A simple physically-based model for predicting sand transport dynamics in the Lower Mekong River

作者：Camenen B^*; Le Coz J; Dramais G; Peteuil C; Fretaud T; Falgon A; Dussouillez P; Moore S A

来源：7th International Conference on Fluvial Hydraulics (River Flow), 2014-09-03 to 2014-09-05.

The present paper provides results from a recent study for predicting total sand transport in the Lower Mekong River with twofold purposes: (1) some field experiments were carried out in September 2012 and August 2013 at Luang Prabang, nearby Xayaburi (Lao PDR), at Khong Chiam (Thailand) and at Kratie (Cambodia) to estimate sediment fluxes at relatively high discharges, and (2) a simple physically-based model is provided to estimate both bedload and suspended load for sandy particles at any discharge. Field measurements were achieved using ADCP profilers and sediment sampling. Bedload was measured using a Helley-Smith sampler and suspended load using a Delft bottle and a Niskin-type 2 L sampler. Seventeen additional field campaigns using a Delftbottle were achieved at regular intervals by a contractor nearby Xayaburi from April 2012 to March 2013, and were used for this study. The model is based on rating curves (stage-discharge relationships at the specific sections) to estimate main hydraulic parameters, such as velocity and bed shear stress. Sediment transport is then estimated using Camenen & Larson (2005, 2008) semi-empirical formulas for bedload and suspended load, respectively. A major difficulty for the model application is the possible evolution of the bottom level and sediment availability during the monsoon period. The quality of the stage-discharge relationship also significantly influences the results. Keeping in mind the uncertainties resulting from field data, the model yields quite good results compared to the experimental data. It is useful to extrapolate results to other water discharges, in order to establish long-term sediment budgets, especially when few sand transport measurements are available.

• 出版日期2014