“The disappearing beach dilemma” was the title of an article in the November, 2002 issue of Auroville Today. In it Aurofilio Schiavina, who has studied coastal management, warned of the imminent loss of Auroville’s beaches due to “unsustainable development practices in Puducherry”.
He was referring to the construction of two long breakwaters to the south of Puducherry town in the late 1980s as part of a new port development.
These breakwaters had blocked the sea's natural transport of sand up and down the coast (known as ‘littoral drift'), causing a massive build-up of sand to the south of these structures and fierce erosion of the beaches to the north. In 2002, the writing was already on the wall. In little more than a decade Puducherry had lost its beach and villages to the immediate north were losing theirs. The Auroville beaches, Filio warned, “face the prospect either of being washed away or needing protection by massive seawalls to prevent an erosion disaster”.
In addition to their recreational benefits, beaches are an essential part of the coastal ecosystem. A substantial beach is a valuable protection against storms and tsunamis and it prevents seawater intrusion into coastal aquifers. To counteract the erosion, Filio and other concerned individuals persuaded the Puducherry Government in 2002 to resume dredging of the harbour mouth at Puducherry and to undertake sand replenishment activities at the affected sites. “As a result, some beaches started to reappear in Puducherry, but because sand nourishment was undertaken only sporadically and not to its full requirement, the erosion could not be fully controlled. At the same time they also convinced the Puducherry Government to shelve the project of constructing a ‘groyne field' (a series of seawalls built perpendicular to the shore, projecting seawards for about 100-150 m in length (see box) in front of the Puducherry seafront. Such a groyne field would have meant transferring the problem of erosion to the Tamil Nadu coastline to the north and the onset of massive and accelerated erosion along the Auroville beaches.
“Then in 2004 the tsunami hit this coastline and the whole situation went out of control. Subsequently the Government started talking of shoreline protection and large sums of money were made available for constructing and strengthening seawalls. The whole situation was so ‘emotional' during that period that it was not possible to have a reasonable dialogue with the Government agencies to take up environmentally-sound coastal protection measures.
“So the Puducherry seawall was extended, causing the erosion to move north to villages in Tamil Nadu. As these villagers' homes were washed away by the intruding sea, they sought the intervention of the Tamil Nadu Government.
Instead of addressing the root cause of the problem – the blocking of littoral drift by the breakwaters at the Puducherry port – the Tamil Nadu government also built seawalls. However, because seawalls do not help retain sand but only protect the land from further erosion, the fishermen lost their beaches – where they park their boats, repair their nets, and dry the fish – as well as their access to the sea.
“Thus the livelihood of these communities was severely affected and they wanted their beaches back. The authorities, once again, failed to tackle the root cause of the problem. Instead, they now started to build groynes in an effort to retain some sand. But the construction of seawalls and groynes accelerated the rate of erosion further north and more villages were severely affected. Several homes even disappeared into the sea.
“The first groynes were small, but this April much longer groynes were built on either side of Thandirayankuppam village. For the beaches and communities north of Thandirayankuppam the construction of such long groynes are a disaster because they have started a whole new cycle of accelerated erosion in places like the Auroville beach community of Quiet (see accompanying article). Meanwhile, the three shorter groynes built in Kottakuppam closer to Puducherry are being lengthened, which will accelerate and extend even further the erosion to the north.
“Today, sand erosion affects about 25 kilometres of the coast to the north of Puducherry and has severely damaged a 7 kilometre stretch. The erosion is moving northwards at about 350 metres a year.”
Erosion caused to the north of the groyne nearby Quiet. The bush has meanwhile disappeared into the sea.
The new port project
Can things possibly get worse? Filio says they can. “For now the Government of Puducherry is planning a big expansion of the port – ten times the size of the existing harbour – which will include constructing a new breakwater 2.5 kilometres long to create a large harbour.” While the Environmental Impact Assessment report concerning the proposed new port development states that “the proposed development of the new port will not cause the current situation to worsen”, Filio is skeptical. “Chennai, which has similar coastal geomorphological features to the Puducherry coastline, has a harbour similar to that proposed in Puducherry. By comparing the huge erosion the Madras harbour has caused to its nearby northern coastline, one can anticipate what is in store for the beaches to the north of Puducherry if such a harbour is built.”
