Disaster Management Support Programme
India has been traditionally vulnerable to natural disasters on account of its geo-climatic conditions. Floods, droughts, cyclones, earthquakes and landslides have been recurrent phenomena. About 60% of the landmass is prone to earthquakes of various intensities; over 40 million hectares is prone to floods; close to 5,700 km long coastline out of the 7,516 km, is prone to cyclones; about 68% of the cultivable area is susceptible to drought. The Andaman & Nicobar Islands, the East and part of West coast are vulnerable to Tsunami. The deciduous/ dry-deciduous forests in different parts of the country experience forest fires. The Himalayan region and the Western Ghats are prone to landslides.
Under the DMS programme, the services emanating from aerospace infrastructure, set up by ISRO, are optimally synthesized to provide data and information required for efficient management of natural disasters in the country. The Geostationary satellites (Communication and Meteorological), Low Earth Orbiting Earth Observation satellites, aerial survey systems together with ground infrastructure form the core element of the observation Systems for disaster management.
The Decision Support Centre established at National Remote Sensing Centre (NRSC) of ISRO is engaged in monitoring natural disasters such as flood, cyclone, agricultural drought, landslides, earthquakes and forest fires at operational level. The information generated from aero-space systems are disseminated to the concerned in near real time for aiding in decision making. The value added products generated using satellite imagery helps in addressing the information needs covering all the phases of disaster management such as, preparedness, early warning, response, relief, rehabilitation, recovery and mitigation.
India is one of the most flood prone countries in the world. Floods occur in almost all rivers basins in India. Twenty-three of the 35 states and union territories in the country are subject to floods and 40 million hectares of land, roughly one-eighth of the country’s geographical area, is prone to floods. Assessment of the extent of flood affected areas and the damage to the infrastructure will enable the decision makers to plan for relief operations. Satellite based imageries due to their synoptic coverage are the best tool to assess the extent of flood affected areas. As soon as the information of a flood event is obtained, the earliest available satellite is programmed to collect the required data for the delineation of flooded areas. Both optical and microwave satellites data is being used. The inundation maps with flooded and non-flooded areas marked in different colours along with the affected villages and the transport network are disseminated to the concerned Central / State agencies. Using the historical data of floods affecting different areas flood hazard zonation is being carried out. Such district level hazard atlases have been prepared for Assam and Bihar States. Further, integrating the information on the river morphology generated from aerial surveys, weather forecast and the in-situ data from CWC, flood forecasting methodologies have been generated and being operationalised.
The major natural disaster that affects the coastal regions of India is cyclone. India has a coastline of about 7516 kms and it is exposed to nearly 10% of the world’s tropical cyclones. About 71% of this area falls in ten states (Gujarat, Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu, Puducherry, Andhra Pradesh, Orissa and West Bengal). The islands of Andaman, Nicobar and Lakshadweep are also prone to cyclones. On an average, about five or six tropical cyclones form in the Bay of Bengal and Arabian sea and hit the coast every year. When a cyclone approaches to coast, a risk of serious loss or damage arises from severe winds, heavy rainfall, storm surges and river floods. Using appropriate models and satellite data, ISRO is supporting the efforts of India Meteorological Department to predict the tropical cyclone track, intensity and landfall. After the formation of cyclone, its future tracks are regularly monitored and predicted on an experimental basis using a mathematical model, developed at Space Application Centre, ISRO. These experimental track predictions are regularly posted on departmental web portal (http://www.mosdac.gov.in/scorpio/) as part of information dissemination. Using the wind pattern generated by the Oceansat-2 Scatterometer data models have been developed for predicting the formation of a cyclone even before the depression turns into a cyclone. Such cyclogenesis predictions are being carried out for all the global cyclones and uploaded to the portal.
With more than 70 percent of India’s population relying directly or indirectly on agriculture, the impact of agricultural drought on human life and other living beings is critical. In India, around 68% of the country is prone to drought in varying degrees. Of the entire area, 35% receives rainfall between 750 mm and 1125 mm, which is considered as drought prone and 33%, receives rainfall less than 750 mm, which is considered to be chronically drought prone. Coarse resolution satellite data, which covers larger areas, is used to monitor the prevalence, severity level and persistence of agricultural drought at state/ district/ sub district level during kharif season (June to November). The operational methodology developed by ISRO over the years is now institutionalized by setting up Mahalanobis National Crop Forecasting Centre (MNCFC) under the Ministry of Agriculture. Currently, ISRO is concentrating on upgrading the methodology for monitoring the drought and efforts are on to develop early warning systems for agricultural drought.
Nearly 55% of the total forest cover in India is prone to fires every year. An estimated annual economic loss of Rs.440 crores is reported on account of forest fires over the country. Forest fires in India have environmental significance in terms of tropical biomass burning, which produces large amounts of trace gases, aerosol particles, and play a pivotal role in tropospheric chemistry and climate. Active forest fires are detected from the satellite images and the information is uploaded daily to the Indian Forest Fire Response and Assessment System (INFFRAS) website during the forest fire season – February to June (www.inffras.gov.in).
Remote sensing data have been proved to be useful for landslide inventory mapping both at local and regional level. It is also used for generating maps such as lithology, geological structure, geomorphology, land use / land cover, drainage, landslide scarp, etc. These maps can be combined with other terrain maps like slope, slope aspect, slope morphology, rock weathering and slope-bedding dip relationship in GIS environment to map the vulnerable areas for landslides. Department of Space has prepared Landslide Hazard Zonation maps (LHZ) along tourist and pilgrim routes of Uttaranchal and Himachal Pradesh, Himalayas and in Shillong-Silchar-Aizwal sector. As a part of the DSC activity all the major Landslides are being monitored for damage estimation.
Remote Sensing and GIS provide a database from which the evidences left behind by disaster can be combined with other geological and topographical database to arrive at hazard map. The area affected by earthquakes are generally large, but they are restricted to well known regions (Plate contacts). Satellite data gives synoptic overview of the area affected by the disaster. These data can be made use to create a very large scale base information of the terrain for carrying out the disaster assessment and for relief measures.