DISASTERS AND THEIR MANAGEMENT
In nature catastrophes such as floods, drought, earth quake, tsunami, happen from time to
time causing immense damage to life and property. It is important to devise means and
methods to manage and minimise from natural disasters as far as possible.
Disasters caused by human activities such as fires, accidents, epidemics are no less sudden
than natural disasters and may be equally devastating. In this lesson you shall learn about
causes, effects, prevention and management of natural as well as human made disaster.
Nature is bountiful full of resources used by the living organisms use for their survival and
well being. But nature has its own control systems. Resources used up are replenished
209
Disasters and their Management
Notes
MODULE - 4
Contemporary
Environmental Issues
excesses are checked, all naturally through the biogeochemical cycles, the food chains and
webs and other natural phenomena. Thus equilibrium is maintained in nature. This is called
ecological balance and has in recent times been disturbed by human activities.
12.2 NATURAL DISASTERS
The Indian sub continent is highly prone to natural disasters. Floods, droughts, cyclones
and earthquakes are recurrent phenomena in India. Susceptibility to disasters is
compounded by frequent occurrences of man-made disasters such as fire. The changing
topography (topo = land) due to environmental degradation also increasing vulnerability to
natural disasters. In 1988, 11.2%of total land area was flood prone, but in 1998 floods
inundated 37% geographical area. Four major disasters that India has experienced in the
recent past are the earthquake in Latur (Maharashtra in 1993), super cyclone in Orissa
(1999), the earthquake in Gujarat (2001) and Tsunami in Tamilnadu and Andhra Pradesh
in December 2004. Frequent disasters lead to enormous loss of life and property. Physical
safety-especially that of the vulnerable groups is routinely threatened by hazards. Natural
disasters can not be prevented but their damaging impact can be reduced through better
forecast, and preparedness to take up effective rescue measures. The four major disasters
mentioned above have very clearly illustrated that we need multi-hazard prevention, response
and recovery plans for natural hazards so that threat to human life and property is minimized.
Disaster risk management is essentially a development problem. Preparedness and planning
for disaster management have to be taken up along with environmental concerns that the
country is facing today.
12.2.1 Type of disasters
There are two types of disasters namely natural disasters and man made disasters. For
example: fire, accidents (road, rail or air), industrial accidents or epidemics are some of
the examples of man-made disasters, both natural and man-made disasters which have
devastating input resulting loss of human life, loss of livelihoods, property and environmental
degradation. Disasters disrupts normal functioning of society and leave long lasting impact.
Earth quake, cyclone, flood and drought are examples of natural disasters.
A. Natural disasters
Certain disasters occur in nature, without human provocation. They are described below.
(a) Floods
Floods are sudden and temporary inundation of a large area as an overflowing of rivers or
reservoirs.
Environmental Science Senior Secondary Course
Notes
210
MODULE - 4
Contemporary
Environmental Issues
Fig. 12.1: Flood
(i) Causes
Floods are caused by rains, high winds, cyclones, tsunami, melting snow or dam burst.
Flood can happen gradually or can happen suddenly due to heavy rains, breach of the
water storage and control structures, spillover. Siltation of the rivers and reservoirs, and
this can enhance the incidence and magnitude of floods.
(ii) Effects
• Casualties
Human and livestock death due to drowning, serious injuries and outbreak of epidemics
like diarrhea, cholera, jaundice or viral infections are common problems faced in flood
affected areas. Even wells, other source of drinking water get submerged resulting in acute
shortage of safe drinking water during floods. Consequently often people are forced to
drink the contaminated floodwater, which may cause serious diseases.
• Structural damage
During floods mud huts and buildings built on weak foundations collapse endangering
human lives and property. Damage may also be cause to roads, rail, dams, monuments,
crops and cattle. Floods may uproot trees and may cause landslides and soil erosion.
• Material loss
Household articles including eatables, electronic goods, beds, clothes, furniture get
submerged in water and get spoilt all materials mounted on ground e.g. food stock,
equipment, vehicles, livestock, machinery, salt pan and fishing boats can be submerged
and spoilt.
• Utilities damage
Utilities such as water supply, sewerage, communication lines, power-lines, transportation
network and railways are put at risk.
• Crop loss
Apart from the loss of human and cattle life, floods cause severe devastation of standing
agricultural crops. Floods water spoils the stored food-grains or harvested crop. Floods
211
Disasters and their Management
Notes
MODULE - 4
Contemporary
Environmental Issues
may affect soil characteristics and may turn them infertile due to the erosion of the top soil
or in coastal areas agricultural lands may turn saline due to flooding by sea water.
