EVALUATION OF DETACHED BREAKWATER SYSTEM AND GROYNES FOR SUSTAINING THE COASTLINES

The effectiveness of submerged, detached breakwaters and transition groynes for the protection of Alappad coast in Kerala is numerically investigated using the software MIKE 21. The study area comprises of a coastal stretch of 3.5 km along shore and 6.5 km offshore. Results reveal predominant longshore transport which favours the s election of groynes as a coastal protection measure whereas the introduction of submerged, detached breakwaters reduced the wave height in its lee to a significant amount. Parametric studies are conducted to compare the effectiveness of detached breakwaters and groynes in reducing the coastline erosion and also to reach a suitable configuration of transition groynes that drastically reduces the sediment transport rate especially during monsoon.