Coastal protection and restoration: can we learn from Pondicherry?

Auroville Today: In the past year, and particularly in the last few months, there has been serious erosion of some of the southern Auroville beaches, particularly Quiet and Samuthira (formerly Mira Youth Camp) leading once again to loss of buildings. Some people believe that the work going on in Pondicherry to restore the beach there is contributing to this. Is this a possibility?

Filio: In theory, yes, but it is highly unlikely. Firstly, what looks like a groyne near the Ashram tennis ground has only been there since June this year. It was constructed to build a submerged onshore reef and while it is there it will block the transport of some sand to the north. However, it is only temporary and once the reef is built, the blockage will be removed.

Moreover, this ‘groyne’ is too far away from the Auroville beaches for the impacts to show there in a matter of a few months. If we take the case of Repos, it took 4-5 years for serious erosion to set in after a groyne was constructed at Thandirayankuppam village only one kilometre away. Our construction is much further away from the southernmost Auroville beaches.

So if there is any negative impact from the temporary ‘groyne’, it will be short and felt only locally (a few hundred metres north of the reef), and most certainly not as far as Quiet and Repos, particularly in such a short time.

Once the reef is in place, initially it will hold back some sand. This is because it is designed to ensure that the Pondicherry beach is restored. But once the beach is restored, the reef will be submerged and even buried underground and thereafter sand will flow freely above it.

How long will this take?

If everything goes well, we are talking about one to two years for the beaches in Pondy to be restored and four or five years for a trickle-down effect to the Auroville beaches which will be benefited from sand flowing north.

There will also be a second reef, but this will be an offshore reef opposite the Hotel Ajantha on the Pondicherry seafront. The purpose of that reef is to slow down the sand going back into the Pondicherry harbour: it will not impact the Auroville beaches at all.

If the new Pondicherry reef construction is not to blame for the accelerating erosion of some Auroville beaches, what is the explanation?

There is always natural variation in the width of beaches: any normal beach will vary by ten or fifteen metres in a year. Actually, I think that Repos and other Auroville beach communities to the south were lucky during the previous two years because the erosion was much less severe than one would expect with a groyne and a seawall nearby. I’m not sure about this, it has to be confirmed with some data, but in 2013 we got the Pondicherry government to nourish one and a half lakh cubic metres of sand in the sea which had been stacked up on the land at the port.

The most plausible explanation is that this sand traveled north to the Auroville beaches and delayed or mitigated the erosion there. But now that the supply is exhausted, the normal speed of erosion has resumed.

There has also been a vigorous south-west monsoon this year, resulting in a constant wave action since April. So if you put together a reduced supply of sand and increased wave action this would result in increased erosion.

What would you advise? What can the affected Auroville communities do? They are losing land fast.

I completely empathize with them, it is easy for us whose houses are not being washed away to advocate the ideal solution and there is clearly an urgent need to do something. But at the same time, it is equally hard to agree to suggest some unscientific, piecemeal, short-term, ad hoc measure that will finally result in an increase of erosion, especially to the neighbouring beaches. The Indian coastline is densely populated and there are no uninhabited beaches that can be sacrificed at the cost of inhabited ones. Transferring and increasing erosion to the neighbouring beach also impacts the lives of others.

Last year you advised intermediate solutions that do not cause any more damage to the shoreline. These would include beach nourishment and the employment of the least intrusive protection structures.

I’m aware that many Aurovilians who are losing their homes due to the eroding coast favour seawalls to protect the seafront properties. It’s true that seawalls offer some protection and they are the least intrusive of the ‘hard’ options right now but I don’t want to recommend them because then there would be a seawall building spree.

Also, they don’t bring the beach back and, while they may protect a particular property, they accelerate the rate of erosion of the next unprotected beach. If you build a seawall or a groyne all you are going to do is transfer the erosion problem further up the coast. So you are not really fixing anything this way. The only solution that makes sense is to address the root cause.

Which is?

The Pondicherry harbour breakwater that interrupts the natural flow of sand. This is why Pondicherry lost its beaches; it is why you in Auroville are also losing your beaches.

