A Field Experiment for Coastal Dune Reconstruction

Coastal dunes, as a whole, represent a natural barrier between the sea and the land, playing a vital role in the coastal defense against the waves and tides. Compared to the use of hard, man-made structures, not only is it a less expensive method to counteract the coastal erosion problems, but it is also a method that has higher ecological and scenic values in the environmental management aspect. In this research project, a field experiment was conducted for dune reconstruction at the Ching-tsao-lun reach of the Tainan coast where the foredunes had been eroded and washovered by a previous typhoon. Three experimental sets were put up to re-build foredunes that have been previously damaged, and a small natural remnant dune was chosen as the comparison set for evaluating the effectiveness of the reconstruction of foredunes. The dune building processes were observed by monitoring the changes of dune profiles, surface sand grain size, and the vegetation density. The experiment results are used to create an appropriate dune rehabilitation suggestion for this area. The results reveal that a bulldozed artificial dune can raise the dune height immediately, and putting racks on the bare sand surface can help the accumulation of sand and the colonization of vegetation that will quickly stabilize the artificial foredune. Keyword : dune reconstruction; vegetation rehabilitation; sand fence accumulation; artificial dune