January 09, 2005
The life [(or lives) saved by] aquatic [vegetation]Science
There's the high tech approach to minimizing tsunami deaths -- a global alert system that tries to predict tsunamis -- and then there's the low tech approach -- mangrove swamps. This should not be a surprise - wetlands are very effective at combatting flooding, for example, far more so than levees and dams. And while it is anthropomorphic to say that "the wetlands are nature's method of protecting people," it is useful to observe that wetlands have preserved many lands and try to cultivate them for that purpose. The Christian Science Monitor reports [snippets only]:
Mr. Selvum says that 172 families were saved from the tsunami in the fishing village of Thirunal Thoppu in India's Tamil Nadu state only because the mangroves are thriving and dense there. He also mentions three other Tamil Nadu villages where damage had been minimized by the aquatic trees. "Every village has more than 100 families, so just think of the number of lives saved," he says."Even though the mechanical impact of a tsunami is enormous, and is bound to destroy the first line of mangroves, the water suddenly slows down as it moves farther in," Selvum says.
According to Sridharan, mangroves form only 62 miles of the 620-mile Tamil Nadu coastline. If well looked after, they could save thousands of lives if their density is at least 70 percent in places. "They must be grown very thickly together to have any use as barriers," Sridharan explains.Bittu Sehgal, a feature editor and ecologist at Sanctuary magazine, told the Indian Express newspaper that he firmly believes the famous mangrove reserve of the Sundarbans in West Bengal saved the coastal part of the state from severe losses.
"The forest officers on duty have reported there that the water level rose by three to five feet when the tsunami hit. But this is nothing abnormal as we can see 10- to 12-foot high tides on the Sundarbans coast. The mangroves saved us," he says.
Environmentalists say that to focus exclusively on mangroves would be a mistake. "We need many more coastal shelter belts that stop the intrusion of salt water, like casuarinas and acacia trees," says Selvum. "But, as usual, it is very late in the day." [CSM]
ennis on January 9, 2005 08:01 PM in Science · T·r·a·c·k·b·a·c·k address · Direct link · Email post
¤ Winds of Change.NET said: The Simplest Tsunami Defence
Sounds good. Maybe one of the NGOs with actual boots on the ground could pick it up.
But wouldn't the biggest issue be land onwership?
Wouldn't something like a mangrove wetland would be a "commons" and therefore subject to conflicting priorities of the owners?
Is there any effective "state parks" kind of program in the Indian Ocean contries that could be a local model to follow?
Since many of the area affected are resorts, can you have simultaneous beaches and mangroves areas?
- Adriane
Of course, this conflicts with interests in having beaches, which are terribly popular.
