FLOOD CONTROL

Submitted byTHARA .R

INTRODUCTIONFlood have been an integral part of human

experience.Due to river bank settlement in Asia and Africa.Loss valuable top soil and nutrients.A flood is defined as “over flow of inland and

tidal waters causing rapid and usual accumulation or run off of surface water. From any source or a mudflow in a considerable area of land”

Flood is a natural phenomenon associated with hydrological cycle and not an accumulation of large quantities

Floods are caused under the influence of both natural and anthropogenic factors which vary from place to place.

Long part of the earth is submerged under the water for several days.

Flood is very common in UP, Bihar, west Bengal.Due to intensic monsoon, flood causing common

rivers of India are Ganga, Yamuna etc.The word ‘flood’ comes from the old English flood Word common to Germanic languages.

CAUSES OF FLOODSThe main causes of flood can be grouped in to two

types.1. Natural causes

The important natural causes of floods are :-Prolonged rainfallHigh intensity rain fallMeandering passage of riversLand sliders and volcanic eruptionsBlockage of river passageHigh tides, storm surge or tsunamic coastal area 

Man- made causes

The important man made causes are:-1. Construction work2. Urbanisation3. Alteration of river passage4. Construction of clam, bridges and storage

bodies5. Deforestation and6. Farming

Human activity in the coastal low lands and the river valleys can intensity the hazard of flooding such activities include:-

i. Drained declaimed wetland for agricultureii. Removal of sand from beachiii. Ground water extraction and mining of gas

and oiliv. Destroying natural vegetation in muddy coast

linesv. Destroying or damage of coral reels and vi. Deforestation and soil erosion

EFFECTS Primary effects

Physical damage :- damage to structures, including bridges, buildings, sewerage systems.

Secondary effects

Water supplies :- contamination of water clean drinking water will become scarce

Diseases :- unhygienic conditions spread of water become diseases

Crops and food supplies :- shortage of food crop can be caused due to loss of entire harvest

Trees :- non tolerant species can die from suffocation Transport :- transport links destroyed. So hard to get

emergency aid to those who need it.

Tertiary and long term effects

Economic :- economic hardship due to temporary decline in tourism, rebuilding costs, food shortage leading to price increase etc

Psychological :- flooding can be highly traumatic for individuals, in particular where deaths, serious injuries and loss of property occurs.

MANAGEMENT OF FLOODS Following are some control methods to prevent

flood.

1. Delay in reaching of the surface run off water to the river.

Forests prevent flood in several waysI Forest increase infiltration of rain water and

there by decrease the quantity of surface run off water.

II Forests prevent soil erosion thus prevent silting of the river and other water bodies.

III The reduction of silting and sedimentation in the river increases. Water holding capacity of rivers and move water is adjusted and regulated.

Management of rapid discharge of river water :-

Rapid flow of water can be facilitated by reducing meandering of the river.

Reduction of water volume of the river

Volume of water in the river an be regulated by constructing flood control storage reservoirs, such as dams.

Minimization of flood effects By constructing levees and embankment

using stones, rock pieces, cement, concrete etc.

It is possible to prevent outflow of water during rains.

CONTROLIn many countries across the world rivers,

prone to flood are often carefully managedDefenses such as levees, bunds and

reservoirs, are used to prevent rivers from bursting their banks.

CONCLUSION

Flood is the natural disaster It affect the all environment including plants

and animals (living & non living)Preventing methods.