The document discusses the causes and impacts of flooding. Flooding occurs when there is too much rainwater for rivers and basins to contain, often caused by heavy rainfall, overflowing rivers, or damaged infrastructure. Flooding can disrupt transportation, damage property and possessions, and destroy crops and farmland. It also poses major health risks through contaminated water and increased disease vectors, with impacts like stress, illness, and toxic exposure for humans. Proper precautions and flood prevention measures aim to protect people and minimize these risks.

1. SL NO. PARTICULARS
1 INTRODUCTION
2 WHAT IS A FLOOD
3 TYPES OF FLOODING
4 FLOOD IMPACTS
5 SOURCES OF HEALTH-
6 RISKS DUE TO FLOOD
7 IMPORTANT IMPACT OF
8 FLOOD ON HUMANHEALTH
BUT WHAT CAUSES A FLOOD
9 CONCLUSION
10 REFERENCES

2. Man’s activities along with his over-indulgence in the environmental
interaction have disturbed the ecological equilibrium. The consequent active forces
within the earth and environment, are the cause of environmental hazards like
earthquakes, droughts, and floods. Such disasters leads to destructions, and likely
damages both lives and property. The ecosystem imbalance arises when physical
growth and development trails fast with rapid urbanization. It leads to the construction
of large scale water impoundments, destruction of forest areas, development of
industries with ill-management of waste drains, and paving of major highways.

3.  WHAT IS A FLOOD?
 A flood is a natural event that can have far reaching effects on people and the
environment. Put simply, a flood is too much water in the ‘wrong’ place!
 WHAT CAUSES FLOODS?
 A flood is caused by a combination of heavy rainfall causing river / oceans to over
flow their banks, and can happen at any time of the year, not just in the winter.
Floods generally develop over a period of days, when there is too much rainwater
to fit in the rivers and water spreads over the land next to it (the ‘floodplain’).
However, they can happen very quickly when lots of heavy rain falls over a short
period of time.

4. These ‘flash floods’ occur with little or no warning and cause the biggest
loss of human life than any other type of flooding. Coastal areas are also at risk from
sea flooding, when storms and big waves bring seawater onto the land. The worst
cases of flooding may occur if there is a combination of storms, ‘spring tides’ and low
atmospheric pressure.

5.  WHAT ARE THE EFFECTS OF FLOODING?
 Flooding can be very dangerous – only 15cms of fast-flowing water are needed to
knock you off your feet! Floodwater can seriously disrupt public and personal
transport by cutting off roads and railway lines, as well as communication links
when telephone lines are damaged. Floods disrupt normal drainage systems in
cities, and sewage spills are common, which represents a serious health hazard,
along with standing water and wet materials in the home.
 Bacteria, mould and viruses, cause disease, trigger allergic reactions, and continue
to damage materials long after a flood.

6.  Floodwater can severely disrupt public and personal transport by cutting off roads
and railway lines, as well as communication links when telephone lines are
damaged. Unfortunately, flooding not only disrupts many people’s lives each year,
but it frequently creates personal tragedies when people are swept away and
drowned.

7. WHAT’S BEING DONE TO PREVENT FLOODING?
The Environment Agency aims to protect people and their property from flooding,
helping
organisations like the police to give warnings of possible floods so that people can
make arrangements or move out of the area if it is dangerous. We do this by issuing one
of the following flood codes:
Flooding expected. Affecting homes, businesses and main roads.
Severe Flooding Expected. Imminent danger to life and property.
Flood water levels receding. Check all is safe to return. Seek Advice.

8. TYPES OF FLOODING
The flood types are explained below.
Riverine floods:
Some rivers are prone to frequent floods – annually or seasonally, while others may
not be affected. Riverine floods can be further classified by the rapidity of flooding or
its magnitude.
In the first classification, a flood can either be a flash flood or a normal flood.
High stage flows
This is technically not a flood as the flow is still confined between the banks. Still the
water may be deep and the velocities high so that normal river uses are disrupted.
Bathing, boating, fishing etc. can either be impossible or extremely risky.

9. Minor floods
Such a flood may affect only a small part of the riparian community. It usually
inundates the low lying areas such as paddy fields, meadows etc. Economic loss is
small and number of evacuations is also limited. Communications are rarely severed.
Major Floods
A flood that affects a significant part of the riparian community and causes higher
economic damage is considered a major flood. Residential and business areas as well
as public buildings may go under water.
Dangerous / critical floods
This term denotes flooding that inundates a large area of the basins and requires
evacuation of most of the riparian population. The transport gets cut off and normal
services are disrupted. A dangerous flood covers an extensive area of the flood plain
and may remain stagnant for several days.

10.  Urban floods / Drainage congestion
 In many cases the so called floods are not caused by rivers overflowing but are
caused by the inadequate drainage facilities. In urban areas this phenomenon occurs
due to haphazard construction with poor planning which does not allow sufficient
retention and percolation areas.

11. Floods caused by spilling of Reservoirs
When reservoirs spill, it may cause flooding downstream. The spilling may be natural
or it may be caused by the reservoir operator opening the gates
Dam Breach
Most destructive floods are caused by the breaching of the dam of a reservoir. This
will release large volumes of water stored in the reservoir.
FLOOD IMPACTS
Damage to houses and property and important possessions such as furniture,
electrical appliances, etc.,
Livelihood of people because floods destroy crops, farmlands and livestock.
Food shortage.

12.  SOURCES OF HEALTH-RISKS DUE TO FLOOD
 Usually, the general attention is paid towards the risk of physical property
destruction caused by floods. At the same time, it is very important to follow some
basic practices and precautions to prevent possible diseases and injuries suffered
during and after flooding. Also, it is important to know about the sources of health
risks caused due to flood.
 IMPORTANT IMPACT OF FLOOD ON HUMAN HEALTH
 The contaminated sources of flood water, and the vectors and pathogens developed
due to the flood, causes many vectorborne diseases, stress, toxic effects as some of
harmful impact on human health.

13.  BUT WHAT CAUSES A FLOOD?
 Floods can either be natural or as a result of human activity and infrastructure.
The most common causes of flooding are:
 Heavy Rains
 Rivers that Overflow
 Dams that are Damaged
 Urban Drainage Systems
 Storm Surges and Tsunamis
 Channels with Steep Sides
 Lack of Vegetation

14. CONCLUSION
Floods, one of the most worst natural disasters not only make the victims
homeless and financially disabled, but also cause mental stress, diseases and
shattered life. It is difficult for the depressed flood victims to ever identify where
to start while avoiding potential health risks and hazardous effects of devastating
floods. The threats to one’s health and safety during and after the flood are
unimaginable. In the flood that occurred in Bangladesh in 1988, diarrhea spread as
the most common illness and a major causes of many a deaths.
REFERENCES
[1] Boulder country (2002). Flood protection handbook, Boulder, Colorado.
[2] Center for Disease Control and Prevention (2004). Key facts about Flood
Recovery. Facts Sheet 10 September 2004. Atlanta. CDC.