Predicting morphodynamic processes in braided rivers — based on an experimental river

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Haiyan Yang, BINLIANG LIN

Wednesday 1 july 2015

11:30 - 11:45h at Oceania (level 0)

Themes: (T) Sediment management and morphodynamics, (ST) River morphodynamics

Parallel session: 9B. Sediment - River

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Numerical models provide considerable assistance in the investigation of the complicated processes in natural rivers. In the present study, a physics-based two-dimensional model has been employed to simulate the morphodynamic processes in braided rivers based on an experimental braided river in lab. The model applies the basic hydrodynamic and sediment transport principles with bed morphology deformation and a TVD scheme for solving trans-critical flows. A multiple bed layer technique has been applied to represent the vertical sediment sorting process. The non-equilibrium transport process of graded bed load sediment is modelled using a multiple fractional method. The model has been used to predict an experimental river with bed load. The river evolution processes and braiding mechanisms are investigated and compared with the experimental and natural rivers. Four types of avulsions have been found in the braided pattern evolution process, and they represent the primary ways in which channels change in the river. The growth and relationship of active braiding intensity and total braiding intensity show similar trends to those of the experimental river. The model demonstrated its potential to predict the morphodynamics in natural rivers.