In the past people constructed protective bunds or drainage channels for the protection of their houses and even cultivated lands from floods. They were, however, constructed only when there was immediate danger of flood.
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The embankments were not strengthened until people were threatened by another flood. Thus, they were constructed in a haphazard way. Since 1954, concerted efforts on scientific lines have been made at government level to control floods. Multi-purpose projects have provided protection from floods to some areas.
The dams across the Satluj, the Mahanadi, the Godavari and the Damodar have reduced the intensity and the frequency of floods along these rivers to some extent. Though multipurpose projects have gone a long way in reducing the intensity of floods, they do not seem to have completely solved the problem. In West Bengal a large area west of the Hooghly was flooded in 1956 and 1959 soon after the completion of the D.V.C. Project.
Similarly coastal districts of Odisha were devastated by unprecedented high floods in 1960 after the completion of Hirakud Dam. The Brahmani, the Baitarani and the Sulandi flow close to one another and form a common delta contiguous to the northern part of the Mahanadi Delta. Torrential rainfall in the catchment areas of all these streams flooded their deltaic courses simultaneously.
In addition to the storage dams across big rivers, the following flood control measures are adopted in some parts of our country:
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(1) Drainage channels are dug in the areas which suffer from poor drainage and water logging. Some of them are well-maintained and connected ultimately with the rivers. It is advisable to keep the drainage channels away from those towns which are situated at a lower level.
A large section of Rohtak (Haryana), situated in a saucer-shaped depression suffered from a disastrous flood in 1960 because drainage channel which flow nearby and at relatively a high-level overflowed its banks. Nearly three-fourths of the population left the town to safe places and its important sections remained under water for nearly two months.
(2) Where roads and railways run across the direction of the flow of flood water, adequate number of culverts should be provided. Canals also offer obstruction; they should flow in aqueducts in flood- affected areas.
(3) The catchment areas of the rivers should be afforested. Indiscriminate cutting of trees should be prohibited. The Shivalik Range and the Chhota Nagpur Plateau require immediate afforestation.
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(4) Desilting of those reaches of the river courses and drainage channels which obstruct the free flow of flood water should be resorted to. Straightening of the meandering river channels increases gradient and thus permits free flow of water.
(5) Storage dams should be built across those small streams which have devastated large areas in the past.
(6) The high embankments constructed along the river courses have saved some areas. For example, nearly 120 kms. Long embankment on each side of the Kosi in Nepal and Bihar was built in the recent past as a measure against floods. These embankments are 5 to 16 kms. Apart. The vagaries of the Kosi have been thus confined within embankments and as many as 20,720 square kms. Of land has been saved from devastation. Embankments along the Ghaghara, the Rapti, the Burhi Gandak and a number of other small and large rivers are under construction.
(7) Villages built on the raised ground could also minimize misries of people. The fields may be flooded by surging water, but houses built on raised ground may keep food-grains, fodder, life and property safe from devastation.
In the alluvial plains, it is not possible to eliminate completely the danger of floods. Even if it is done at a huge cost, benefit of fertile silt will be lost and the deposition of silt in the river channels would pose constant danger of erosion to the dykes.