Notes: Specific Hazards and Mitigation

(i) The Indian sub-continent is prone to a large number of natural hazards, namely floods, cyclones, earthquakes and landslides, bringing, a huge loss to life, livelihood, property and infrastructure.
(ii) We should try to understand the various structural and non-structural measures that could be taken up by the community, Government and Non-Governmental organisations in pre, during and post disaster phases which would help in creating awareness and be better prepared.

(i) Mitigation refers to any measure taken to minimise the impact of a disaster or potential disaster.
(ii) Mitigation can take place before, during or after a disaster, but the term is most often used to refer to actions taken against potential disasters.

(i) Mitigation efforts help the people by creating safer communities and reducing loss of life and property. Some mitigation measures include
(a) Enforcing strict building codes, flood-proofing requirements, seismic design standards and wind bracing requirements for new construction or for repairing existing buildings.
(b) Construction of houses away from hazardous areas.
(c) Retrofitting public buildings to withstand strong winds or ground shaking.
(d) Building community shelters to help protect people living in areas which are prone to various hazards.

(i) Mitigation creates safer communities by reducing losses to life and property.
(ii) Mitigation enables individuals and communities to recover more rapidly from disasters.
(iii) Mitigation lessens the financial impact of disasters on government and communities.

(i) Structural Mitigation Structural mitigation includes activities such as construction of river embankments or strengthening existing buildings.
(ii) Non-Structural Mitigation Non-structural mitigation includes activities such as training in disaster management, regulating land-life, public education etc.

(i) Floods are temporary inundations of large regions as a result of an increase in water level in a reservoir, or of rivers flooding their banks because of heavy rains, high winds, cyclones, storm surge along the coast, tsunami, melting of snow or dam burst.
(ii) Floods have been a recurrent phenomenon in India with more than 12% of the total land area prone floods. It is necessary to take adequate structural and non-structural mitigation measures.
(iii) Floods can happen both gradually, taking hours, or suddenly due to breach of water control structures, spillover or heavy downpour caused in the region.
(iv) Flood Warning Information is disseminated by the following means
(a) Government Channels
(b) High Priority Telegrams
(c) Doordarshan and Local Cable Channels
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(d) All India Radio
(e) Bulletins in the Press.
(f) Satellite based Disaster Warning Systems
(g) Fax
(h) Telephone

(i) Structural Mitigation
(a) Water-shed Management Timely cleaning, desilting and deepening of natural water reservoirs and drainage channels must be taken up.
(b) Reservoirs The entire natural water storage place should be cleaned on a regular basis, especially before the monsoon reason.
Encroachments on tanks and ponds or natural drainage channels should be removed well before the onset of monsoon.
(c) Building on Elevated Area The buildings in flood prone areas should be constructed on an elevated area and, if necessary, on stilts or platforms.
(d) Natural Water Retention Basins Construction of protection or flood protection embankments, ring bunds and other bunds.
Dams and levees can also be constructed which can be used as temporary storage space, which will reduce the chances of lower plains getting flooded.
(e) Implementing Flood Control measures to reduce flood damage. Measures can be taken to reduce the runoff by reforestation, protection of vegetation, cleaning of debris from streams, etc.
(ii) Non-Structural Mitigation
(a) Mapping of Flood Plains It is the first step involved in reducing risk offloads.
(b) Land Use Control Land use control will reduce the danger to life and property when water inundates the flood plains and coastal areas.
¢ No major development should be permitted in areas which are subject to flooding.
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¢ Important facilities like hospitals should be located in safer and elevated areas.
(c) Flood Forecasting and Warning Better facilities would help in reducing the impact of floods.

(i) Cyclones are violent storms, often of vast extent, characterised by high winds rotating about a calm centre of low atmospheric pressure. This centre moves onward often with a velocity of 50 km pr hour.
(ii) Warning
(a) Cyclones have been recurrent phenomena in the coastal parts of India. Cyclones strike suddenly although it takes time for a cyclone to build up.
(b) Satellite tracking can track the movement, the build up and likely path of a cyclone.
(c) Warning and evacuation are done from along the projected path.
(d) However, landfall prediction can give only a few hours notice to the threatened population, as it is difficult to predict landfall with total accuracy.
(e) The Indian Meteorological Department issues warnings against severe weather phenomena like tropical cyclones, heavy rain and snow, cold and heat wave, etc.
(f ) Warnings is disseminated by several means such as satellite based disaster warning systems, radio, television, fax, high priority telegrams, public announcements and bulletins in the press.

