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L. Lyu, M. Xu, Z. Wang, Y. Cui, K. Blanckaert:
"A field investigation on debris flows in the incised Tongde sedimentary basin on the northeastern edge of the Tibetan Plateau";
CATENA, 208 (2022), 105727.

An investigation on 152 gullies along the Daheba River in the Tongde sedimentary basin was performed. Debris
flows develop in gullies with an excess topography ZE, which represents the sediment availability, above a critical
threshold value. Debris flows in the Daheba watershed are supply-unlimited, i.e sediment is abundantly available
from the steep erodible gully banks. Debris flows consist of a head and a body. The body propagates faster than
the head and constantly supplies it with sediment. The body and head propagate in an intermittent way through
the transient storage of sediment on the riverbed and its subsequent remobilization. Although the main sediment
supply is provided by bank collapse, debris-flow events also incise the gully bed. The growth and incision of
debris-flow gullies in supply-unlimited watersheds is mainly controlled by the frequency of occurrence of debris
flows, which is closely related to ZE. With growth of the gully drainage area, ZE and the debris-flow frequency
initially increase, until they reach maximum values in gullies with a drainage area of intermediate size, which are
assumed to be the morphologically most active gullies. With further growth of the gully drainage area, ZE and the
debris-flow frequency decrease, which opposes the development of debris flows and leads to a more stable gully
morphology.

Debris flow, landscape evolution, sedimentary basin, field investigation, sediment availability

http://dx.doi.org/10.1016/j.catena.2021.105727