DISASTER MANAGEMENT MATERIAL

4. Discuss the disaster management in environment.
Geological processes like earthquakes, volcanoes, floods and landslides are normal natural events which have resulted in the formation of the earth that we have today. They are, however, disastrous in their impacts when they affect human settlements. Human societies have witnessed a large number of such natural hazards in different parts of the world and have tried to learn to control these processes, to some extent.

Earthquakes: Earthquakes occur due to sudden movements of earth.s crust. The earth.s crust has several tectonic plates of solid rock which slowly move along their boundaries. When friction prevents these plates from slipping, stress builds up and results in sudden fractures which can occur along the boundaries of the plates or fault lines (planes of weakness) within the plates. This causes earthquakes, the violent, short-term vibrations in the earth. The point on a fault at which the first movement occurs during an earthquake is called the epicenter.

The severity of an earthquake is generally measured by its magnitude on Richter Scale, as shown below:








The largest earthquake ever recorded occurred on May 22, 1960 in Chile with the estimated magnitude of 9.5 on Richter Scale, affecting 90,000 square miles and killing 6,000 people. The devastating earthquake which hit Bhuj Town in Gujarat had caused massive damage, killing 20,000-30,000 people and leaving many injured. It had an energy equivalent to a 5.3 megaton hydrogen bomb.

Earthquake-generated water waves called tsunamis can severely affect coastal areas. These giant sea swells can move at a speed upto 1000 Km/hr or even faster. While approaching the sea shore they may often reach 15 m or sometimes upto 65 m in height and cause massive devastation in coastal areas. In China such waves killed 8,30,000 people in 1556 and 50,000 in 1976. Anthropogenic activities can also cause or enhance the frequency of earthquakes. Three such activities identified are:

(a) Impoundment of huge quantities of water in the lake behind a big dam.
(b) Under ground nuclear testing.
(c) Deep well disposal of liquid waste.

Damage to property and life can be prevented by constructing earthquake-resistant buildings in the earthquake prone zones or seismic areas. For this, the structures are heavily reinforced, weak spots are strategically placed in the building that can absorb vibrations from the rest of the building, pads or floats are placed beneath the building
on which it can shift harmlessly during ground motion. Wooden houses are preferred in earthquake prone areas as in Japan.


Floods

Generally the stream channels accommodate some maximum stream flow. However, due to heavy rains or sudden snow melt the quantity of water in streams exceeds their capacity and water overflows the banks and causes inundation of the surrounding land. This situation is called flood.
A flood generally doesn.t damage property or cause casualities to an extent as done by other natural disasters. However, it causes a great economic loss and health related problems due to widespread contamination. Virtually anything the flood water touches gets contaminated, posing serious threat to health due to outbreak of epidemics.

Human activities have been the main causes for increasing the severity and frequency of floods. Construction of roads, parking space and buildings that cover the earths surface hardly allows infiltration of water into the soil and speeds up the runoff. Clearing of forests for agriculture has also increased the severity of floods. In India, Uttar Pradesh is considered to be amongst the worst flood hit states of the country. It has nearly 20% of the total 40 million hectares of flood prone zone of the country.

Flood plains, the low lying areas which get inundated during floods help to reduce floods. Building up of flood control structures like flood walls or deepening of river channels have only transferred the problems downstream. Building walls prevents spilling out the flood water over flood plains, but it increases the velocity of water to affect the areas downstream with greater force. Table 5.4 shows the occurrence of natural hazards in our country.

On an average, every year one major disaster hits India, causing huge economic losses and loss of human life. There is a need for systematic studies and strategies to evolve a Disaster Management Plan for our country.

To check the floods, efforts need to be made to restore wetlands, replace ground cover on water-courses, build check-dams on small streams, move buildings off the flood plains etc. Instead of raising buildings on flood plains, it is suggested that floodplains should be used for wildlife habitat, parks, recreational areas and other uses, which are not susceptible to flood damage. River-networking in the country is also being proposed to deal with the flood problem.

Landslides
Landslide occurs when coherent rock of soil masses move downslope due to gravitational pull. Slow landslips don.t cause much worry but sudden rockslides and mudslides are dangerous. Water and vegetation influence landslides. Chemical action of water gradually cause chemical weathering of rocks making them prone to landslides. Vegetation consolidates the slope material, provides cohesion by its root system and also retards the flow of water and its erosion capacity.

However, this can be masked by many other exerting factors like:
(i) Earthquakes, vibrations etc.
(ii) Disturbances in resistant rock overlying rock of low resistance. (iii) Saturation of the unconsolidated sediments with water.
(iv) Unconsolidated sediments exposed due to logging, road or house building.
Landslides are governed by the forces which tend to pull the earth material down slope (move in case of slopes with steeper slip plane) and resisting forces which tend to resist such movements.