• Flood control
Flood control can be achieved through various means. The floodwater can be reduced by
reducing the run-off water through afforestation. Forests promote rainwater percolation in
the ground, thus recharging the groundwater and reducing the run-off water. Construction
of dams also reduces flood water through storage. Dams can store water, which can not
be accommodated in the river downstream may cause floods. Water can be released in a
controlled manner from the dam. Desilting, deepening and increasing embankment increase
the capacity of a river/channel/drain.
(iii) Management
The flood damage can be considerable reduced and loss of human lives can prevented
through proper planning of flood control and management measures.
• Identification of flood prone areas
A rational planning for flood management involves identification the flood prone areas and
frequency and magnitude of flooding in these areas.
• Flood forecasting
Normally there is a reasonable timely warning by alerting people and moving them to safer
area well in time. Measurement of intensity of rainfall in the catchment area provide sufficient
clue to hydrology engineers to calculate the possible submergence area along a river well
before the flooding occurs. Accordingly expected run-off volume people can be warned
to evacuate the likely areas to be flooded and advise to go to safer places along with their
belongings including livestock. In India has a large network of rain measuring stations,
flood warnings are issued by the Central Water Commission (CWC), Irrigation and Flood
Control Department and Water Resources Department.
• Land use planning
Land use planning is very important for all the developmental activities. No major
development should be permitted in flood prone areas. If construction is unavoidable it
should be able to withstand the flood forces. Buildings should be constructed on elevated
areas.
Afforestation should be encouraged. Deforestation in the catchments areas should be
discouraged because deforestation results in excessive run off water and causes soil erosion,
which is the main cause of river siltation resulting in floods. Any construction, which causes
obstruction in drainage flow, should not be permitted. Encroachment of the storm water
drains should not be allowed.
Environmental Science Senior Secondary Course
Notes
212
MODULE - 4
Contemporary
Environmental Issues
This reduces the risk of floods. Some precautionary measures are as follows -
• Build houses away from flood prone area.
• Keep yourself alert and updated to weather and flood forecasting information.
• In case evacuation warnings are issued, immediately go to the shelters provided.
• When you are moving to a shelter, move your valuable articles to safer elevated places
so that they are not destroyed by flood water.
• Store extra food, such as rice, pulses etc. for emergency.
• Do not touch any loose electric wire to avoid electrocution.
• Do not spread rumours or listen to them.
• Make provision for adults and children who need special diet.
• After the flood is over, get yourself and your family members inoculated against diseases
and seek medical care for injured and sick.
• Clear the house and dwellings of debris.
• Report any loss to the revenue authorities.
(b) Drought
Drought is an event that results from lower than normal expected rainfall over a season or
period. The low rainfall is insufficient to meet the needs of human beings, plants, animals
and agriculture. Short fall in rain results in drying of rivers, lakes, reservoirs and drying of
wells due to excessive withdrawal and poor recharge of ground water and loss of crop
yield due to shortage of water are some of the main indicators of drought.
(i) Causes
Drought occurs due to shortage of rainfall. As per Meteorological Department if rainfall is
deficient by more than 10% of the annual average rainfall, the condition is said to be that of
drought. The severity of drought is determined by the extent of deviation of rainfall from
the average. In the recent past frequency of periods of drought have increasing due to
deforestation and environmental degradation.
(ii) Effects
Drought has severe effects on agriculture. To start with drought affects mostly rainfed
crops and subsequently the irrigated crops. The herdsman, landless labours, subsistence
farmers, women, children and farm animals are most affected.
• Crop failure or food shortage leading to large scale starvation and death.
• Affects dairy activities, timber and fisheries.
• Increases unemployment.
MPPSC MAINS PREPARATION GS DISASTER MANAGMENTMPPSC MAINS PREPARATION GS DISASTER MANAGMENTMPPSC MAINS PREPARATION GS DISASTER MANAGMENTMPPSC MAINS PREPARATION GS DISASTER MANAGMENTMPPSC MAINS PREPARATION GS DISASTER MANAGMENTMPPSC MAINS PREPARATION GS DISASTER MANAGMENTMPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT V V V MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT V MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT V MPPSC MAINS PREPARATION GS DISASTER MANAGMENT V MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT
In nature catastrophes such as floods, drought, earth quake, tsunami, happen from time to
time causing immense damage to life and property. It is important to devise means and
methods to manage and minimise from natural disasters as far as possible.
