An analysis of coastal erosion in the tropical rapid accretion delta of the Red River, Vietnam
Abstract: The largest plain in the North Vietnam has formed by the redundant sediment of the Red River system.
Sediment supply is not equally distributed, causing erosion in some places. The paper analyzes the
evolvement and physical mechanism of the erosion. The overlay of five recent topographical maps
(1930, 1965, 1985, 1995, and 2001) shows that sediment redundantly deposits at some big river mouths
(Ba Lat, Lach, and Day), leading to rapid accretion (up to 100 m/y). Typical mechanism of delta propagation
is forming and connecting sand bars in front of the mouths. Erosion coasts are distributed either
between the river mouths (Hai Hau) or nearby them (Giao Long, Giao Phong, and Nghia Phuc). The
evolvement of erosion is caused by wave-induced longshore southwestward sediment transport. Meanwhile
sediment from the river mouths is not directed to deposit nearshore. The development of sand bars
can intensively reduce the erosion rate nearby river mouths. Erosion in Hai Hau is accelerated by sea level
rise and upstream dams. Sea dike stability is seriously threatened by erosion-induced lowering of beach
profiles, sea level rise, typhoon, and storm surge.
Project metadata: http://www.apn-gcr.org/resources/items/show/1703