Thengaipattinam Harbour: Waves, Walls and the Stories they tell

Article released on January 20, 2025

Disclaimer: The views expressed in this article are my own and do not represent those of any affiliated organizations or government bodies.

Along the southwestern coast of Tamil Nadu near the southernmost point of India lies Thengaipattinam Habour, a vital lifeline
for the local fishing community. Situated where the Arabian Sea meets the Thamirabarani River, this harbour occupies a unique and precarious location. On one side, the relentless waves of the Arabian Sea batter its shores with high energy. On the other, the river's rising water levels creep closer to the homes of those who depend on the harbour for their livelihood.

The harbour is not just a place for docking boats; it's the heart of a community. Fishing is the primary livelihood of thousands of families in this region, making the harbour indispensable (Source: Times of India). However, this critical infrastructure is constantly under threat. The force of nature - high-energy waves, monsoon-driven floods, and shifting river dynamics - have created a battle for survival that the residents of Thengaipattinam fight daily.

Adding to the complexity is the geography surrounding the harbour. Just north of it lies a narrow strip of land sandwiched between the sea and the river. This strip is home to approximately 400 buildings, including homes and small businesses. Here, the stakes are even higher. Every monsoon season brings the fear of overtopping waves from the sea and erosion from the riverbank, leaving residents struggling to adapt.

For Thengaipattinam, the stakes couldn't be clearer: the harbour is more than just a physical structure. It is the lifeblood of a community that relies on it not only for economic sustenance but also for safety and stability. But as the forces of nature grow stronger, one question looms large: how long can the harbour, and the people who depend on it, hold their ground?

The construction of Thengaipattinam Harbour's breakwater has been a story of ambition, setbacks, and adaptation. Built to shield the harbour from the high-energy waves of the Arabian Sea, the breakwater has faced repeated failures due to the region's extreme coastal conditions. Below, I explore its journey from design to damage and eventual reconstruction.

The breakwater was envisioned as a critical barrier against the Arabian Sea's powerful waves, ensuring calm waters for fishing vessels to dock safely. Designed to cater to the needs of the thriving fishing community, the harbour was expected to improve safety, reduce accidents, and enhance economic opportunities for the local population.

Constructed in 2019 at a cost of Rs 97.4 crore, the breakwater was designed to create a safe docking space for fishing vessels. However, its location, characterized by high wave energy due to wave refraction and strong winds, presented significant challenges. Studies reveal the region experiences annual mean wave power between 15 and 20 kW/m, among the highest along the Indian coastline (Sanil Kumar et al 2015). This intense wave energy accelerated the degradation of the breakwater and exposed its vulnerabilities. 

Recognizing these challenges, the Tamil Nadu government sanctioned Rs 77 crore in January 2021 to extend the breakwaters by 200 meters to mitigate the wave impacts. The design was revised to account for high wave energy, incorporating materials like stones weighing 2 to 12 tonnes to enhance durability (Source: Times of India).

By August 2022, plans were announced for an additional 630-meter breakwater to protect fishermen from Thengaipattinam and nearby Erayumanthurai. Personal field experiences and satellite imagery showed gradual progress during this period, yet delays were evident. Reports suggested logistical challenges, including sourcing materials and adapting designs to the unforgiving marine environment (Source: DT Next).

Despite these efforts, community members voiced concerns about the design's alignment and effectiveness. Fishermen advocated for a 450-meter primary breakwater at a 45-degree angle to counteract the violent tides, along with entry and exit points aligned in the south-north direction (Source: The Hindu).

Satellite imagery from December 2024 suggests that significant progress has been made, with the extended breakwater appearing near completion. However, without official confirmation, the precise status remains uncertain. My comparison of images from 2023 and 2024 highlights visible improvements, particularly in areas that were previously breached.

