ĐÁNH GIÁ TÍNH HIỆU QUẢ CỦA RHIZOPHORA APICULATA VÀ NYPA FRUTICANS TRONG GIẢM SÓNG DO TÀU THUYỀN GÂY RA

Abstract

Boat-generated waves have a potential to erode a riverbank, especially where there is regular boat traffic whereas vegetation might be able to protect the riverbank from that threat. A field observation conducted in Ca Mau Province, Vietnamese Mekong Delta, investigated the interaction between boat-generated waves and vegetation. Two types of vegetation, Rhizophora apiculata, a mangrove species that has dense aerial roots, and Nypa fruticans, a palm species, were considered with respect to wave attenuation. The results indicated that both R. apiculata and N. fruticans play essential roles in dissipating wave energy and therefore have a high potential for riverbank protection. Remarkably, more than 50% of the wave height reduction can be obtained in a relatively short distance inside the vegetation belt. The vegetation porosity strongly affects the wave attenuation. In addition, R. apiculata was more effective than N. fruticans in wave height reduction, even though their porosity is greater. The special aerial root configuration of R. apiculata induces greater drag force that might account for this phenomenon.