Recently, the environmental magazine Down to Earth featured the proposed new Puducherry port development plan. The lead article, which was highly critical of the project, concluded that “The construction about two decades ago of the commercial harbour and breakwaters south of Puducherry was the beginning of the end for the beaches that dotted the coast of Puducherry and Tamil Nadu. The new port promises to finish the job comprehensively.”
What can be done?
Filio is very clear. “The proposed port development should be dropped. Full-time dredging at the existing Puducherry harbour and sand replenishment activities at the affected beaches to the north should be resumed immediately. The construction of groynes should be stopped.
Only essential and temporary coastal protection measures to prevent people's homes from getting washed away should be adopted. At the same time, a study of this coastline should be undertaken and short-term and long-term coastal management measures should be established.”
The best coastal protection measure is a healthy coastal ecosystem, notes Filio. “Our coastline here is characterized by dunes and estuaries. Dunes are a very effective barrier and they also serve as temporary reserves of sand. But for dunes to exist you also need certain types of vegetation on them. So a healthy dune ecosystem will have dunes as well as vegetation. Where you have estuaries you have mangroves and mangroves also offer protection and stabilization of the coastline. The problems start when we interfere with these ecosystems and we upset the equilibrium that nature has established over millennia.”
This is precisely what is happening at present, and it is typical of what is happening elsewhere in India and in many other parts of the world. “While it is true that one cannot stop development and development is bound to have some impact on the environment,” observes Filio, “in cases like this, it is the non-implementation of mitigation measures that aggravate the problem.”
Photos of the beach hut outside Quiet taken within a span of 7 days.
Will there be action?
How optimistic is Filio that the political will exists to resolve the problem of coastal erosion in this area? “Local communities in Tamil Nadu that are already facing the problems of coastal erosion have passed resolutions demanding that the proposed port project be dropped and that sand nourishment activities be started immediately. However, the political will to solve this problem is totally absent, mostly due to lack of awareness. Moreover, as the Down To Earth article made clear, the interest in the real estate development attached to the port project is overriding all environmental considerations. So perhaps the only hope is that the judiciary might force the politicians to change their course of action. In fact, a few civic groups are already preparing to take the Puducherry government to court, alleging negligence over their failure to resume sand dredging operations.”
A groyne is a rigid structure built out from the shore which interrupts the flow of water and sediment. The purpose of a groyne is to create and maintain a healthy beach on its updrift side, which in turn provides protection to the land behind. These effects are achieved through two main processes. First, groynes act as a barrier to physically stop sediment transport in the direction of longshore transport through the system. This causes a build-up of the beach on the groyne's updrift side. Secondly, groynes interrupt the tidal flow forcing the tidal current further offshore beyond the groyne end. This slows the tidal current inshore causing the deposition of heavier sediments and encouraging the beach to grow in size.
However, this is often accompanied by accelerated erosion of the downdrift beach, known as terminal groyne syndrome, as it occurs after the terminal groyne which receives little or no sand via longshore transport. If a groyne is correctly designed, then the amount of material it can hold will be limited, and excess sediment will be free to move on through the system. However, if a groyne is too large it may trap all sediment reaching it and this can cause severe beach erosion problems on the down-drift side, which in turn can result in coastal erosion problems.
It's an ill wind…
Puducherry's loss is Cuddalore's gain. While the breakwaters of Puducherry port are starving the northern coast of sand, they are causing sand to accumulate to the south. Cuddalore, about 10 kilometres to the south of Puducherry, now has a much bigger beach. In fact, recently they held their first beach festival.
It's not well-known that even the famous Marina Beach in Chennai is the result of the British building a harbour and breakwater to the north in the late 19th century.