Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 15, 1955-1962, 2015
https://doi.org/10.5194/nhess-15-1955-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
02 Sep 2015
Selective deposition response to aeolian–fluvial sediment supply in the desert braided channel of the upper Yellow River, China
H. Wang1,a, X. Jia1, Y. Li1, and W. Peng1 1Key Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Institute, Chinese Academy of Sciences, Gansu Province 730000, China
anow at: Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, 260 Donggang West Road, Lanzhou, Gansu Province, 730000, China
Abstract. Rivers flow across aeolian dunes and develop braided stream channels. Both aeolian and fluvial sediment supplies regulate sediment transport and deposition in such cross-dune braided rivers. Here we show a significant selective deposition in response to both aeolian and fluvial sediment supplies in the Ulan Buh desert braided channel. The Ulan Buh desert is the main coarse sediment source for this desert braided channel, and the mean percentage of the coarser (> 0.08 mm) grains on the aeolian dunes surface is 95.34 %. The lateral selective deposition process is developed by the interaction between the flows and the aeolian–fluvial sediment supplies, causing the coarser sediments (> 0.08 mm) from aeolian sand supply and bank erosion to accumulate in the channel centre and the finer fluvial sediments (< 0.08 mm) to be deposited on the bar and floodplain surfaces, forming a coarser-grained thalweg bed bounded by finer-grained floodplain surfaces. This lateral selective deposition reduces the downstream sediment transport and is a primary reason for the formation of an "above-ground" river in the braided reach of the upper Yellow River in response to aeolian and fluvial sediment supplies.

Citation: Wang, H., Jia, X., Li, Y., and Peng, W.: Selective deposition response to aeolian–fluvial sediment supply in the desert braided channel of the upper Yellow River, China, Nat. Hazards Earth Syst. Sci., 15, 1955-1962, https://doi.org/10.5194/nhess-15-1955-2015, 2015.
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Short summary
Rivers flow through aeolian dunes and always adopt braided stream channels in response to aeolian and fluvial sediment supplies. Here our results indicate that these braided rivers are distinguished from coarser-grained thalweg beds and finer-grained bar or floodplain surfaces and develop a significant lateral selective deposition in bed sediment. The traditional downstream fining shows no significance in this braided channel, primarily due to aeolian sand supplies.
Rivers flow through aeolian dunes and always adopt braided stream channels in response to...
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