Premium
What controls channel form in steep mountain streams?
Author(s) -
Palucis M. C.,
Lamb M. P.
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl074198
Subject(s) - streams , cascade , channel (broadcasting) , geology , debris flow , sediment transport , debris , sediment , stream bed , geomorphology , flow (mathematics) , bedform , bed load , stream power , hydrology (agriculture) , geotechnical engineering , mechanics , physics , chemistry , computer network , oceanography , chromatography , computer science , electrical engineering , engineering
Steep mountain streams have channel morphologies that transition from alternate bar to step‐pool to cascade with increasing bed slope, which affect stream habitat, flow resistance, and sediment transport. Experimental and theoretical studies suggest that alternate bars form under large channel width‐to‐depth ratios, step‐pools form in near supercritical flow or when channel width is narrow compared to bed grain size, and cascade morphology is related to debris flows. However, the connection between these process variables and bed slope—the apparent dominant variable for natural stream types—is unclear. Combining field data and theory, we find that certain bed slopes have unique channel morphologies because the process variables covary systematically with bed slope. Multiple stable states are predicted for other ranges in bed slope, suggesting that a competition of underlying processes leads to the emergence of the most stable channel form.