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K. Sathish BabuTAM/2013-07Dept. of Agronomy

FLOODS AND ITS MANAGEMENT STRATEGIES

What is a flood?

It is a natural event or occurrence where a piece of land (or area) that

is usually dry land, suddenly gets submerged under water. Some

floods can occur suddenly and recede quickly. Others take days or

even months to build and discharge.

simply, a flood is too much water in the ‘wrong’ place!

What causes flooding?

Rains

River overflow

Strong winds in coastal areas

Dam breaking

Ice and snow-melts

 

Types of floodsRiver floodCoastal floodUrban floodFlash floodIce jam

RIVER FLOODFlooding along rivers is a natural

and inevitable part of life.

Some floods occur seasonally and

some when winter or spring rains,

coupled with melting snows, fill

river basins with too much water,

too quickly.

COASTAL FLOODCoastal floods are

caused by tides, storms, tropical cyclones, or tsunamis.

They happen in the ocean and effects the general public and the coastline.

URBAN FLOODAs land is converted from fields or woodlands to roads and

parking lots, it loses its ability to absorb rainfall.

Urbanization decreases the ability to absorb water 2 to 6 times

over what would occur on natural terrain.

As land is converted from fields or woodlands to roads and

parking lots, it loses its ability to absorb rainfall.

Urbanization decreases the ability to absorb water 2 to 6 times

over what would occur on natural terrain.

FLASH FLOODFlash floods happen in

a short time, they have a great volume of water, and are local floods.

Flash floods result in failure of dams.

They are a threat in steep land, high runoff rates, and narrow streams.

ICE JAM

Floating ice can accumulate at

a natural or man-made

obstruction and stop the flow

of water thereby causing

floods. Flooding too can occur

when there the snow melts at a

very faster rate.

Uttarakhand floods

Kurnool floods

Some of the most notable floods include: The Johnstown Flood of 1889 where over 2200 people lost their lives when the South Fork Dam holding

back Lake Conemaugh broke.

The Huang He (Yellow River) in China floods particularly often. The Great Flood of 1931 caused between

800,000 and 4,000,000 deaths.

The Great Flood of 1993 was one of the most costly floods in United States history.

The North Sea flood of 1953 which killed 2251 people in the Netherlands and eastern England

The 1998 Yangtze River Floods, in China, left 14 million people homeless.

The 2000 Mozambique flood covered much of the country for three weeks, resulting in thousands of

deaths, and leaving the country devastated for years afterward.

The 2005 Mumbai floods which killed 1094 people.

The 2010 Pakistan floods directly affected about 20 million people, mostly by dispolacement, destruction

of crops, infrastructure, property and livelihood, with a death toll of close to 2,000

Effects of flooding

Economic

Environment

People

Beneficial Impacts of Floods

Recharging water sources

Agriculture

Fishery

Management strategiesThere are two different ways to mitigate floods: -o Structuralo Non- Structural

Structural Measures a) Water Shed Management

b) Reservoirs

c) Natural water retention Basins

d) Buildings on elevated area

Non Structural Measures:

Flood mapping

Flood fighting

Flood proofing

Flood Forecasting and warning

Flood insurance

Before flooding occurs

1. Know the route to the nearest safe shelters that you area aware off.

2. Keep the First Aid Kit ready with extra medication for snake bite and

diarrhea

3. Strong ropes for tying things

4. A radio, torch and spare batteries

5. Stocks of fresh water, dry food, candles, matchbox, kerosene etc

6. Umbrellas and bamboo sticks (to protect from snakes)

7. Higher ground where people and animals can take shelter

During Floods

1. Drink boiled water or use halogen tablet to purify water before

drinking.

2. Keep your food covered

3. Do not let children remain on empty stomach

4. Use bleaching powder and lime to disinfect the surroundings

5. Avoid entering flood waters. If you need to enter then were

proper foot wear.

6. Stay away from water over knee level.

After a Flood1. Stay tuned to local radio.

2. Do not allow children to play in, or near, flood waters.

3. Stay away from drains, culverts.

4. Do not use electrical appliances.

5. Do not eat food, which has been in floodwaters.

6. Boil tap water.

7. Use halogen tablets before drinking.

8. Be careful of snake bites, snakebites are common during floods

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