It is difficult to control landslides. However, these can be minimized by stabilizing the slope by:
(i) Draining the surface and subsurface water.
(ii) Providing slope support like gabions (wired stone blocks)
(iii) Concrete support at the base of a slope.

Cyclones

Cyclones are recurring phenomena in the tropical coastal regions. Tropical cyclones in the warm oceans are formed because of heat and moisture. One of the requirements for formation of tropical cyclones is that the sea surface temperature (SST) should be above 26°C.

Tropical cyclones move like a spinning top at the speed of 10-30 Km per hour. They can last for a week or so and have a diameter varying between 100 to 1500 Km. Since in the western parts of the main ocean no cold currents exist, tropical cyclones originate there.

Tropical cyclones are called hurricanes in the Atlantic, Caribbean and north eastern Pacific,. ‘typhoons’ in the western Pacific; and ‘cyclones’ in the Indian Ocean and ‘willy willies’ in the sea around Australia. More storms occur in the Bay of Bengal than in the Arabian Sea. Of 5-6 storms that form in the year about half of them are severe.

Hurricane winds (74 miles per hour or more), rains and storm surge (often 50-100 miles wide dome of water) often devastate the area where it strikes on land. The devastation is more when storm surge and normal astronomical tide coincide. Sea water with combined force rushes inlands and inundates the low lying areas.

Management: It is difficult to stop the recurrence of cyclones. Some long term defence measures can help to protect us from devastation. Such measures include, planting more trees on the coastal belt, construction of dams, dykes, embankments, storm shelter, wind breaks, proper drainage and wide roads for quick evacuation.

Explain the solid waste management.
Higher standards of living of ever increasing population has resulted in
an increase in the quantity and variety of waste generated. It is now
realized that if waste generation continues indiscriminately then very
soon it would be beyond rectification. Management of solid waste has,
therefore, become very important in order to minimize the adverse
effects of solid wastes. Solid waste (waste other than liquid or gaseous)
can be classified as municipal, industrial, agricultural, medical, mining
waste and sewage sludge.
Sources of Urban and Industrial Wastes
Urban waste consists of medical waste from hospitals; municipal solid
wastes from homes, offices, markets (commercial waste) small cottage
units, and horticulture waste from parks, gardens, orchards etc.
l Waste from homes (Domestic waste) contains a variety of
discarded materials like polyethylene bags, empty metal and
aluminium cans, scrap metals, glass bottles, waste paper,
diapers, cloth/rags, food waste etc.
l Waste from shops mainly consists of waste paper, packaging
material, cans, bottles, polyethylene bags, peanut shells,
eggshells, tea leaves etc.
l Biomedical waste includes anatomical wastes, pathological
wastes, infectious wastes etc.
l Construction/demolition waste includes debris and rubbles,
wood, concrete etc.
l Horticulture waste and waste from slaughter houses include
vegetable parts, residues and remains of slaughtered animals,
respectively.
The urban solid waste materials that can be degraded by microorganisms
are called biodegradable wastes. Examples of this type of
waste are vegetable wastes, stale food, tea leaves, egg shells, peanut
shells, dry leaves etc. Wastes that cannot be degraded by microorganisms
are called non-biodegradable wastes. For example,
polyethylene bags, scrap metal, glass bottles etc.
Industrial waste: Industrial waste consists of a large number
of materials including factory rubbish, packaging material,
organic wastes, acids, alkalis and metals etc. During some
industrial processing large quantities of hazardous and toxic
materials are also produced. The main sources of industrial
wastes are chemical industries, metal and mineral processing
industries. Radioactive wastes are generated by nuclear power
plants. Thermal power plants produce fly ash in large
quantities. Solid wastes from other types of industries include
scrap metal, rubber, plastic, paper, glass, wood, oils, paints,
asphalt, tars, dyes, scrap leather, ceramics, abrasives, slag,
heavy metals, asbestos, batteries. In Europe and North
America the environmental laws and safety laws are becoming
more stringent due to which disposal of hazardous wastes is
becoming a problem. Cost of disposal of such wastes is
increasing. Therefore, these wastes are being exported to
developing countries which do not even have sufficient
knowledge or technique for their disposal.
Effects of Solid Wastes
Municipal solid wastes heap up on the roads due to improper disposal
system. People clean their own houses and litter their immediate
surroundings which affects the community including themselves. This
type of dumping allows biodegradable materials to decompose under
uncontrolled and unhygienic conditions. This produces foul smell and
breeds various types of insects and infectious organisms besides spoiling
the aesthetics of the site.
Industrial solid wastes are sources of toxic metals and hazardous
wastes, which may spread on land and can cause changes in physico-
chemical and biological characteristics thereby affecting productivity
of soils. Toxic substances may leach or percolate to contaminate the
ground water.
In refuse mixing the hazardous wastes are mixed with garbage
and other combustible waste. This makes segregation and disposal all
the more difficult and risky. Various types of wastes like cans, pesticides,
cleaning solvents, batteries (zinc, lead or mercury) radioactive materials,
plastics are mixed up with paper, scraps and other non-toxic materials
which could be recycled. Burning of some of these materials produce
dioxins, furans and polychlorinated biphenyls, which have the potential
to cause various types of ailments including cancer.
Industrial waste: Industrial waste consists of a large number
of materials including factory rubbish, packaging material,
organic wastes, acids, alkalis and metals etc. During some
industrial processing large quantities of hazardous and toxic
materials are also produced. The main sources of industrial
wastes are chemical industries, metal and mineral processing
industries. Radioactive wastes are generated by nuclear power
plants. Thermal power plants produce fly ash in large
quantities. Solid wastes from other types of industries include
scrap metal, rubber, plastic, paper, glass, wood, oils, paints,
asphalt, tars, dyes, scrap leather, ceramics, abrasives, slag,
heavy metals, asbestos, batteries. In Europe and North
America the environmental laws and safety laws are becoming
more stringent due to which disposal of hazardous wastes is
becoming a problem. Cost of disposal of such wastes is
increasing. Therefore, these wastes are being exported to
developing countries which do not even have sufficient
knowledge or technique for their disposal.
Effects of Solid Wastes
Municipal solid wastes heap up on the roads due to improper disposal
system. People clean their own houses and litter their immediate
surroundings which affects the community including themselves. This
type of dumping allows biodegradable materials to decompose under
uncontrolled and unhygienic conditions. This produces foul smell and
breeds various types of insects and infectious organisms besides spoiling
the aesthetics of the site.
Industrial solid wastes are sources of toxic metals and hazardous
wastes, which may spread on land and can cause changes in physico-
chemical and biological characteristics thereby affecting productivity
of soils. Toxic substances may leach or percolate to contaminate the
ground water.
In refuse mixing the hazardous wastes are mixed with garbage
and other combustible waste. This makes segregation and disposal all
the more difficult and risky. Various types of wastes like cans, pesticides,
cleaning solvents, batteries (zinc, lead or mercury) radioactive materials,
plastics are mixed up with paper, scraps and other non-toxic materials
which could be recycled. Burning of some of these materials produce
dioxins, furans and polychlorinated biphenyls, which have the potential
to cause various types of ailments including cancer.

