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Shifting sands
The boundary between the land and the sea is sacrosanct to humans, as they build their lives close to this real but constantly changing line. But the line has become even more fickle, thanks to human activities — placing artificial barriers in some areas have had unintended consequences for others. The enviable second longest coastline from the Marina, extending south of the city, is its latest obvious victim as erosion is eating away not just at the sands but also at lives, homes, and livelihood
Groynes that the Tamil Nadu government has built to prevent coastal erosion at Soolerikattukuppam village in Chengalpattu district. However, groynes merely shift the erosion from one village to another, say experts.
| Photo Credit: B. VELANKANNI RAJ
Tamil Nadu, with the second longest coastline in India at 1,076 kilometres, has long thrived on its rich maritime heritage. Its coast has been the cornerstone of the State’s prosperity for ages. Yet, as climate change drives up the sea level, the boundary is shifting between the land and the sea.
Erosion eats away at the coast, threatening the livelihood of fishers and others who have made their homes there. Development projects, intended to bolster economic growth, and ‘solutions’ to prevent sea erosion are only worsening the situation by altering the shoreline and compounding the challenges faced by local communities.
To deal with sea erosion, it is crucial to understand how the coast erodes in Tamil Nadu and examine the specific vulnerabilities of the State’s coastline. Sea erosion happens when the shoreline wears away by the movement of sand and water. In Tamil Nadu, for most of the year (about eight months), the wind and the sea current flow from the south to the north, carrying sand along with them. During the northeast monsoon (for about four months), they reverse their direction.
When hard structures like ports, breakwaters, or groynes are built extending to the sea, they block the natural movement of sand. As a result, sand piles on one side of these structures, and the opposite side loses sand and begins to erode. This imbalance accelerates coastal erosion on the side where sand is no longer deposited, causing waves to advance further inland and increasing the risk to the coastal areas.
How vulnerable is the coast?
A study conducted by Anna University’s Centre for Climate Change and Disaster Management reveals that 76% of the coastline in Chennai, Tiruvallur, and Chengalpattu, running to 102.2 km, is at risk from cyclones, coastal erosion, and the sea level rise. Tiruvarur, Nagapattinam, and Chengalpattu are especially vulnerable, owing to high salinity and low elevation. Over 60% of the coastline in Kanniyakumari, Chennai, and Cuddalore is also exposed to climate change, influenced by land use and infrastructure.
The National Centre for Coastal Research (NCCR) reports that 422.9 km (42.7%) of Tamil Nadu’s mapped coastline of 991.4 km is facing erosion, exacerbated by hard structures such as groynes, jetties, and piers, with the number of these structures increasing since 2022. Tiruvallur and Kanniyakumari have the largest proportion of their coastal areas occupied by ports, harbours, and coastal protection structures, according to the NCCR. Over the past five years, the fisherfolk of Karikattukuppam, a coastal hamlet near Muttukadu in Chengalpattu district, have observed the sea inching closer to their homes. During cyclonic storms and on full and new moon days, they have had to watch over their boats and fishing gear. This situation is common in several villages across Chengalpattu.
Do groynes prevent sea erosion?
In response to the fishing community’s concerns, the Fisheries Department in 2023 applied its standard solution: groynes. Unfortunately, this approach has led to significant challenges for villages north of Karikattukuppam, like Reddy Kuppam in Kanathur. Fisherfolk of Reddy Kuppam have had to move their boats to Karikattukuppam, where two groynes offer temporary shoreline protection.
A private beach resort at Muttukadu, adjacent to Karikattukuppam, is also in peril. Over the past six months, its beach has almost disappeared. To safeguard the remaining shoreline, the resort has placed boulders along the coast, in violation of the Coastal Regulation Zone (CRZ) rules. Some individuals who have constructed bungalows along the coast are also placing boulders in front of their houses without obtaining the CRZ approval. But their circumstances leave them with little choice, they say.
Meanwhile, they continue to suffer from erosion, hoping that the State government will build groynes or seawalls to protect their homes and livelihood. However, groynes merely shift the erosion from one village to another. Multiple groynes placed in each of the six villages in Chengalpattu district recently has initiated a chain reaction of adverse effects whose full impact is yet to be fully understood.
Reliable experts point out that the single factor that accelerated sea erosion in the villages north of Nemmeli, Chengalpattu, is the desalination plant, construction of which began in 2013, causing immense damage to the nearby Soolerikattukuppam village. Further south of Nemmeli, rapid expansion of prawn hatcheries has exacerbated the problem.
