Author(s): Rafael Almar; Jean-Pierre Lefebvre; Natalie Bonneton; Philippe Bonneton; Dinh Van Uu; Nguyen Trung Viet; Le Thanh Binh; Nguyen Viet Duc
Linked Author(s): Trung Viet Nguyen
Keywords: Wave reflection and dissipation; Low energy environments; Swash video poles; Wind-waves; Typhoon impact
Abstract: Several major typhoons hit the Vietnamese coast every year, inducing punctual dramatic erosions. The post-typhoon wave conditions, dominated by swash processes are thus crucial to reconstruct the beaches. However, only little is known on the swash processes and their contribution to wave energy dissipation and beach evolution. Two field experiments were conducted at Nha Trang; the first in May 2013 during summer monsoon (low energetic oblique wind waves) and the second in December 2013 during winter monsoon (moderate energetic shore-normal swell waves). Specific innovative instrumentation was deployed, based on a combination of cross-shore video poles, micro-ADV profiler and pressures sensors to study the swash hydrodynamic processes and associated bed evolution. This setup allowed describing the wave energy transfers, dissipation and reflection in the swash, swash-induced current, as well as to understand the individual wave/group impact on bed evolution. This study contribute in addressing the questions of integrated contribution of small-scale swash processes to the overall shoreface evolution (equilibrium concept) as well as energy balance (low frequency swash filter).