Shore protection for the coast of Mousuni Island in West Bengal, India

Abstract

The Mousuni Island in West Bengal, India is wide-open to Bay of Bengal. This island by virtue of its location is exposed to river flow as well as wave action. It is thus subjected to severe erosion along its south-western coastal stretch and also significantly affecting agriculture due to seawater inundation. This is due to the lower level of bund crest elevation combined with high water levels during coastal flooding. The most suitable method to arrest the shore erosion and salt water intrusion is to divert the flow gradually toward the deeper section of the channel. To meet this requirement, after carrying out a comprehensive profiling of the existing bund, bank connected series of spurs with locally available construction materials and unskilled labor are proposed. In order to design these spurs, the magnitude and direction of sediment movement along the stretch is estimated. The layout of protection measures is proposed based on a detailed analysis of site conditions and the environmental conditions. The tranquility inside the proposed coastal protecting structure is substantiated with a two-dimensional horizontal flow model. Furthermore, the behavior of the shorelines has been studied numerically with the proposed coastal protection measure. The detailed analysis of the results from the numerical model and the protection measure are discussed in this article.