Floods are a part of nature. However, the temperature of the earth will increase due to global warming. The total rainfall will remain unchanged in India but it will rain heavily in fewer numbers of days instead of the rain being spread over 90 days as presently. Due to the heavy rains, it is necessary to increase its flow capacity of our rivers to reach the large amount of water to the sea. Only then we can save ourselves from the floods.
A report by Prakash Tripathi of “Floods Disaster in India” of Ambedkar University states that:
“The primary causes for floods are intense rainfall when the river is flowing full. Excessive rainfall in river catchments and river carrying flows in excess of their capacities.” (see report below)
The rivers deposit sediments in their riverbed every year. Then, heavy floods occur once every five to six years. At this time the silt deposited in riverbed is flushed to the sea, so that the riverbed becomes empty, and the river’s ability to carry flood water is restored.
Siltation in river can be seen as the water is interrupted
There are some positive aspects of flood. Flood water spreads every year in a large area. With this dispersion of water, the recharge of ground water is more. And hence availability of water will increase. But, in order to prevent the loss of livelihood due to the floods, we have to settle villages and cities in such a way that the water level should be low and residential areas, houses must be built on stilts and villages are built over mounds.
There is a need to minimize the damage due to the floods. This can be done by building houses at raised levels or by reducing the floods. We have taken the latter approach. We have built storage dams like Tehri, Bhakra and Sardar Sarovar to capture the flood waters and reduce floods downstream. We have also removed flood waters through barrages such as Bheemgoda and Hathnikund so that flow in the rivers and floods are reduced. In the process we have reduced the groundwater recharge and also invited heavier floods due to the sediments not getting flushed to the sea.
We must allow the floods to take place every year, so that the river’s silt can flushed to the ocean and groundwater can be recharged.
A report by Suprio Nandy of the “Center for Built Environment” says that:
The government’s anti- flood measures have actually boomeranged. Dams and embankments have now become an important cause of floods. The man-made barriers, he says, prevent drainage of excess water from floodplains into the main channels of rivers and streams. Embankments also tend to break when rivers rise suddenly, sending water gushing into the countryside. Sixteen major dams have burst in India; the worst disaster, in 1979, sent a wall of water through the town of Morvi in Gujarat state, killing 1,500 people.
Few cities observe the principle that low lying areas are best preserved as wet lands and drainage channels act as flood cushions, un-encroached upon by humans. In Calcutta (Kolkata) the wetlands issue has centred on the argument that if the city expands into these areas, it would wipe out a major source of fish and related jobs out also exacerbate water logging, a problem which Mumbai and Chennai also face during the monsoon. Invariably, the poor suffer the most as they get pushed into the lowlands.” (see report below)
We must remove large dams like Tehri and cease to remove flood waters from barrages so that normal floods take place every year. Then groundwater will be recharged and more than make up for the loss of irrigation from dams and barrages. Also, sediments will get flushed to the sea and by accepting normal floods we will be saved from devastating floods such as those taking place nowadays.
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