Assessment of challenges to Radhapuram due to temporal coastal infrastructures using hybrid approach

Developments along the coastal zone are mostly associated with coastal infrastructures. Establishment of coastal structures induce dual effects a) rendering coastal protection to its host coast b) imparts coastal instability to the adjacent coasts. This characteristic is common for most of the engineered hard structures. Radhapuram taluk is one such coastal stretch located in Tirunelveli district of Tamil Nadu. There are about 11 coastal hamlets in the taluk within 100 m to 200 m from the shore of which most of them are fishing hamlets. There are about 28 coastal structures predominantly developed between 2000 and 2020 to protect the coast.As stated, these structures provide expected coastal zone protection for their associated coast but imparts imbalance in the adjacent areas. The present study was attempted to assess the necessity and impacts of the coastal structures along the coast between 2000 and 2020 using hybrid approach. The hybrid approach involves application of Remote sensing, Geographic Information System (GIS), Digital Shoreline Analysis System (DSAS) and numerical model. The study indicated extents of erosion:accretion:stable coast in percentage ‘before’ and ‘after’ the development of coastal structures as 64:23:13 and 49:31:20 respectively. However the study also indicated the challenges to certain hamlets a) not protected with structures and b) continuing controlled erosion of certain hamlets with structures. It is noted from the study that existing and new coastal structures along the coast may not provide a permanent solution for the coastal stability of the Radhapuram taluk unless the appropriate locations close to the hamlets are further strengthened by coastal green shields to combat erosion.