Application of two-dimensional hydrodynamic model (MIKE 21FM) to simulate the sediment regime on Hau river, piloted in Long Xuyen city - An Giang province

Abstract

The problem of studying, calculating, simulating the process of transporting sediment and calculating erosion and accretion in rivers is very complicated. There are many methods that are applied and have shown their own effectiveness. However, at present, the development of a computer system as well as a good data base (especially topographic data) will ensure the ability to apply hydrodynamic models to simulate high results. In the Mekong Delta, there are currently 406 landslide sections, with a total length of 891km, of which An Giang is assessed as one of the localities most severely affected by riverbank erosion. Currently, there are many methods used to assess and predict riverbank erosion through the calculation of sediment content and regime in the river in specific areas, such as: document analysis method. real measurement; physical model; experience formula and mathematical model. Research using 2D Mike 21FM model is being widely used to simulate sediment regime on Tien and Hau river systems and analyze in detail for Long Xuyen city, An Giang province, which is a serious landslide area in recent years. The criteria to evaluate the reliability of the model both in terms of hydrodynamics and sediment at Vam Nao hydrological station show that the set of parameters ensures enough reliability to conduct the simulation of sediment on the system. Simulation results of flow regime and velocity show that the direction of sediment movement is from the right bank to the left bank, and this area has many scour holes and the level of sediment moving away from the shore is up to 50kg/m3. Many locations also clearly show a high risk of landslides in this area. This result will strengthen the scientific basis of the mathematical modeling method along with other methods for simulating finding mechanisms and causes of riverbank erosion, serving the prevention and mitigation of riverbank erosion. damage caused by landslides.