Poonthura, located along Kerala’s southwest coast, was experiencing persistent coastal erosion caused by chronic wave action. Continuous wave attack resulted in progressive loss of the beach, reducing the natural shoreline buffer and increasing vulnerability for the local coastal fishing community. The situation created an urgent need to address the continuing degradation of the shoreline and protect the coastal environment and the communities dependent on it.
The project focused on the affected coastal stretch at Poonthura, where repeated erosion had significantly altered the beach profile over time. The coastal setting, characterised by marine soft soil and continuous exposure to wave forces, further intensified the challenge. The loss of beach area not only affected shoreline stability but also increased the exposure of nearby settlements and fishing-related activities to coastal hazards. The project therefore addressed the need to arrest ongoing shoreline erosion and facilitate the gradual recovery and restoration of the beach along this vulnerable stretch.
KSCADC | NIOT | KIIFB
A Submerged segmental reef system using the TechTube® system is implemented to address coastal erosion at Poonthura, Kerala. The TechTube® units were installed approximately 125 m offshore at a depth of around 6 m, forming a submerged reef designed to absorb and dissipate incoming wave energy before it reached the shoreline. This helped reduce wave impact and created favourable conditions for sand trapping and beach accretion.
The original design comprised three layers of geotextile tubes, with a designed height of 2.0 m per tube in each layer. However, because of the Proficiency in underwater installation and TechTube® fabric, the implemented configuration achieved a height of approximately 2.5 m per tube in each layer using just two layers of TechTube® units. This resulted in the elimination of the third layer completely, delivering material savings, reduced construction time and cost, while maintaining the intended coastal protection objective.
The submerged reef system incorporated with TechTube® units filled with sand slurry, scour-apron geotextile and void-filling geotextile bags, creating an engineered submerged reef capable of functioning effectively below the coastline.
The Poonthura project demonstrates how an engineered submerged geotextile tube reef can combine coastal protection with shoreline recovery. By reducing offshore wave impact and creating conditions for sand retention, the intervention has supported visible beach formation since the project’s implementation in 2020. The shoreline has gradually recovered over the 6 years now, with aerial mapping indicating approximately 36,000–37,000 sqm of beach area along an 850 m stretch. The project highlights a practical approach to enhancing coastal resilience.
The project has received notable media coverage for its innovative approach to coastal erosion management and shoreline recovery. Leading publications, including The Hindu and Mathrubhumi, have featured the project, highlighting the performance of the geotextile-tube intervention, beach formation and its positive impact on the coastal community. The coverage reinforces the project’s field performance and demonstrates the growing recognition of innovative, sustainable approaches to coastal protection and resilience.
