Numerical modelling approach for the feasibility of shore protection measures along the coast of Kavaratti Island, Lakshadweep archipelago

Erosion along Kavaratti Island has intensified in recent times due to infrastructure development and natural phenomenon. Numerical models were used to identify suitable foreshore protection structures, considering the near-shore coastal processes. For this purpose, shoreline change around the island was obtained from field surveys and results of the DSAS model. Subsequently, model simulations were conducted for the most appropriate use of structural protection measure to understand the change in hydrodynamics and sediment transport, which would ultimately result in stabilization of the Kavaratti Island coast. Based on the prevailing conditions, suitable site-specific coastal protection structures (e.g., groynes, revetment, breakwater, submerged geo-tubes structures and submerged breakwater) were assessed to determine the most feasible and suitable shore protection measure and observed the following: (a) Revetment and submerged geo-tube structure to be the most effective protection measures on the eastern part of the Kavaratti Island, (b) significant decrease in current speed from 0.48 to 0.05 m/s, and (c) significant decrease in wave height (from 2.5 to 0.3 m) and wave energy reduction about 50% from the prevailing conditions were observed. With this intervention, the existing shoreline of the island would at least be maintained, possibly preventing any further loss of land.