(i) Structural Mitigation
(a) Multi-Purpose Cyclone Shelters Multi-purpose cyclone shelters with suitable designs need to be constructed in appropriate locations in coastal areas.
Cyclone shelters can be used as schools or community centres at normal times.
(b) Engineered Structures Engineered structures that can with stand wind forces need to be built with locally available materials.
¢ It is advised to construct houses on stilts or on earth mounds.
¢ Buildings should be wind and water resistant.
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¢ All elements holding the structures need to be properly anchored to resist uplift or flying off of the objects. e.g, overhangs of roofs should be avoided and projections should be tied down.
(c) Protection Against Wind Construction of houses either behind a mound or hillock and not right on the coast. This will act as a protection against strong cyclonic winds. Fishermen are normally affected as they stay very close to the coastline.
(d) Coastal Belt Plantation Shelter belt plantation along the coastline will mitigate the impact of strong winds. It will also check soil erosion and inward sand drift, thereby protecting cultivated fields and houses which are located in coastal areas.
(e) Construction of Roads Construction of roads which are elevated. The East Coast road from Kolkata to Kanyakumari is one such example.
(ii) Non-Structural Mitigation Measures for Cyclone
(a) Hazard Mapping A hazard map will illustrate the areas vulnerable to cyclones in any given year. It is an effective mitigation tool.
(b) Land use Control Land use control should be designed so that the least critical activities are placed in vulnerable areas. Location of settlements in the flood plains is of most risk. Vulnerable areas should be kept for parks, grazing or play grounds.
(c) Cyclone Forecasting and Warning Better forecasting of cyclones, as well as early and timely warning to the people who are likely to be affected leads to better preparedness and reduced impact to life, property, livelihoods and infrastructure.

(i) An earthquake is a sudden release of energy accumulated in deformed rocks causing the ground to tremble or shake.
(ii) Warning
(a) Earthquake is a sudden onset hazard and can happen at any time of the year, day or night with sudden impact without warning.
(b) There is no foolproof accepted method of earthquake prediction.
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(i) Structural Mitigation
(a) Engineered Structures should be designed and built to withstand ground shaking.
(b) Soil Type must be analysed before construction and structures must not be built on soft soil.
(ii) Non-Structural Mitigation
(a) Enforcing Building Codes
¢ The Bureau of Indian Standards has published building codes and guidelines for safe construction to reduce the impact of earthquakes.
¢ Before the buildings are constructed, the building plan has to be checked by the Municipality to verify if the structure conforms to the building guidelines set by the  government.
¢ Many existing buildings like hospitals, important government offices, schools, fire stations, etc. need to be retrofitted with safety devices based on these guidelines, as they play a very crucial role in case a disaster strikes.
(b) Public Awareness
¢ Sensitisation and training programmes for architects, builders, contractors, designers, engineers, financiers, Government functionaries, house owners, masons, etc.
¢ Reduce possible damage from secondary effects like fire, floods, landslides etc by identifying potential landslide sites and restricting construction in these areas.
(c) Landslides
¢ Landslides are slippery masses of rock, Earth or debris which move by the force of their own weight down slopes or river banks.
¢ Landslides are primarily associated with mountainous terrains; these can also occur in areas such as surface excavations.
¢ Landslides are a major natural disaster in hilly terrains like the Himalaya's, Western Ghats and in the North-Eastern parts of the country. They destroy life and property almost perennially and cause devastating damage to the transportation and communication network.
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(d) Warning
¢ Normally landslides occur gradually; however, at times, sudden failure (sliding) can occur without warning.
¢ They may take place in combination with earthquakes, floods and volcano eruptions.
¢ There are no clearly established warning systems in place indicating occurrence of landslides and hence they are difficult to predict.
¢ Areas of high risk can be determined by use of information on geology, hydrology regulation cover past occurrence and consequences in the region.
¢ Since most of the landslides occur without prior warning, there is a need to be better prepared and carry out certain mitigation measures to reduce the impact.

