Modeling of spur dikes effect on bank erosion control using CCHE2D

The aim of this research was to apply a two-dimensional depth-averaged hydrodynamic model capability to predict and investigate flow field, sediment transport and bank erosion in a natural meandering river. Study area is a meander of Karun River with the length of approximately 5 km between Ahvaz and Farsiat hydrometric stations. Bank protection of the so¬-called meander is so important because the Khuzestan Water and Energy company structures and agricultural farms are located in the vicinity. Mesh generation was performed by CCHE-MESH model. The validated CCHE2D model was applied for flow and sediment simulation in a 20 years period of time. Results showed the meander thalweg was decreased between 4 to 8 m and 5.7 m in average (in compare with initial bed level) and secondary flow caused a higher decrease in outer bank elevation. Spur dike structure was designed in the CCHE-2D model because of its capability to river bank protection. After 20 years of simulation, dikes caused to increase the elevation of outer bank between 1 to 9 m and 4.7 m in average (in compare with 20 years of simulation without dikes), But in some sections thalweg became approximately 4m deeper.