With the arrival of Monsoon, people living in 4 crore hectares area of the country become extremely nervous. No one knows when there will be a flood in the river and their hard earned belongings will be washed away. In comparison to other disasters flood cause more damage to life and property. Twenty percent of deaths caused by floods in the world, occur in India.
What is a flood
The inundation of an area by water is called a flood. In other words, when a river over flows its banks and water spreads in the surrounding areas is a flood.
Various causes of flood, losses by flood and flood control measures are described below.
Cause of flood
The causes of flood in India are as follows –
- (i) Heavy rainfall : Heavy rain in the catchment area of a river causes water to over flow its banks, which results in the flooding of nearby areas.
- (ii) Sediment deposition : River beds become shallow due to sedimentation. The water carrying capacity of such river is reduced. As a result the heavy rain water over flows the river banks.
- (iii) Deforestation : Vegetation hampers the flow of water and forces it to percolate in the ground. As a result of deforestation, the land becomes obstruction free and water flows with greater speed into the rivers and causes flood.
- (iv) Cyclone : Cyclone generated sea-waves of abnormal height spreads the water in the adjoining coastal areas. In October 1994 Orissa cyclone generated severe floods and caused unprecedented loss of life and property.
- (v) Interference in drainage system : Drainage congestion caused by badly planned construction of bridges, roads, railway tracks, canals etc. hampers the flow of water and the result is flood.
- (vi) Change in the course of the river : Meanders and change in the course of the river cause floods.
- (vii) Tsunami : Large coastal areas are flooded by rising sea water, when a tsunami strikes the coast.
Losses by flood
Humans and animals both are affected by flood –
- People are rendered homeless.
- Houses are damaged or collapse.
- Industries are crippled.
- Crops are submerged in flood water.
- Domestic as well as wild animals die.
- Boats and fishing nets etc. are lost or damaged in coastal areas.
- Out break of epidemics like malaria and diarrhoea etc.
- Potable water is contaminated and sometimes becomes scarce.
- Food grains are lost or spoiled, their supplies from outside become difficult.
Losses by annual floods, instead of decreasing are increasing every year. In 1953 2.43 crores of people were affected. By 1987 the number of flood affected people rose to 4.83 crore.
According to an estimate on an-average property worth Rs. 210 crores is lost in floods every year. Flood affects about 6 crore people and crops of one crore hectare are damaged.
Flood prone areas
About 4 crore hectare area of our country is flood-prone, which is one eighth of the total area.
The most flood prone areas are the Brahmaputra, Ganga and Indus basins.
As far as states are concerned, Uttar Pradesh, Bihar, West Bengal and Orissa are the most flood affected states followed by Haryana, Punjab and Andhra Pradesh. Now a days Rajasthan and Gujarat also feel the fury of floods. Karnataka and Maharashtra are no-longer immune to floods.
Flood control measures
- (i) Reservoirs : By constructing reservoirs in the courses of rivers could stores extra water at the time of flood. Such measures adopted till now however, have not been successful. Dams built to control floods of Damodar could not control the flood.
- (ii) Embankments : By building flood protection embankments, floods water can be controlled from overflowing the banks and spreading in near by areas. Building of embankments on Yamuna, near Delhi, has been successful in controlling the flood.
- (iii) Afforestation : The furry of flood could be minimized by planting trees in catchment areas of rivers.
- (iv) Restoration of original drainage system : Drainage system is generally choked by the construction of roads, canals railway tracks etc. Floods could be checked if the original form of drainage system is restored.
About 4 crore hectare area is flood prone. Out of this, 1.44 crore hectare areas has been made secure to some extent from the devastation by floods.
To achieve this goal, embankments and drainage channels have been constructed. Protection of towns and cities have been adopted. Villages are relocated on comparative by higher ground. By the end of Ninth Plan 8000 crore rupees have been spent on flood management.
Some DOs and DON’Ts before, during and after the flood
- (i) Listen to the radio for advance information and advise.
- (ii) Disconnect all electrical appliances, move all valuable household goods and clothing out of reach of flood water. Adopt such measures only when there is a forecast of flood or you suspect that flood water may reach the house.
- (iii) Move vehicles, farm animals and moveable goods to the higher ground.
- (iv) Prevent dangerous pollution.
- (v) Keep all insecticides, pesticides etc. out of the reach of flood water.
- (vi) Switch off electricity and gas, in case you have to leave the house.
- (vii) Lock all door and windows if you have to leave the house.
- (viii) Do not enter flood water on foot or in a vehicle as far as possible.
- (ix) Never wander in the flooded area on your own.
The inundation of an area by rain water is called flood.
Bibliography : NIOS – Geography