HAL will be down for maintenance from Friday, June 10 at 4pm through Monday, June 13 at 9am. More information
Skip to Main content Skip to Navigation
Journal articles

Morphodynamics of the exit of a cutoff meander: experimental findings from field and laboratory studies

Abstract : The morphological evolution of the entrances and exits of abandoned river channels governs their hydrological connectivity. The study focusses on flow and sediment dynamics in the exit of a cut-off meander where the downstream entrance is still connected to the main channel, but the upstream entrance is closed. Two similar field and laboratory cases were investigated using innovative velocimetry techniques (acoustic Doppler profiling, image analysis). Laboratory experiments were conducted with a mobile-bed physical model of the Morava river (Slovakia). Field measurements were performed in the exit of the Port-Galland cut-off meander, Ain river (France). Both cases yielded consistent and complementary results from which a generic scheme for flow patterns and morphological evolution was derived. A simple analogy with flows in rectangular side cavities was used to explain the recirculating flow patterns which developed in the exit. A decelerating inflow deposits bedload in the downstream part of the cavity, while the upstream part is eroded by an accelerating outflow, leading to the retreat of the upstream bank. In the field, strong secondary currents were observed, especially in the inflow, which may enhance the scouring of the downstream corner of the cavity. Also, fine sediment deposits constituted a silt layer in a transitional zone, located between the mouth of the abandoned channel and the oxbow-lake within the cut-off meander. Attempts at morphological prediction should consider not only the flow and sediment conditions in the cavity, but also the dynamics of the main channel.
Document type :
Journal articles
Complete list of metadata

Cited literature [27 references]  Display  Hide  Download

https://hal.archives-ouvertes.fr/hal-01058300
Contributor : Import Ws Irstea Connect in order to contact the contributor
Submitted on : Tuesday, August 26, 2014 - 3:11:31 PM
Last modification on : Wednesday, March 23, 2022 - 9:04:01 AM
Long-term archiving on: : Thursday, November 27, 2014 - 4:13:02 PM

File

LY2010-PUB00027396.pdf
Files produced by the author(s)

Identifiers

  • HAL Id : hal-01058300, version 1
  • IRSTEA : PUB00027396

Citation

J. Le Coz, M. Michalkova, A. Hauet, M. Comaj, Guillaume Dramais, et al.. Morphodynamics of the exit of a cutoff meander: experimental findings from field and laboratory studies. Earth Surface Processes and Landforms, Wiley, 2010, 35 (3), pp.249-261. ⟨hal-01058300⟩

Share

Metrics

Record views

290

Files downloads

281