how debris flows are initiated by runoff, Kean et al. monitored both the triggering rainfall and the associated debris flow at two small catchments: a bedrock-dominated alpine basin in central Colorado and a recently burned area in southern California. They also studied video footage from cameras at the Colorado site.

They found that both sites had debris flow surge characteristics that varied with rainfall intensity and that the flow patterns were influenced by variations in the channel slope. In particular, the authors suggest that low-slope areas in a channel can temporarily store debris, acting as “sediment capacitors.” These low-slope areas then periodically release the accumulated debris in a debris flow surge. Most importantly, their “sediment capacitor” model explains both the debris flow initiation process and observed variations in debris surge magnitude and frequency.

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