But you have not succeeded in removing the breakwater.

True. But we in PondyCAN realised there is no point holding on to a position which ignores the existence of the harbour. For the time being, we have to acknowledge it is there and do the best we can. In the present situation, we cannot do without dredging, which also has an environmental impact, or the reefs. It is the best compromise because we insisted that any reefs being built for the Pondicherry beach restoration project should be able to be dismantled.

However, our long-term goal is to get the government to remove the harbour or, at the very least, redesign it to allow sand to flow freely again. In fact, we have managed to have inserted in NIOT’s final report the fact that the harbour needs to be redesigned.

So what are you suggesting that Auroville does now?

I think you need a multi-pronged approach. For the places under immediate threat, I would suggest using the least environmentally-destructive means of protection. Interestingly, I’ve heard that the villages outside Pondicherry are now started asking for what we are doing in the town. They are not asking for the groynes any more: they are asking for reefs and beaches. For me this is a very positive sign.

I also think you need to change your approach to the authorities. I think one of the biggest problems is that people in Auroville are not asking for beaches. Instead, they are asking for protection of the land that is in danger of erosion. But if the beaches are restored, you would have that protection too. So ask the authorities for your beaches to be restored and nourished. The how can be discussed and figured out subsequently.

Also, I don’t think there has been a concerted effort from Auroville as an institution to request the Government of Pondicherry or Tamil Nadu or Central Governments to take action. So far, it has been mainly individuals like Guy from Quiet who have been willing to do the work of contacting the authorities.

Some years ago, the National Institute of Ocean Technology (NIOT) made a study of the whole Auroville coastline but, as far as I know, nobody in Auroville asked them to take the next step, which was to come up with an action plan. That’s what we did. We stepped in and asked them to extend the study to Pondicherry and then help us draw up a plan. And that’s one reason why we have the Pondicherry beach restoration scheme.

The irony is that our association with NIOT actually started with the erosion of Quiet. In 2007, Rauf Ali had called NIOT to a meeting in Auroville, and that is when they started their coastal surveys.

How did we get to a beach in Pondicherry? We used a multi pronged approach. One approach was going to court with the help of other organizations. We tied the government’s hands over the construction of more groynes and seawalls because the Court recognized the harmful effects of these solutions, so the only option they had left was to start bypassing the sand at the harbour and restore the beaches. And we were fortunate that NIOT was not only able to come up with a solution, an action plan, but also that they were completely open to a ‘soft’ solution. So everything fell into place.

With the progress that we have made and the path that we have paved in Pondicherry, we think that today Auroville is in an even stronger position for the same to be done there.

Two reefs are being constructed, one a nearshore reef, the other offshore. The nearshore reef is a triangular steel wedge about 60 metres long and wide, and two and a half metres high. It will sit on a foundation of rocks. The top of the onshore reef will be at the level of the lowest low tide. The purpose of this reef is to restore the alignment of the shoreline to its "equilibrium profile" i.e. the shoreline profile of a stable, undisturbed sandy beach.

The intention of the offshore reef is to prevent siltation of the harbour while the nearshore reef will initially stabilize the sand so that the original beach can be restored. Once the beach is restored, the reef will be underground and sand will flow above it.

As long as the harbour continues to block the natural flow of sand, it is also necessary that artificial beach nourishment takes place. As part of the beach restoration scheme, the Pondicherry government is legally obliged to dredge a specified amount of sand annually and deposit it near the shoreline to replenish the beach. This year the requirements was four lakhs cubic metres of sand but, for various _ reasons, there was a shortfall. NIOT has now submitted a proposal to nourish seven lakhs cubic metres next year to compensate for this. The annual cost of dredging is estimated at 15 crore rupees. Filio points out that this is cheaper than the cost of coastal erosion - the loss of livelihoods, land, tourism, ecological resources and saltwater intrusion into the aquifers - or the cost of constructing and maintaining seawalls and groynes, which, in turn, cause more erosion.