Nearshore sediment dynamics of Kavaratti Island, Lakshadweep archipelago using integrated modelling system

Abstract

The Kavaratti Island of Lakshadweep archipelago exhibits high coastal erosion and shoreline changes due to the anthropogenic stresses on the island morphology. This study focuses on the shoreline analysis using Digital Shoreline Analysis System model and nearshore sediment dynamics using an integrated modeling system with high resolution bathymetry of ~15 m. The sediment load and bed level change were estimated using the sediment transport model through the feedback mechanism of flow and wave forces. The model simulations were performed during winter, pre-monsoon, monsoon and post-monsoon seasons for the year 2015 and calibrated using the field observation datasets. Shoreline change studies indicate the coastal erosion of about 83.43 % and accretion of about 16.55 % along the island coast. The study signifies the erosion around the fishing jetty and accretion at the western (Katchery) jetty due to wave induced currents and tidal influx. The scouring effect due to the presence of tetrapods along the island coast is observed between 0.02 and 0.18 m.