EROSION MECHANISM OF NGA BAY RIVERBANKS, HO CHI MINH CITY, VIETNAM

Abstract

Nga Bay river is a main river navigation channel from East Sea to Sai Gon port. Although Nga Bay riverbanks are covered by dense mangrove trees, those have been eroded severely. Field investigation, GIS and numerical model (MIKE 21) were carried out to determine and analyze the erosion mechanism in this river mouth. The actual erosion rate was determined by erosion investigation stakes was about 10 m/y. These results corresponded with GIS analyses. The main destroyed factors were currents, waves and ship-generated waves. However, mangrove trees were the main protected factors destroyed by local population for economic activities. The numeral results showed that current speed around river mouth area is stronger than critical resistance of riverbank materials and caused severe erosion.