Thengaipattinam Harbour's breakwater underscores the complexities of constructing resilient infrastructure in high-energy coastal environments. My fieldwork, combined with satellite imagery, reveals lessons that extend beyond this single harbour:

1. Local Context Matters: Engineering designs must account for site-specific conditions, such as wave energy and sediment dynamics.

2. Ongoing Adaptation is Essential: Initial construction is only the beginning - regular maintenance and redesigns are vital for long-term functionality.

3. Community voices are Crucial: Engaging fishermen and incorporating their practical knowledge can lead to more effective solutions.

Just north of Thengaipattinam Harbour lies a narrow strip of land caught between two powerful forces of nature. On one side, the Arabian Sea unleashes relentless waves, eroding its coastline. On the other, the Thamirabarani River steadily rises, creeping closer to the homes and businesses of the roughly 400 buildings perched precariously on this sandwiched land. Google's 2.5D building data highlights the density of life in this fragile zone, where residents have little room to manoeuvre as the forces of nature close in from both sides.

This unique geography makes the strip particularly vulnerable during the monsoon season. Waves frequently overtop the seawalls along the coast while the river swells and destabilizes the rear, cracking walls and weakening foundations. For those living here, the narrow margin between the sea and river is more than just physical - it is a daily battle for stability and survival.

During my 2023 fieldwork, the fragility of this strip became painfully evident. Sea-side challenges were starkly visible: roads running along the coast bore the brunt of wave action, with large sections damaged. Towering seawalls, built to protect the strip, were frequently overtopped during storms, leaving the roads unusable and exposing nearby buildings to further risks. 

On the river-side, the challenges were no less severe. Rising water levels in the Thamirabarani River had begun to destabilize the foundations of homes, leading to cracks in walls and visible signs of structural weakening. Field photos showed homes perilously close to collapse, with water encroaching dangerously near the edges of the settlement. 

Despite the looming threats, the residents of this sandwiched land continue to endure, navigating an uncertain and often dangerous existence. Damaged roads disrupt access to essential services, while homes remain at constant risk of further erosion or flooding. For many, relocation is not a viable option due to socio-economic constraints, leaving them with no choice but to adapt to these increasingly dire conditions.

The daily lives of the residents reflect their precarious situation - repairing cracked walls, clearing debris after storms, and grappling with the uncertainty of when the next disaster might strike. The narrow strip north of the harbour exemplifies the immense human cost of living at nature's mercy, underscoring the urgent need for holistic resilience efforts that go beyond protecting the harbour itself.

Thengaipattinam Harbour and its surrounding community stand as a testament to both the immense power of nature and the resilience of those who live at its mercy. The harbour's battered and rebuilt breakwater reflects the ongoing struggle to create an infrastructure capable of withstanding one of India's most challenging coastal environments. At the same time, the sandwiched strip of land north of the harbour highlights the human cost of living on the edge, where every storm and rising tide brings uncertainty and risk.

While progress is evident - seen in the near completion of the extended breakwater and continued efforts to fortify the harbour - the challenges for the region remain far from over. The stories of damaged roads, destabilized homes, and relentless wave energy reveal that engineering solutions alone are not enough. A broader, more holistic approach is needed, one that combines infrastructure improvements with strategies to address the vulnerabilities of the surrounding community.

Thengaipattinam's story is a microcosm of the wider challenges faced by coastal communities across the globe. As the forces of nature grow stronger with climate change, the lessons learned here - about adaptation, resilience, and the need for sustainable solutions - will be vital for navigating the storms ahead.

1. Sanil Kumar, V., & Anoop, T. (2015). Wave energy resource assessment for the Indian shelf seas. Renewable Energy, 76, 212-219. https://doi.org/10.1016/j.renene.2014.11.034

2. Sirko, W., Brempong, E. A., Marcos, J. T., Annkah, A., Korme, A., Hassen, M. A., ... & Quinn, J. (2023). High-Resolution Building and Road Detection from Sentinel-2. arXiv preprint arXiv:2310.11622.

3. Planet Team (2025). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://api.planet.com