Disasters caused by human activities such as fires, accidents, epidemics are no less sudden
than natural disasters and may be equally devastating. In this lesson you shall learn about
causes, effects, prevention and management of natural as well as human made disaster.
Nature is bountiful full of resources used by the living organisms use for their survival and
well being. But nature has its own control systems. Resources used up are replenished
209
Disasters and their Management
Notes
MODULE - 4
Contemporary
Environmental Issues
excesses are checked, all naturally through the biogeochemical cycles, the food chains and
webs and other natural phenomena. Thus equilibrium is maintained in nature. This is called
ecological balance and has in recent times been disturbed by human activities.
12.2 NATURAL DISASTERS
The Indian sub continent is highly prone to natural disasters. Floods, droughts, cyclones
and earthquakes are recurrent phenomena in India. Susceptibility to disasters is
compounded by frequent occurrences of man-made disasters such as fire. The changing
topography (topo = land) due to environmental degradation also increasing vulnerability to
natural disasters. In 1988, 11.2%of total land area was flood prone, but in 1998 floods
inundated 37% geographical area. Four major disasters that India has experienced in the
recent past are the earthquake in Latur (Maharashtra in 1993), super cyclone in Orissa
(1999), the earthquake in Gujarat (2001) and Tsunami in Tamilnadu and Andhra Pradesh
in December 2004. Frequent disasters lead to enormous loss of life and property. Physical
safety-especially that of the vulnerable groups is routinely threatened by hazards. Natural
disasters can not be prevented but their damaging impact can be reduced through better
forecast, and preparedness to take up effective rescue measures. The four major disasters
mentioned above have very clearly illustrated that we need multi-hazard prevention, response
and recovery plans for natural hazards so that threat to human life and property is minimized.
Disaster risk management is essentially a development problem. Preparedness and planning
for disaster management have to be taken up along with environmental concerns that the
country is facing today.
12.2.1 Type of disasters
There are two types of disasters namely natural disasters and man made disasters. For
example: fire, accidents (road, rail or air), industrial accidents or epidemics are some of
the examples of man-made disasters, both natural and man-made disasters which have
devastating input resulting loss of human life, loss of livelihoods, property and environmental
degradation. Disasters disrupts normal functioning of society and leave long lasting impact.
Earth quake, cyclone, flood and drought are examples of natural disasters.
A. Natural disasters
Certain disasters occur in nature, without human provocation. They are described below.
(a) Floods
Floods are sudden and temporary inundation of a large area as an overflowing of rivers or
reservoirs.
Environmental Science Senior Secondary Course
Notes
210
MODULE - 4
Contemporary
Environmental Issues
Fig. 12.1: Flood
(i) Causes
Floods are caused by rains, high winds, cyclones, tsunami, melting snow or dam burst.
Flood can happen gradually or can happen suddenly due to heavy rains, breach of the
water storage and control structures, spillover. Siltation of the rivers and reservoirs, and
this can enhance the incidence and magnitude of floods.
(ii) Effects
• Casualties
Human and livestock death due to drowning, serious injuries and outbreak of epidemics
like diarrhea, cholera, jaundice or viral infections are common problems faced in flood
affected areas. Even wells, other source of drinking water get submerged resulting in acute
shortage of safe drinking water during floods. Consequently often people are forced to
drink the contaminated floodwater, which may cause serious diseases.
• Structural damage
During floods mud huts and buildings built on weak foundations collapse endangering
human lives and property. Damage may also be cause to roads, rail, dams, monuments,
crops and cattle. Floods may uproot trees and may cause landslides and soil erosion.
• Material loss
Household articles including eatables, electronic goods, beds, clothes, furniture get
submerged in water and get spoilt all materials mounted on ground e.g. food stock,
equipment, vehicles, livestock, machinery, salt pan and fishing boats can be submerged
and spoilt.
• Utilities damage
Utilities such as water supply, sewerage, communication lines, power-lines, transportation
network and railways are put at risk.
• Crop loss
Apart from the loss of human and cattle life, floods cause severe devastation of standing
agricultural crops. Floods water spoils the stored food-grains or harvested crop. Floods
211
Disasters and their Management
Notes
MODULE - 4
Contemporary
Environmental Issues
may affect soil characteristics and may turn them infertile due to the erosion of the top soil
or in coastal areas agricultural lands may turn saline due to flooding by sea water.