Port expansion
In Tiruvallur, Tamil Nadu’s northernmost district where the Ennore Port and the Adani Kattupalli Port have caused immense damage to the coast, fishing villages along the East Coast Road between Kattupalli and Pulicat face the threat of sea erosion even as the expansion of the Adani Kattupalli Port looms over the hamlets. Punitha, a resident of Koraikuppam, says the situation remains precarious and she has little faith in a seawall. “As fisherfolk, we understand the true force of the sea. A wall can’t keep it at bay,” she says.
Despite numerous studies and evidence indicating that groynes are ineffective, the State government continues with them. For example, in response to a recent question posed by Lok Sabha Member V. Vaithilingam about protecting coastal communities in the southern States, the Ministry of Environment, Forest and Climate Change stated, “The fishing harbours and fish-landing centres developed under these schemes include essential waterside and landside facilities, such as breakwaters, training walls, and groynes. These structures are designed to provide shelter and create a calm basin for smooth fishery operations and to protect the lives and assets of fishermen during rough weather and natural calamities.”
Have the groynes been useful for the fishers? Yes and no. Uma, a fisherwoman from Chemmencheri Kuppam near Kovalam, notes that the groynes help to keep waves out of her village for now. However, she points out that the groynes should have been extended further into the sea. As it stands, fishermen are unable to launch their boats because the waves crash against the ends of the groynes.
Fishermen of Karikattukuppam echo these concerns. Further, the residents of Pudu Kalpakkam at Nemmeli, where a new breakwater built for the 400-MLD desalination plant under construction has also exacerbated erosion in villages north of it, feel that instead of six groynes, the authorities could have built four groynes in a slight curve. This would have facilitated an easier access for boats to the sea.
After a petition, filed by K. Saravanan, a fisherman and activist from Urur Kuppam at Besant Nagar, Chennai, against the construction of groynes was heard by the Southern Bench of the National Green Tribunal, it came to be known that they were built without CRZ clearance from the Tamil Nadu State Coastal Zone Management Authority (TNSCZMA).
Trouble in Puducherry
The negative effects of hard structures are well known. Since 1989, Puducherry’s beach began disappearing due to severe sea erosion caused by a port disrupting littoral drift. The port’s construction led to sand accumulation in the southern side and erosion in the northern side. However, in 2017, a beach nourishment project, taken up by the Puducherry government along with the National Institute of Ocean Technology, successfully restored the beachfront on the Promenade, benefiting both locals and tourists.
But the problem in Puducherry is far from over. In 2023, erosion was reported in the southern side of the Promenade. Officials are now conducting research to ascertain the best possible way to restore the beach.
The NCCR has completed a thorough assessment of the Tamil Nadu coast and developed a shoreline management plan, which will outline measures to safeguard the coast from sea erosion. NCCR Director M.V. Ramana Murthy says the framework includes recommendations to deal with the limitations of conventional strategies such as seawalls, groynes, and training walls.
For seawalls suffering from wave overtopping or crest slumping, the NCCR recommends reforming the existing structures. In areas where groynes cause downdrift erosion or flanking — a process in which high tides or storm surges bypass the landward end of a groyne and erode a channel around it — the framework suggests using nourishment and bio-shields (coastal vegetation). Additionally, where training walls have led to erosion, filling the eroded portions with dredged sediment is recommended.
Marking out hotspots
Identifying erosion hotspots and zones is crucial for coastal protection. The Southern Bench of the National Green Tribunal has directed the TNSCZMA to include areas used by fishermen for storing nets, operating markets, and housing in the draft Coastal Zone Management Plan (CZMP), as mandated by the Coastal Regulation Zone Notification, 2019.
Since 2022, fisherfolk have been objecting to the CZMP as there are discrepancies in the marking of no-fishing zones, fish breeding areas, and fishing grounds. Furthermore, the Tiruvallur fishing community has requested that the district be designated as a high-erosion zone owing to the extensive damage caused by ports and their breakwaters. “In an erosion hotspot, construction may not be recommended. It’s not that nothing should be built, but a structure put up there should not magnify the problem. The whole objective must be to analyse the coast, see the sensitivity and the anticipated impact, and how we can mitigate them,” says Mr. Ramana Murthy.
Hybrid method
Rahul Nadh, Director, Department of Environment, and Member-Secretary of the TNSCZMA, says erosion zones, fishing grounds, and turtle nesting grounds have all been incorporated into the revised draft CZMP, and it will be released shortly.
“The shoreline management plan, prepared by the NCCR, contains details of erosion zones. In place of hard structures, a hybrid method of having a combination of hard and soft structures has been recommended,” he says.
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