Ways in which remote sensing and GIS help in disaster mitigation and management

Geographic Information System (GIS) is a computer based application of technology involving spatial and attributes information to act as a decision support tool. It keeps information in different layers and generates various combinations pertaining to the requirement of the decision making. GIS has emerged as an effective tool in management of disasters since, geo-spatial data and socio-economic information need to be amalgamated for the better decision making in handling a disaster or to plan for tackling a disaster in a better way. GIS could be utilized by the different line departments and agencies who are stakeholders in the disaster management process. Some basic hardware like computer system, printer, network systems, along with GIS software are required to set up the GIS in any organisation.
The prime objectives of developing the GIS database are to help disaster managers at local and regional levels for:

1. Pre-disaster planning and preparedness
2. Prediction and early warning
3. Damage assessment and relief management

GIS combines layers of information on various themes to enable the managers to take the most appropriate decisions under the given circumstances. For disaster management, a GIS database could be a useful managerial tool for the reasons listed below:

1. Disaster Managers could generate maps both at micro and macro level indicating vulnerability to different extents under different threat perceptions.
2. Locations likely to remain unaffected or remain comparatively safe could be identified.
3. Alternate routes to shelters, camps, and important locations in the event of disruption of normal surface communication can be planned
4. Smooth rescue and evacuation operations could be properly planned.
5. Rehabilitation and post-disaster reconstruction works could be properly organized.
6. Locations suitable for construction of shelters, godowns, housing colonies, etc. can be scientifically identified.
7. Areas where no construction should be taken up or existing habitations require relocation, could be identified.

Department of Space (DOS, India) has embarked upon the Disaster Management Support to extend the benefits of the aerospace technology for the resolution of disaster management in the country. The Decision Support Centre (DSC) established at National Remote Sensing Centre (NRSC) is the single window delivery point for aerial and space enabled inputs together with other important data layers for its use in disaster management of pre-disaster, during-disaster and post-disaster phases. The natural disasters being addressed are  Flood, Cyclone, Agricultural Drought, Forest Fire, Earthquake and Landslide. Depending upon the satellite pass, cameras are tilted and data is acquired and analysed. The information is monitored on a regular basis for damage assessment. DSC has provision to mobilize aircraft equipped with Synthetic Aperture Radar (SAR), Air-borne Laser Terrain Mapping unit (ALTM) and High Resolution Digital Camera for obtaining aerial data. DSC is working on space inputs for long-term disaster mitigation and rehabilitation. Use of remote sensing data for various natural disasters is discussed below:

FLOOD: To keep watch on the flood situation in the country through hydrological and meteorological information from various sources, mapping & monitoring of major flood/cyclones with the satellite data from optical and microwave satellites, Generation of flood maps showing flood. The most flood-prone areas in India are the Brahmaputra, Ganga and Meghana River basins in the Indo-Gangetic-Brahmaputra plains in North and Northeast India. ISRO/DOS is playing a vital role in supporting the flood management activities, by providing space as well as aerial remote sensing based services and products. Using satellite data from Indian Remote Sensing Satellite (IRS) System and from foreign satellites, the impact of floods in the country is assessed. The services provided in this context include:

1. Near Real Time Flood Mapping and Monitoring
2. Flood Damage Assessment
3. Flood Hazard Zone Mapping
4. River Bank Erosion Mapping and
5. Mapping changes in the river course

CYCLONES: Cyclones are wind-systems of relatively low pressure which spiral inwards towards a centre in the lowest atmospheric levels and cause immense destruction and loss of life when they strike coastal areas. Satellite communications provide an effective mechanism for real-time dissemination of information and early warning besides establishing communication link after cyclone hit. Earth observation satellites enable continuous monitoring of atmospheric as well as surface parameters. Information acquired by satellite remote sensing covers wide area, periodicity and spectral characteristics and especially in the easiness to compare the data before and after a disaster.

DROUGHT: Agricultural drought assessment using space technology inputs has been operational in India since 1989, through a project 'National Agricultural Drought Assessment and Monitoring System (NADAMS)'. NADAMS provides near real-time information on prevalence, severity level and persistence of agricultural drought at regional and local levels through remote sensing.

FOREST FIRES: Indian Remote Sensing Satellite images were acquired and processed to monitor the forest fire incidence. The Decision Support Center (DSC) is established at National Remote Sensing Centre (NRSC) as part of Disaster Management Support Programme of Department of Space (DOS), for working towards effective management of disasters in India. A comprehensive Indian Forest Fire Response and Assessment System (INFFRAS) is invoked under DSC activities of NRSC, which integrates multi-sensor satellite data and ground data through spatially and temporally explicit GIS analysis frame work. This system provides information on:

1. Fire alerts
2. Fire progression
3. Burnt area assessment and
4. Forest fire mitigation plans

Bhopal gas tragedy as a chemical industrial disaster

On the night of December 2, 1984, the chemical, methyl isocyanate (MIC), spilled out from Union Carbide India Ltd’s (UCIL’s) pesticide factory turned the city into a vast gas chamber. People ran on the streets, vomiting and dying. This was India’s first (and so far, the only) major industrial disaster. This was a chemical industrial disaster and the Government had no clue how to respond in this case. The US-based multinational company, Union Carbide Corporation (UCC), which owned the plant through its subsidiary UCIL(Union Carbide India Limited), failed to deal with the human tragedy.

Bhopal was struck by two tragedies: the one that happened immediately, and the other that unfolded in the years that followed.

