Asian Tsunami: Lessons from the SurvivorsWhy coral reefs and mangroves protected and saved many lives and concrete structures succumbed and could not protect? When the devastating tsunami struck several nations around the Bay of Bengal and the Indain Ocean on the 26th of December, 2004, areas covered with coral reefs and mangroves did not suffer much damage and protected the people inland. On the other hand, many buildings, resorts, an air force base, highways and bridges and other concrete structures collapsed. Can man-made structures ever be substitutes for nature? | |||||||||||||||||||||
When the Tsunami washed away the lives and livelihood of more than 2 lakh people in Southern Asia, it also washed away many man made structures including buildings, resorts, highways, houses and even an Indian Air Force base at Car Nicobar. But in areas where there were extensive coral reefs and intact mangroves, the loss of lives and damage appeared to be much less than those where the reefs had been damaged and the mangroves ripped out and replaced by prawn farms and poorly planned beachfront hotels. While the coral reefs and mangroves savedthe land and its people, concrete structures succumbed and killed many inmates
Man made structures could not withstand the fury of the tsunami, nor did they protect lives. Some deaths have been attributed to injuries sustained from these structures collapsing over inmates.
The coral reefs and mangrove swamps are double barrier of defence that nature provides against catastrophes from the sea. Mangroves, coral reefs and coastal forests together act as a 'protective screen' for the coastal system. The solid barriers of the reefs brake up and slow down the waves while the tangled roots and dense vegetation of the mangroves absorb much of their remaining energy.
Mangroves grow in thickets along tropical coastlines between the high and low-water marks. Mangroves act as natural shock absorbers, dissipating the destructive wave energy and buffering against erosion. The first layer of red mangroves with their flexible branches and tangled roots hanging in the coastal waters absorb the first shock waves; the second layer of tall black mangroves then operates like a wall withstanding much of the sea's fury. The volume of water reaching a point is greatly reduced since tsunami water, after entering into the mangroves, is distributed to all the canals and creeks that are present all over the mangroves. Their complicated dense root and branch structure efficiently bind the soil of the shore together and also trap the sediment in their roots, giving the seabed a shallow shape. This absorbs the energy of waves and tidal surges, protecting the land behind. Mangroves help to protect offshore coral reefs by filtering out the silt flowing seawards from the land. Mangroves in addition absorb more carbon dioxide per unit area than ocean phytoplankton, a critical factor in global warming. Trees along the coastline act as wave-tamers and form a barrier against wind. Tragically, the full fury and wrath of the tidal waves were felt in areas where nature's green belts of coral reefs and mangroves no longer exist or were never present in the first place. Things might have been different had healthy mangrove forests, coral reefs, sea grass beds and peatlands been conserved in a healthy state along these coastlines. These vital protective buffers against wind and wave had been foolishly degraded or removed for unsustainable development. In many parts of the affected areas where dense mangroves and coral reefs have been replaced by townships, hotels and tourist resorts, golf courses, industries and shrimp farms (mainly to supply Western tables), transport infrastructure and coastal highways, housing, mansions, commercial developments and refineries. The neo liberal economic policies that pushed economic growth at the expanse of human life has contributed in no small measure to exacerbate the magnitude of the disaster. Large areas of coral reefs in the Indian Ocean region have suffered extensive damages due to climate change and human activities - waste water from new developments, dynamite fishing, sewage pollution, quarrying for building material and warmer water because of climate change. Only a third of the world's coral reefs remain healthy and one-fifth of them have been destroyed completely. Half of the remaining reefs in the Indian Ocean are at risk. Since the 1960s, the Asian sea-coast region has been plundered by the large industrialised shrimp firms (largely funded by the World Bank). Nearly 72 per cent of the shrimp farming is confined to Asia: grown tenfold in the last 15 years, it is now a $9 billion industry. The expansion of shrimp farming was at the cost of tropical mangroves. Each acre of mangrove forest destroyed results in an estimated 676 pounds loss in marine harvest. Up to half of the world's mangrove swamps have disappeared in the last 20-30 years. Indonesia had lost over 30 percent of its mangroves over the past 20 years, Thailand 50 percent, while Sri Lanka even more depleted. In India, mangrove cover has been reduced to less than a third of its original in the past three decades. Between 1963 and 1977, the period when aquaculture industry took roots, India destroyed nearly 50 per cent of its mangroves. Local communities were forcibly evicted to make way for the shrimp farms. Whatever remained of the mangroves was cut down by the hotel industry. Tourism boom in the Asia-Pacific region coincided with the destructive fallout of the growth in shrimp cultivation. Tourism growth, whether in the name of eco-tourism or leisure tourism, decimated the mangroves and destroyed the coral reefs. In the past two decades, the entire coastline along the Bay of Bengal, Arabian Sea, and Strait of Malacca in the Indian Ocean and all along the South Pacific Ocean has been a witness to massive investments in tourism and hotels. Myanmar and Maldives suffered very less from the killing spree of the tsunami because the tourism industry had so far not spread its tentacles to the virgin mangroves and coral reefs surrounding the coastline. The massive wave of destruction caused by the Dec 26 tsunami in 11 Asian countries alone has surpassed the economic gain that the shrimp industry claims to have harvested by several times. With over 1,50,000 people dead, the staggering social and economic loss will take some time to be ascertained. The fact that the natural barriers saved many lives should be a valuable lesson for all governments. Coastal zones and green belts such as mangroves, coral reefs and other natural barriers must be protected, regenerated and managed in a sustainable way. Attention should be paid todeveloping mangroves rather than building 'hi-tech' warning systems M S Swaminathan, one of India's leading scientists, says that the world leaders should be paying even more attention to developing mangroves and other natural barriers than to a tsunami early-warning system. High-tech warning systems may be of little value when tsunami is generated, for though a warning could certainly save lives by giving a chance for tourists to get off the beaches and local people to head inland, it would do nothing to prevent wholesale destruction. On the other hand, it simply is not practical or economic in most cases to rebuild houses and infrastructure with the structural strength to withstand tsunamis. If the return period of events like this is 50 to 100 years, it is beyond the lifespans of most of the people involved and certainly longer than the life of most buildings in the tropics. Therefore, it is only through having such natural defenses that coastal communities can be protected in the long run. Tsunami defense preparations should include a range of coastal restoration projects including mangroves, sand dunes and indigenous fringe forests. Nature's furycan only be countered bynature! Indonesia has already decided to replant huge swathes of mangrove forest along its vulnerable coastline. The government of Kerala state in India, observing that the tsunami left less destruction in regions protected by mangroves than barren and exposed beaches, has already started a project for insulating coasts with mangroves. Nature's fury can only be countered by nature. As one of the fishermen said, "we saved the mangroves by restoring them and it saved our life and property by protecting us" Compiled for Back2Cradle By: B.S. Kakkilaya Source: http://www.back2cradle.org/tsunami3.htm |
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