flood,type of flood,flood impact,flood benefits,flood area in India

1. FLOOD
Presented by :-
MAYANK MAHAWAR
M.Sc 4th sem

2. Disaster
• Disaster is a natural or human , caused
phenomenon, which causes serious disruption
of the functioning of a community or a society
causing widespread human, material,economic
and environmental losses which elicited the
ability of the affected community, society to
cope using its resources.
• Floods are a common feature in the country
that occur every year inmany parts including
South India.

3. What is flood..?
Sometimes a water resource
(river, lake or pond) gets flushed with too
much water. Unusually heavy rain sometimes
causes floods. When there is too much water,
it may overflow beyond its normal limits. This
water then spreads over land, flooding it.
Extreme flooding can also be caused by
a tsunami or a large storm that causes a storm
surge.

4. TYPES OF FLOOD
 Flash floods
 River floods
 Coastal Floods
 Urban Flood

5. Flash floods
Flash floods happen in a short time, they have
great volume of water, and are local floods.
The runoff of intense rain results in high flood
waves.
Flash floods result in failure of dams and
more.
It usually happens in desert areas and
mountain regions.

6. River floods
River floods are caused by melting of snow
and precipitation over large areas. They take
place in rivers. Floods in large rivers take hours
to days.
The ground conditions effects the runoff.

7. Coastal Floods
Coastal floods are caused by tides, storms,
tropical cyclones, or tsunamis.
They happen in the ocean and effects the
general public and maritime interests along the
coastline.
They are caused by heavy surf, tidal piling, and
storm surges,
Other factors are tidal cycles, behaviors of the
storm, river or stream runoff, no offshore reefs or
other barriers, and high winds.

8. Urban Floods
Urban floods are when the land is turned from
fields or woods into roads and parking lots.
Since this happens it can’t absorb the rainfall.
During the urban floods all the streets
become rivers and basements become full of
water, they are death traps.
Ice Jam is floating ice that adds up at a man-
made or natural area and stops the flow of
water. This causes the area to flood.

9. Causes of flood
Rains
Each time there are more rains than the drainage
system can take, there can be floods. Sometimes, there
is heavy rain for a very short period that result in
floods. In other times, there may be light rain for many
days and weeks and can also result in floods.
River overflow
Rivers can overflow their banks to cause flooding. This
happens when there is more water upstream than
usual, and as it flows downstream to the adjacent low-
lying areas (also called a floodplain), there is a burst
and water gets into the land.

10. Strong winds in coastal areas
Sea water can be carried by massive winds and
hurricanes onto dry coastal lands and cause
flooding. Sometimes this is made worse if the
winds carry rains themselves. Sometimes water
from the sea resulting from a tsunami can flow
inland to cause damage.
Dam breaking
Dams are man-made blocks mounted to hold
water flowing down from a highland. The power
in the water is used to turn propellers to generate
electricity. Sometimes, too much water held up in
the dam can cause it to break and overflow the
area. Excess water can also be intentionally
released from the dam to prevent it from
breaking and that can also cause floods.

11. Ice and snow-melts
In many cold regions, heavy snow over the winter
usually stays un-melted for sometime. There are also
mountains that have ice on top of them. Sometimes
the ice suddenly melts when the temperature rises,
resulting in massive movement of water into places
that are usually dry. This is usually called a snowmelt
flood

12. FLOOD IMPACT
• Human Loss
• Property Loss
• Affects the Major Roads
• Disruption of Air / Train / Bus services
• Spread of Water-borne CommunicableDiseases
• Communication Breakdown
• Electricity Supply Cut off
• Economic and Social Disruption
• Increase in Air / Water Pollution

13. FLOODS BENEFITS
 Floods (in particular more frequent or smaller floods)
can also bring many benefits, such as
 Recharging ground water,
Making soil more fertile and increasing nutrients in some
soils.
 Flood waters provide much needed water resources in arid
and semi-arid regions where precipitation can be very
unevenly distributed throughout the year.
 Freshwater floods particularly play an important role in
maintaining ecosystems.
 Flooding can spread nutrients to lakes and rivers,
which can lead to increased biomass and
improved fisheries for a few years.

14. Preventing flood
Sea / Coastal Defence Walls Sea walls and tide
gates have been built in some places to prevent tidal
waves from pushing the waters up ashore. In some
areas too, sand bags are made and placed in strategic
areas to retain floodwaters.

15.  Town planning
WATERSUPPLY
FACTORY
POWER HOUSE
UNIVERSITYRESIDENTIALAREA
GOVT.OFFICE
HOSPITAL
NORMALCHANNEL
PARK
FREQUENTFLOOD
FLOODONCE IN 25YEARS
FLOODONCE IN 100YEARS
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II III II I
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16. Retaining walls
In some places, retaining walls levees, lakes,
dams, reservoirs or retention ponds have been
constructed to hold extra water during times
of flooding.

17. Vegetation
Trees, shrubs and grass help protect the land
from erosion by moving water. People in low-
lying areas must be encouraged to use a lot of
vegetation to help break the power of moving
flood water and also help reduce erosion.

18. Education
Education is very important, to inform and
caution people about the dangers of floods,
what causes floods, and what can be done to
minimise its impact.

19. Flood prone zones , Areas in INDIA

20. West Bengal
Orissa
 Andhra Pradesh
 Kerala,
 Assam
 Bihar,
 Gujrat,
Uttar Pradesh
Haryana
Punjab

21. Thank you..