Practical Manual B.Voc

Megalops cyprinoides

Phylum: Chordata

Class: Actinopterygii

Order: Elopiformes

Family: Megalopidae

Genus: Megalops












In appearance, it is like the Atlantic tarpon, Megalops atlanticus: olive-green on top, and silver on the sides. The large mouth is turned upwards; the lower jaw contains an elongated, bony plate. The last ray of the dorsal fin is much longer than the others, reaching nearly to the tail. It is capable of filling its swim bladder with air and absorbing oxygen from it. Species in fresh water tend to be smaller than the saltwater species, growing just over 50 cm (20 in), while saltwater species grow over a 1 m (3.3 ft). They live an upwards of 44 years and mature within two. They complete their metamorphosis from their larvae stage in 10 days.[2]


Lates calcarifer


Phylum: Chordata

Class: Actinopterygii

Order: Perciformes

Family: Latidae

Genus: Lates





This species has an elongated body form with a large, slightly oblique mouth and an upper jaw extending behind the eye. The lower edge of the preoperculum is serrated with a strong spine at its angle; the operculum has a small spine and a serrated flap above the origin of the lateral line. Its scales are ctenoid. In cross section, the fish is compressed and the dorsal head profile clearly concave. The single dorsal and ventral fins have spines and soft rays; the paired pectoral andpelvic fins have soft rays only; and the caudal fin has soft rays and is truncate and rounded. Barramundi are salt and freshwater sportfish, targeted by many. They have large, silver scales, which may become darker or lighter, depending on their environments. Their bodies can reach up to 1.8 m (5.9 ft) long, though evidence of them being caught at this size is scarce. The maximum weight is about 60 kg (130 lb). The average length is about 0.6–1.2 m (2.0–3.9 ft). Its genome size is about 700 Mb, which was sequenced and published in Animal Genetics (2015, in press) by James Cook University.
Barramundi are demersal, inhabiting coastal waters, estuaries, lagoons, and rivers; they are found in clear to turbid water, usually within a temperature range of 26−30 °C. This species does not undertake extensive migrations within or between river systems, which has presumably influenced establishment of genetically distinct stocks in Northern Australia.