• Flood control
Flood control can be achieved through various means. The floodwater can be reduced by
reducing the run-off water through afforestation. Forests promote rainwater percolation in
the ground, thus recharging the groundwater and reducing the run-off water. Construction
of dams also reduces flood water through storage. Dams can store water, which can not
be accommodated in the river downstream may cause floods. Water can be released in a
controlled manner from the dam. Desilting, deepening and increasing embankment increase
the capacity of a river/channel/drain.
(iii) Management
The flood damage can be considerable reduced and loss of human lives can prevented
through proper planning of flood control and management measures.
• Identification of flood prone areas
A rational planning for flood management involves identification the flood prone areas and
frequency and magnitude of flooding in these areas.
• Flood forecasting
Normally there is a reasonable timely warning by alerting people and moving them to safer
area well in time. Measurement of intensity of rainfall in the catchment area provide sufficient
clue to hydrology engineers to calculate the possible submergence area along a river well
before the flooding occurs. Accordingly expected run-off volume people can be warned
to evacuate the likely areas to be flooded and advise to go to safer places along with their
belongings including livestock. In India has a large network of rain measuring stations,
flood warnings are issued by the Central Water Commission (CWC), Irrigation and Flood
Control Department and Water Resources Department.
• Land use planning
Land use planning is very important for all the developmental activities. No major
development should be permitted in flood prone areas. If construction is unavoidable it
should be able to withstand the flood forces. Buildings should be constructed on elevated
areas.
Afforestation should be encouraged. Deforestation in the catchments areas should be
discouraged because deforestation results in excessive run off water and causes soil erosion,
which is the main cause of river siltation resulting in floods. Any construction, which causes
obstruction in drainage flow, should not be permitted. Encroachment of the storm water
drains should not be allowed.
Environmental Science Senior Secondary Course
Notes
212
MODULE - 4
Contemporary
Environmental Issues
This reduces the risk of floods. Some precautionary measures are as follows -
• Build houses away from flood prone area.
• Keep yourself alert and updated to weather and flood forecasting information.
• In case evacuation warnings are issued, immediately go to the shelters provided.
• When you are moving to a shelter, move your valuable articles to safer elevated places
so that they are not destroyed by flood water.
• Store extra food, such as rice, pulses etc. for emergency.
• Do not touch any loose electric wire to avoid electrocution.
• Do not spread rumours or listen to them.
• Make provision for adults and children who need special diet.
• After the flood is over, get yourself and your family members inoculated against diseases
and seek medical care for injured and sick.
• Clear the house and dwellings of debris.
• Report any loss to the revenue authorities.
(b) Drought
Drought is an event that results from lower than normal expected rainfall over a season or
period. The low rainfall is insufficient to meet the needs of human beings, plants, animals
and agriculture. Short fall in rain results in drying of rivers, lakes, reservoirs and drying of
wells due to excessive withdrawal and poor recharge of ground water and loss of crop
yield due to shortage of water are some of the main indicators of drought.
(i) Causes
Drought occurs due to shortage of rainfall. As per Meteorological Department if rainfall is
deficient by more than 10% of the annual average rainfall, the condition is said to be that of
drought. The severity of drought is determined by the extent of deviation of rainfall from
the average. In the recent past frequency of periods of drought have increasing due to
deforestation and environmental degradation.
(ii) Effects
Drought has severe effects on agriculture. To start with drought affects mostly rainfed
crops and subsequently the irrigated crops. The herdsman, landless labours, subsistence
farmers, women, children and farm animals are most affected.
• Crop failure or food shortage leading to large scale starvation and death.
• Affects dairy activities, timber and fisheries.
• Increases unemployment.
MPPSC MAINS PREPARATION GS DISASTER MANAGMENTMPPSC MAINS PREPARATION GS DISASTER MANAGMENTMPPSC MAINS PREPARATION GS DISASTER MANAGMENTMPPSC MAINS PREPARATION GS DISASTER MANAGMENTMPPSC MAINS PREPARATION GS DISASTER MANAGMENTMPPSC MAINS PREPARATION GS DISASTER MANAGMENTMPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT V V V MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT V MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT V MPPSC MAINS PREPARATION GS DISASTER MANAGMENT V MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT MPPSC MAINS PREPARATION GS DISASTER MANAGMENT