Morphology Evolution of Cuadai Estuary, Mekong River, Southern Vietnam

Abstract

Morphology evolution of estuarine systems is a complex phenomenon. The primary processes (involving waves, currents, sediment transport, and their interaction with topography changes) are not fully understood at different spatial and temporal scales, under either natural situations or intensified human interventions. The Mekong River Delta, one of the most socioeconomically important deltas in Vietnam, is experiencing a dramatic morphological change with natural and human interventions. For example, the Cuadai estuary, one of the biggest of the Mekong River’s estuaries, is undergoing an intricate change of river shore. The highly dynamic variation of the estuary significantly influences the local economy. Basically, there are four classified methods in research of morphology evolution, including (1) theoretical analysis, (2) field investigation, (3) physical modeling, and (4) numerical modeling. Each method has its advantages and disadvantages. Previous studies analyzed survey data or employed remote-sensing techniques. However, no sufficient and scrupulous investigation has been conducted for the effects of different factors. In this paper, an attempt is made to determine the key factors by setting up a numerical model to simulate the morphological change of this estuary with a coupled model flexible mesh. After calibration with the measured data in 2002 and 2003, it is applied to analyze the erosion/deposition pattern of this estuary. The key factors are identified and the influences of the key factors on the morphological evolution are analyzed.