Thiruvananthapuram: Poonthura, one of the coastal areas in Kerala worst affected by sea erosion, is witnessing a significant recovery of its shoreline following the successful implementation of an offshore breakwater project.

Over the past decade, repeated episodes of severe coastal erosion had destroyed the homes, assets, fishing boats and equipment of local fishing communities in Poonthura. Several lives were also lost, and temporary relief measures involved relocating residents to different areas. In search of a permanent solution, the state government decided to implement an offshore breakwater project using geotextile tubes, with technical support from the National Institute of Ocean Technology (NIOT), Chennai.

The project was entrusted to the Kerala State Coastal Area Development Corporation (KSCADC). As part of a pilot initiative, an offshore breakwater using geotextile tubes (geo-tubes) was installed in the deep sea off the Poonthura coast. The trial has delivered promising results, with nearly half of the eroded coastline successfully reclaimed — a major achievement for the project.

What are geo-tubes?

Geo-tubes, or geotextile tubes, made from high-strength polyester or polypropylene, are used to reduce the force of strong sea waves.

The tubes will be installed in lengths of 20, 16 and 12 metres, with a diameter of 1.5 metres. Each breakwater will extend for 100 metres, with successive structures placed 50 metres apart. The tubes will be positioned two metres below sea level and secured to hooks on concrete blocks laid on the seabed.

By the time waves pass over the geo-tubes, their intensity is expected to reduce significantly before reaching the shore, helping to naturally curb coastal erosion.

Project to be extended up to Veli

The project will be completed using ₹150 crore from Kerala Infrastructure Investment Fund Board (KIIFB) funding. While the pilot project in Poonthura was initially estimated to cost ₹22 crore, officials from the KSCADC said it was completed for just ₹16 crore, contributing to its success.

A detailed model study has now been completed for reclaiming a nine-kilometre stretch of coastline from Poonthura to Veli, covering areas such as Beemapally, Cheriyathura, Valiyathura, Valiyathoppu, Shangumugham and Vettucaud. The project will be extended to these areas once government approval is granted.

Seawall no longer required, say fisherfolk

“There is no longer any need for stone embankments. With the installation of geo-tubes, we have gained more shoreline. There is now space to park fishing boats, and the impact of large waves hitting the shore has reduced significantly,” said Don Bosco, a fisherman from Poonthura.

“The suffering we endured for years has reduced considerably. The destruction of our homes during high tide has been controlled. The lost coastline has returned. The geo-tube project has been a lifeline for our families,” said fisherman Sousa Marian.