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Dynamic controls on erosion and deposition on debris-flow fans

Schürch, P.; Densmore, A.L.; Rosser, N.J.; McArdell, B.W.

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P. Schürch

B.W. McArdell


Debris flows are among the most hazardous and unpredictable of surface processes in mountainous areas. This is partly because debris-flow erosion and deposition are poorly understood, resulting in major uncertainties in flow behavior, channel stability, and sequential effects of multiple flows. Here we apply terrestrial laser scanning and flow hydrograph analysis to quantify erosion and deposition in a series of debris flows at Illgraben, Switzerland. We identify flow depth as an important control on the pattern and magnitude of erosion, whereas deposition is governed more by the geometry of flow margins. The relationship between flow depth and erosion is visible both at the reach scale and at the scale of the entire fan. Maximum flow depth is a function of debris-flow front discharge and pre-flow channel cross-section geometry, and this dual control gives rise to complex interactions with implications for long-term channel stability, the use of fan stratigraphy for reconstruction of past debris-flow regimes, and the predictability of debris-flow hazards.


Schürch, P., Densmore, A., Rosser, N., & McArdell, B. (2011). Dynamic controls on erosion and deposition on debris-flow fans. Geology, 39(9), 827-830.

Journal Article Type Article
Publication Date Aug 1, 2011
Deposit Date Oct 20, 2011
Publicly Available Date Oct 16, 2013
Journal Geology
Print ISSN 0091-7613
Electronic ISSN 1943-2682
Publisher Geological Society of America
Peer Reviewed Peer Reviewed
Volume 39
Issue 9
Pages 827-830


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