HOI-AN PROJECT: STUDY OF EROSION PROCESSES AND PROTECTION MEASURES FOR HOI-AN BEACHES

Hoi An, located in central Viet Nam, around 25 kilometres south of Danang (Figure 1), is one of the most beautiful cities of Vietnam. The old town of Hoi An is listed as a UNESCO World Heritage site. Since October 2004, this well-known tourist site is under threat by severe erosion.

Cua Dai Beach, north of the Thu Bon river mouth, has retreated by almost 200m and the river channel itself has shifted south by 250m. Several construction sites at tourist resorts were swallowed by waves, bringing work to a complete standstill.

The erosion process becomes increasingly threatening, possibly for the old town itself.  Current solutions for coastal erosion are temporary and would not achieve sustainable outcomes, and might in fact do the opposite. Generally, studies remain qualitative, based on aerial and satellite images of the site.

Quantitative assessments using in-situ observations and numerical models are lacking, although they are needed in order to firmly endorse any of the proposed assumptions. This is what the present project is proposing.

The project will be to provide the large scale forcing environment of the study site (waves, tides, winds), using global solutions and produce local coupled wave-current-sediment 3D model solutions (using ROMS/CROCO) and to provide very high-resolution 2D model solutions of circulation and sediment transport for the nearshore zone and estuary (using TELEMAC2D).

These models will be used to expose the alongshore and cross-shore processes at work and test changes in sediment balance associated with changes in upstream sediment sources and various coastal protection measures. Institutes: CARE, HCMUT, WRU, VIASM, LEGOS