The floods of 26 July 2005 were a wake-up call, recalls Mahesh Narvekar, chief officer of the disaster management cell of the Municipal Corporation of Greater Mumbai (MCGM). “Before that, the maximum rain the city had ever seen was 500mm, and suddenly, that year we were swamped by 944mm.”
The flood claimed 445 lives and brought with it an urgent realization that Mumbai needed to get its act together.
This has been the story of disaster management across India.
A series of crises in the 2000s—the Gujarat earthquake of 2001, the tsunami of 2004, the terror attack on Mumbai in 2008—served to propel disaster management in India to a higher level. The Disaster Management Act of 2005 proposed setting up a national authority, which, in turn, has made the use of technology in managing emergencies widespread. “None of the technologies you need at any stage are rocket science,” says Raghu Raman, an expert on homeland security and a columnist for Mint.
“They have all been around for a while, right from satellite phones to thermal imaging. The trouble was always deployment.” But India has caught on.
One of the most critical technologies needed in every stage from assessment to recovery is remote sensing—gathering data about an object without physical contact. Here is where the Indian Remote Sensing (IRS) satellite programme comes in.
IRS’ nine satellites make up the largest remote sensing constellation for civilian use anywhere in the world. Following the Mumbai terror attacks of November 2008, India launched the Risat-2, a spy satellite with synthetic aperture radar (SAR) that allowed for very fine spatial resolution in images, in April 2009.
Risat-2 can see through thick cloud cover, rain, snow, fog or even camouflage-like foliage.
This allows all-weather monitoring of movement across India’s borders with Pakistan, Bangladesh and China.
Prior to this, India depended on US satellites such as Ikonos for the same information. “Almost all defence satellites also have weather mapping capabilities,” says Raghu Raman, “for defence purposes, knowledge of weather patterns is essential.” India’s Cartosat series of satellites, for example, combine military and civil capabilities for disaster management support. With each subsequent launch, these satellites have gone up in resolution. IRS’ 17th and the latest in the series is Cartosat 2B, launched in July. It carries a panchromatic camera with a spatial resolution of 1m and covers a swath of 9.6km per camera.
This means, each pixel in the satellite’s image would represent about 1 sq.m.
So how do these satellites help with disaster preparedness? One way is through hazard zoning—mapping areas that are at risk. Cartosat 2B can image the geology of flood-prone terrains and human settlements in them.
This, in combination with other data like demographics and a history of flooding, can help in creating rescue plans.
Remote sensing is supplemented by multiple other instruments that can detect changes in weather phenomena. Tsunami buoys, for example, can detect changes in water pressure, which could indicate an incoming tsunami. MCGM’s disaster management cell has commissioned the Indian Institute of Technology, Mumbai to study peak-ground acceleration (PGA)—a measure of how hard the ground shakes in an earthquake. “While we have identified 48 incidents where we have to respond in Mumbai, we are going to focus on earthquakes and flood,” said Narvekar.
“This PGA study maps out scenarios according to time location and scale. So we would know exactly what would happen if an earthquake of intensity 6.5 on the Richter scale struck at 10 in the morning at Panvel, in terms of injury, death toll and economic loss.”
Prior to the July 2005 floods, Mumbai had only two automated weather systems, a situation that the MCGM remedied after the experience.
“Today, we have 35 weather stations in 29 catchments. We have software giving us warnings when the rainfall touches 15mm in 10 minutes or 20mm in 15 minutes, etc., and we work on the assumption that we will now receive more than 40mm in one hour or 50 in one hour.”
“Communication is the first thing to go down in a crisis as people start jamming cell phone networks. It is also the most powerful force multiplier in rescue and relief,” says Raghu Raman. Once a warning is sounded, it has to be disseminated to groups that will take action. After the terror attacks, Mumbai enhanced its communication systems and set up hotline connectivity with key players—the Mumbai Metropolitan Region Development Authority (MMRDA), police, Navy, Army and central western railway, among others.
In Chennai, which faced the devastating tsunami in 2004, an external siren-based warning system along the coastline is being built with World Bank funds. A seamless radio communication network is also being rolled out in Ramnad district for fisheries.
Some of Tamil Nadu’s existing systems served a critical role during the tsunami, says Santosh Babu, managing director of Electronics Corporation of Tamil Nadu Ltd (Elcot) and the chief architect of its very high frequency (VHF) and high frequency (HF) radio networks.
“The HF radio system provides a voice network that connects the entire revenue administration with the 12 district collectors as well as their camp offices and the district collectorates from Chennai without the need for any repeater system. This network is capable of working independent of TN Police or any other network,” says Babu.
The intra-district communication network uses VHF radios by Kenwood. “The radios were tested and worked very well during the Dec-2004 tsunami and post- tsunami relief operations in the Cuddalore and Nagapattinam,” he adds.
Redundancy in communication systems is a necessity in the event of a disaster. Tamil Nadu supplements its very high frequency and high frequency radio systems with a wide area network that can support Internet telephony, again an alternative in times of cell-network jamming.
Mapping the disaster
Both Mumbai’s disaster management cell and Elcot are focusing on geographic information systems (GIS) to allow for quick response. Mumbai’s GIS is due to be ready in about eight months. “We already have a basemap of 2004 and data from a survey carried out in 2009. We will now do a physical survey and superimpose the three to create a GIS,” says Narvekar. The GIS will map all above-ground utilities—buildings, electric poles, trees, petrol pumps, hospitals, water pipelines and so on. Further, these utilities will have a number of attributes—hospitals, for examples, will show the number of beds, doctors and nurses, specializations, mortuaries, blood banks and vaccination capability.