Tag Archives: littoral drift

Dredging the Ariyankuppam River Mouth

Chief Minister Rangasamy Inspecting the Dredging of the Ariyankuppam River Mouth
Chief Minister Rangasamy inspecting the dredging work of Ariyankuppam River mouth
— Photo: T.Singaravelou, The Hindu, 27 February 2008

Chief Minister N. Rangasamy on Tuesday reviewed the dredging work of Ariankuppam river mouth to facilitate free movement of vessels to the fishing harbour.

On 26 December 2007, the Port Department of the Government of Pondicherry inaugurated the TSD Sindhuraj, a dredger owned by the Kerala State Maritime Development Corporation (KSMDC), to dredge the mouth of the Ariyankuppam River, presumably as a “beach nourishment” measure.  Banners put up at the “New Pier” (built in 1989) where the inauguration ceremony took place claimed:  “Beach Nourishment Activity due to DREDGING at Pier” and “Beach Nourishment Activity due to DREDGING at Northern Groyne.”

“Beach Nourishment” Poster
Government disinformation banner

Because the New Pier interrupts the littoral drift (the natural movement of sand along the coast), sand accretes (accumulates) to the south of the pier (and blocking the mouth of the Ariyankuppam River at the north groyne of the harbour) and is eroded north of the harbour.  Engineers predicted this problem when the New Pier was being designed and suggested continuous dredging to pass the sand from south to north of the pier.  However, maintenance dredging was not done on an annual basis, resulting in the loss of over seven kilometers of beach in Pondicherry.

As per the agreement signed between Puducherry Government and KSMDC on November 7, 2007, which operates the Dredging Corporation of India’s dredger TSD SINDHURAJ, would de-silt one lakh cubic metres of sand deposited in the river mouth by the end of March this year.

Two months after the inauguration, the stated reason for the dredging has changed from “beach nourishment” to “facilitate free movement of vessels to the fishing harbour”, as reported in the Hindu article quoted in this post.

As per the agreement, the territorial administration has to pay a fee of Rs 2.87 crore to desilt the harbour.

With Tsunami money to be spent by the end of this fiscal year (March 2008), the Port Department hired the TSD Sindhuraj, a shallow drag suction dredger, at a cost of over US$ 735,000, to remove 100,000 cubic meters of sand.  This is being done to enable the trawlers owned by corporations and politicians to access the fishing harbour.  The local fishermen have no problems getting out to sea and back in their traditional boats.

Officials said the vessel had so far made 287 trips to dump the dredged sand about 4 kilometres away from the Ariankuppam river mouth.

Citizens of Pondicherry requested that the sand that was to be dumped out at sea south of the pier, be taken closer to the beach north of the pier to replenish the coast.  The Port Director claimed that because of the design of the dredger, the boat could not come closer than 4 meters, but agreed to send the TSD Sindhuraj to release the sand at 4 meters.   However, even that was not done.

According to an abstract of the ‘Outline of the drag suction dredger “TSD SINDHURAJ”‘:

This ship is planned with the fully loaded [capacity is 200 cubic meters] draft of 2.0 m to dredge the shallow sea beds of small fishing ports in India, and is equipped with a submersible auxiliary pump at the bow to dredge shallow sea beds. It has 2 motors, 2 shafts, and 2 rudders for maneuverability.

Surely some attempt could have been made not to waste even this drop-in-the-bucket amount of sand.

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Meeting on Restoration of Pondicherry and Tamil Nadu Coastline

 

A consultation meeting of scientists, technical experts, representatives from Tamil Nadu and Pondicherry administration and NGOs was organized in Auroville (Tamil Nadu) on Saturday, November 3rd, 2007. The meeting was jointly organized by Auroville Coastal-area Development Centre (ACDC) and Pondicherry Citizens Action Network (PondyCAN).

Introduction:

Since the late 1980s the coast along the town of Pondicherry and the neighboring areas of Villupuram district in Tamil Nadu to the north has been eroding. In the last decade, the erosion has worsened and continues to progress northwards. Ten kilometers of the beach has completely disappeared and as the erosion to the north continues, about 30 km of coastline in Pondicherry and Tamil Nadu has been affected.

More recently, the process of erosion has accelerated and many traditional fishing communities have not only lost their livelihoods but also their homes.

Conclusions from the Meeting:

It was unanimously agreed by the experts gathered at the meeting that the cause of the erosion is the fishing harbour that was built at Aryiankuppam in 1989, which interferes with the littoral drift that results in the net movement of 0.5 million cubic meters of sand northwards each year. Badly planned groynes, built to protect rapidly disappearing fishing communities, have accelerated the erosion.

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