The problem was nobody knew much about the toxin or its antidote. Within weeks of the accident many claimed that people were suffering from common ailments of the poor, such as tuberculosis and anaemia. However, till date nobody knows the health impacts of MIC and how to treat patients exposed to the gas. The children born after the disaster are also its victims because of exposure to the deadly gas while they were in their mothers’ wombs.
Additionally, chemical wastes remain dumped in and around the premises of UCIL factory, contaminating the water that people drink.
Union Carbide used trade secrecy as a prerogative to withhold information on the exact composition of the leaked gases. MIC, when reacts with water at high temperatures and releases as many as 300 highly toxic chemicals.
In the first few days, there was evidence that people could be suffering from cyanide poisoning—intravenous injections of sodium thiosulphate, an antidote, imagewas found to be working on the patients. But soon, it was discontinued.

In 1989, UCC paid some US $470 million (worth Rs 750 crore that year) as compensation for the disaster. This was one-seventh of the original demand from the Indian government. However, all civil and criminal cases against the company were terminated. Later, it was realised that many more were suffering from exposure to the poisonous gas. So, when the case was decided, compensation was doled out to virtually the entire city. The final settlement was less than Rs 15,000 per victim.

Bhopal disaster 2.0

The factory used to manufacture three pesticides: carbaryl (trade name Sevin), aldicarb (trade name Temik) and a formulation of carbaryl and gamma-hexachlorocyclohexane (g-HCH), sold under the trade name, Sevidol. For 15 years till the disaster, it dumped process wastes, by-products, solvents, sub-standard products, wastes from machinery and polluted water at dump sites inside and outside the plant. Another 350 tonnes of waste has been kept in a leaking shed at the site. These wastes are still lying at the site, polluting soil and groundwater. This second legacy—Bhopal Disaster 2.0—now threatens even a larger number of people than the first one. Many of the chemicals degrade slowly and are likely to remain in the environment for hundreds of years. They will keep spreading unless they are taken out and the site is decontaminated.

Most studies found groundwater surrounding the UCIL site to be contaminated with chlorinated benzenes and HCH isomers. Carbaryl, aldicarb, carbon tetrachloride and chloroform were also detected in some studies. All these can be linked to the wastes dumped by UCIL plant.

The Union government asked Dow to deposit Rs 100 crore for environmental remediation. Dow has continued frantic lobbying to get the Indian government to withdraw its application.

The disaster had impacts far beyond the boundary of the ill-fated city and its people. It made a difference worldwide to the way that chemical and hazardous waste management was reinforced; workers’ safety precautions mandated; and legislation for environmental management strengthened. Perhaps, this is why we have not seen another Bhopal-like disaster in the past 30 years.

After 30 years, the government of India is still struggling to establish the liability of UCIL, its parent company UCC and its buyer, Dow Chemical.

Differences between human induced and human made disasters

Differences between Human induced and Human made disasters
The primary difference between human induced disasters is that human induced disasters happen unintentionally while human made disasters are intentional. This difference is illustrated below with the help of an example.

Love canal disaster can be termed as a human induced disaster while pollution of the air affecting the health of the population can be termed as a human made disaster.

The love canal tragedy occurred when the toxic chemicals buried underground by the hooker chemical company contaminated the groundwater. The company responsible for this tragedy did not do it on purpose. Hence this disaster can be classified as a human induced disaster.

The increased usage of automobiles in urban areas, has resulted in a very high concentration of pollutants. These pollutants pose a great health risk to new born babies and the elderly. Some of the consequences of this are lung infections, reduced immunity and lack of concentration. Growing population and urbanisation has made this a human-made disaster as this is being done intentionally.

Effects of a major power breakdown

Electricity plays an essential role in our lives. We require electricity for almost all our daily activities at work or home. Failure of electricity or power breakdown paralyses our lives. Power breakdown has been experienced by everyone. Failure of companies to supply electricity to a large area or city for an extended duration is termed as a major power breakdown. The various effects of a major power breakdown are listed below:

1. Inability to use any appliance (at home or work) that depends on electric power. Example: Iron box, Grinding machine, Fans, Lights, AC's, etc., at home and Computers, Copying machines, AC's, Lights, etc., at work
2. Farmers and residents will be unable to use electric pumps to draw water from wells
3. Traffic lights will be non-operational in the affected area causing chaos and leading to traffic accidents
4. Health services will be interrupted and all medical equipment depending on electric power will be non-operational leading to trauma and possible loss of life.
5. A major power breakdown will have a severe negative effect on the socioeconomic fabric of the society
6. Major power breakdowns cause severe financial losses to the Government and private industries.

Risk and Vulnerability in the context of disaster management

RISK is generally defined as the expected impact caused by a particular phenomenon. It combines the likelihood or possibility of a disaster happening and the  negative effects that result if the disaster occurs. Risk is hazard multiplied by vulnerability less the capacity of the population to cope. Risk is defined as the probability of a damaging event or circumstance.

Vulnerability is the extent to which an individual, community, sub group, structure, service or geographical area is likely to be damaged by the impact of a particular disaster. The factors that influence vulnerability include physical, economical, social, political, technical, idealogical, cultural, ecological, institutional and organisational. Vulnerability is the potential for experiencing loss.

Vulnerability is comprised of three elements:

1. Exposure: It is the degree of risk of an event experienced in daily life from the probability of a hazard to actual occurrences of events of all sizes.
2. Resilience: It is the ability to recover, ranging in degree from simply achieving stability at any level of functioning to recovering the full range of resources and positive momentum that existed prior to the event
3. Resistance: It is the ability to withstand the impacts and continue to function.