There is this apocryphal story: a woman activist happened to spot a tractor levelling a mound on Elliot's beach. Jumping into action, she climbed into the machine, pulled the ignition key out and flung it far into the Bay of Bengal. Turning to the stunned driver she said the “bump” he wanted to flatten was actually a sand-dune; it stopped seawater from entering the land. The mound has since survived.
“That mound was probably a dune filled with gravel for stability,” said marine biologist T. D. Babu. “Dunes get shifted unless they harbour vegetation. Which is why sand routinely gets deposited on the Elliot's beach promenade. Left undisturbed, it may form a dune right there!” “Want to see a beautiful dune specimen,” he offered. “We'll leave at 6 a.m. tomorrow.”
Babu was determined to educate me on sand-dunes. Do you realise we're moving up and down, he asked, as we drove down the ECR. I did, I said, and admitted I hadn't noticed it the dozens of times I'd taken the road. These were dunes, he said, pointing to the steep dip into sandy stretches on the sides as proof. At the Kapaleeswarar arch we turned towards the sea, drove to the road-end and stopped. A sandy slope took us to the beach. There we turned around to take in the magnificent, green-carpeted dunes stretching for miles on either side. “The tsunami devastated Karikattukuppam, a fishing hamlet,” he continued. Catastrophic waves crushed concrete houses, and the fishermen fled to safety. “The Karikattukuppam residents had demolished the dunes to extend their village to the sea. But Jambalodai, just a km away, escaped huge damage because of its location behind large dunes.” This is not apocryphal, he added.
We walked down the coast, taking pictures. “These sand-dunes act as non-bio-shields and protect coastal creatures such as turtles from predators’ sight,” the lesson went on. “They are coastal aquifers, preventing salt intrusion into groundwater. How come Besant Nagar had sweet borewell-water in spite of being so close to the sea?” No more, he sighed, over-extraction and flattening of dunes have made groundwater salty. Don't miss the coastal creepers, he said, identifying the greenery on the dunes. Plants such as ipomea and spinifex littoreus (the spiky Ravan's moustache) are green armours that hold dunes from getting eroded by wind and water. Grazing animals keep away from these hyper-salty treats, but insects find food in the flowers and, in turn, attract coastal birds. Why don't we recognise their role in disaster management, he tut-tutted. They stop sea erosion, increase shore-slopes, reduce the intensity of cyclones, prevent inundation, and mitigate the effects of tsunamis and floods. Ignorance, I offered.
We reached the seaside of a well-known resort. He pointed to a lotus pond inside the fenced area. “That could be a dune-slack, a low-lying area within the dune system that gets seasonally flooded.” Here we found swathes of ipomea and spinifex, pandanus ( Thazhambo ) and coconut trees. “Others are borassus ( Panaimaram ), Thespesia populina ( Poovarasamaram ) and pongamia ( pongamaram ),” he said, “all of which reduce the impact of storms/cyclones, and form bio-fences against sand-dune shifts. Also, native coastal vegetation provides a livelihood to coastal communities.”We crossed the resort and stopped in shock at an unsightly scene. Dumped on the pristine sand were broken tiles, acres of garbage, and a stinking canal of dishwater. Clear tyre-marks told their story. More alarming was an artificial hill of rubbish, wrapped in sea-creepers. A cover-up! “Building of tourism/recreation facilities, housing, parking-lots, roads and other infrastructure, and mining, degrade/flatten coastal sand-dune habitats. Coastal protection structures such as seawall and groynes affect sand movement, leading to heavy erosion and accretion along the coast. These change the shoreline pattern, affect natural formations, and lead to loss of species diversity.”It’s 9 a.m., end of lesson, and show-off time for me. “At Cheyyar, the dunes are massive, spreading over miles,” I said. “So huge, they have created fresh-water ponds on the land.” Thanks to them, farmers grow grains and vegetables close to the sea, households in sea-side villages pump out salt-free fresh water and the java-plum (naval-pazham) trees bear the sweetest fruits you can taste. Here, a range of hilly sand-dunes breaks the salty breeze to create an agricultural Eden on its landward side.
