Applying a two dimensional open source hydro dynamic model to evaluate the riverbed change in the upstream of the Cuu Long River, An Giang province

Abstract

River bank erosion in the Mekong Delta, particularly along the Tien and Hau rivers and some primary and secondary tributaries, is undergoing highly complex and unpredictable changes, resulting insignificant damage to the affected areas. The phenomenon of river bank erosion here is caused by multiple factors, including intensified human activities such as sand mining, infrastructure development, and climate change. In recent years, the increasing activities of upstream Mekong River projects have led to a reduction in sediment deposition in the delta, which is considered one of the significant contributing factors to the increasing incidence of river bank erosion. This paper will apply and build a two-dimensional open source model (TELEMACO) to simulate in detail the sediment transport process during the 3-year period from 2017 to 2019 on the upstream section of the Tien and Hau rivers in An Giang province to evaluate and assess the sediment imbalance during this period and identify trends in riverbed erosion and deposition. As a result, in 3 years, the total silt deficit on the Tien River section is -36.6×106 m³, on the Hau River is -2.7×106 m³. At the same time, the erosion depth deepened by approximately 0.25-0.75 m (especially up to 1.0 m). This indicates an imbalance in sediment deposition and erosion, with a consistent trend of riverbed, banks, and shore erosion.