Physical Model of Natural Coastal Protection System: Geobag-Dyke Performance to Effectiveness of Natural Coastal Protection System

Abstract

One of the potential hazards that can cause major problems in coastal areas is erosion. In order to solve this problem, the notion of sustainable coastal development has garnered growing attention around the world. Coastal zone management mechanisms aim to ensure the sustainability of resources and the environment. For example, natural coastal protection using vegetation such as mangrove trees is currently preferred in many places in the world. However, there are challenges in the development of this natural form of coastal protection, e.g. mangrove seedling trees can be damaged by the waves or the current before they grow strong enough, and thus require appropriate protection until at least two years after planting. To solve this problem, a natural coastal protection system that combines a main natural protection and a temporary man-made structure is proposed. After a process of weighing temporary man-made-structure alternatives, the geobag dyke was selected. This study aimed to quantify the effects of various geobag dyke configurations and geobag unit weights on wave height reduction. Laboratory experiments were conducted on a narrow wave flume using a mangrove model as main natural protection and geotextilegeobag models as temporary man-made structures. Various wave conditions were generated during the laboratory tests. This paper focuses on the experimental results of wave transmission through the protection system in order to determine the most effective geobag dyke configuration to reduce the wave height. Based on experimental modelling, the most effective geobag dyke configuration uses relatively heavy geobag units with a moderate dyke slope (1:1.5).

Comparative of material properties between natural fibers and geo-bag synthetic fibers as sustainable material of temporary structure in natural coastal protection systems

“…Therefore, to mitigate coastal erosion problems, coastal regions worldwide are focusing on sustainable coastal development practices by planting natural vegetation, such as mangroves. However, the planting of young mangrove seedlings is frequently damaged by sea currents or waves before the mangroves can grow strong enough to protect coastlines [2]. At least three years are required to ensure that mangroves can grow strongly [3].…”