(i) Structural Mitigation
(a) Drainage Corrections
¢ The most important triggering mechanism for mass earth movements is water infiltration into the land area during rains.
¢ Hence, the natural way of preventing this situation is by reducing water infiltration and allowing excess water to move down without hindrance.
¢ In such a situation, the first and foremost mitigation measure is drainage correction. This involves maintenance of natural drainage channels, both micro and macro, on vulnerable slopes.
(b) Engineered Structures with strong foundation can withstand ground movement forces. Underground installations (pipes, cables, etc) should be made flexible to move in order to withstand forces caused by landslides.
(c) Retaining Walls Retaining walls can be built to stop land from slipping (these walls are seen along roads in hill stations.)
(d) Increasing Vegetation Increasing vegetation cover is the cheapest and most effective way of arresting
(stopping ) landslides. This helps to bind the top layer of the soil with layers below, while preventing excessive water run off and soil erosion.
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(ii) Non-Structural Mitigation
(a) Hazard Mapping Hazard mapping will locate areas prone to slope failures. This will identify avoidance of areas for building settlements.
(b) Land Use Practices Land use practices such as preserving existing natural vegetation (forest and natural grassland) in good condition should be adopted.
¢ Denuded upper slopes must be reforested with suitable tree species.
¢ In construction of roads, irrigation canals, etc proper care is to be taken to avoid blockage of natural drainage.
(c) Awareness Generation The public should be educated about signs that a landslide is imminent, so that personal safety measures may be taken and also gathering information or indigenous methods used to reduce the impact.
(d) Drought Drought is a climatic anomaly, characterised by deficient supply of moisture resulting either from sub-normal rainfall, erratic rainfall distribution, higher water need or a combination of all the factors.
(e) Onset
¢ Drought is a slow onset disaster and it is difficult to demarcate the time of its onset and its end.
¢ Its effects often accumulate slowly over a considerable period of time and may linger from months to years after the termination of the event.
(f) Warning According to the Indian Meteorological Department, the country is said to be drought affected when the overall rainfall deficiency is more than 10%
of the long period average and more than 20% of the country’s area is affected by such drought conditions.
Falling rainfall levels, falling ground water levels, drying wells, rivers and reservoirs, and poor agricultural production warn of the onset of drought.
¢ In general, drought means different things to different people.
¢ To a meteorologist, it is the absence of rain while to the agriculturist it is the deficiency of soil moisture in the crop root zone to support crop growth and productivity. To the hydrologist, it is the lowering of water levels in lakes, reservoirs etc, while for the city management, it may mean the shortage of drinking water availability. Thus, it is unrealistic to expect a universal definition of droughts for all fields of activity.

Drought preparedness, with appropriate mitigation actions and programmes, can reduce and in some cases, eliminate much of the impact associated with drought .
(i) Structural Mitigation
(a) Revival of traditional water harvesting structures, like canals, tanks, etc. In Gujarat, 'Jhalara’, also known as 'Baolis' in Rajasthan are some examples of traditional water harvesting structures in India.
(b) Construction of water harvesting structures, in houses and farm areas. Water harvesting can be carried out by either allowing the runoff water from all the areas to a common point or allowing it to infiltrate into the soil, thereby increasing the ground water level.
(ii) Non-Structural Mitigation
(a) Drought Monitoring
¢ Monitoring and early warning essentially provides the foundation on which timely decisions can be made by decision makers at all levels (i.e., farmers to national policy makers).
¢ Given drought's slow onset or creeping characteristics, monitoring all components of the hydrological system is the only mechanism for detecting drought's early onset and its potential impacts on sectors, regions and populations.
(b) Drought Awareness Programmes In areas that are normally affected by drought, Government, and Non-Government Organisations (NGOs), local corporates and other key players have taken the initiative to bring awareness on water conservation, livelihood planning, land use planning, traditional water conservation strategies, etc.
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(c) Land Use Planning Land use based on its capability helps in optimum use of land and water, and can prevent undue demand created due to misuse.
(d) Livelihood Planning It identifies those livelihoods which are least affected by drought. Some livelihoods that are normally practiced in areas which are affected by drought include collection of non-timber forest products from the community forest, carpentry, raising goats etc.
(e) Crop Insurance This is an insurance given to the farmers who have lost their crops because of lack of water supply.

(i) Twenty years ago, this village showed all traits of abject poverty. It practically had no trees, the topsoil had blown off, there was no agriculture and people were jobless.
(ii) Anna Hazare, one of India’s most noted social activists, started his movement, concentrating on trapping every drop of rain, which is basically a drought mitigation practice.
(iii) The villagers built check dams and tanks. To conserve soil they planted trees. The result was that from 80 acres of irrigated area two decades ago, Ralegaon Siddhi has a massive area of 1300 acres under irrigation today.
(iv) The migration for jobs has stopped and the per capita income has increased ten times from ` 225 to 2250 in this span of time. No World Bank funding, no government grants, only people's enterprise.