Here’s why Marina is a killer

Fifteen-year-old Karthik, who lost his life on Sunday, like teenaged hockey player S Prajith on February 18, is the latest entry to the city police’s death registry: Drowned off the Marina.

Every year, the sea kills about 100 people along the 25km-long coastline from Ennore to Thiruvanmiyur. Prajith’s death prompted the Madras high court to ask the police to erect watch towers and enlist expert swimmers to protect those going into the sea. But given the deceptive nature of the city’s coastline, where rip currents pose a big threat, a small posse of police personnel, outnumbered by beachgoers, can do very little, especially when those entering the sea know next to nothing about the turbulent waters.

“A continuous coral reef [once] protected the Marina coast. It neutralised the wave energy. But the natural barrier got ruined by mechanised fishing since 1965,” said former Zoological Survey of India director K Venkataraman. With the fish gone, impurities that the Cooum and Adyar drained into the sea killed the corals.

“Coral reefs act as a buffer and soak in the impact of water currents. With no reefs on the Marina, the coastline is directly hit by the water currents,” said marine biologist T D Babu.

While coastal erosion is the direct ecological fallout, waves breaking over a naked coastline with greater impact form rip currents (see graphic) at various spots. The water pushed up along the beach recedes without any resistance, forming currents strong enough to drown those bathing.

“Even if the person is a very good swimmer, unless he has got fins on, he cannot escape,” said Venkataraman.

Scientist

Pravakar Mishra

from

Integrated Coastal and Marine Area Management

, said rip currents, wave parameters and change in bathymetry (measurement of depth of water) may lead to drowning. He said there were pockets along the coast where rip currents formed and moved away from the shore, often perpendicular to it. “Swimmers are likely to be saved and pushed back to the shore if they swim parallel to the shore,” he said.

Unlike the west coast, where the 175km-long continental shelf breaks the waves pretty early, the 35km-long shelf (25km from the Marina) on the east coast, along with the lunar cycle, renders the breaker zone dynamic. “Wave action is not uniform. It changes due to lunar and solar effects. Today, the depth could be two feet, tomorrow it could be 10 feet,” said Venkataraman. “Nobody should be allowed into the sea on full and new moon days, up to the fourth day.”

(With inputs from U Tejonmayam)