is disseminated through the GMDMA( Greater Mumbai Disaster Management Authority) web portal in real-time during the monsoon. Water level measurements can be made on the receiving river or drain using ultrasonic water level sensors. The methodology is to look at the Indian Meteorological Department ' s ' Nowcasting’ forecasts and simultaneously monitor the satellite maps for movement of weather systems. Looking at the satellite animations, one can estimate when heavy rainfall is likely to take place over the city. Once the rainfall takes place, the automatic weather station records the rainfall and simultaneously, the flow gauges record the water level. From the moment the water falls on the rain
gauge to the time it reaches the water body of the affected area, there is a delay of some time. Hence, we have some lead time to inform the people living in the downstream area that the river levels are likely to rise.
Q. What response mechanism should be put in place for help to reach affected people on time?
A. The local community is the first responder in case of most disasters. The second line of responders is the city municipal corporation or the urban local bodies. In Mumbai, the fire and rescue services are within the purview of the Municipal Corporation of Greater Mumbai and they can reach the affected areas within 15- 30 minutes. Other cities can adopt a similar model for help to reach the affected people within a reasonable time.
Q. What is‘ Nowcasting’? How can it be useful in managing urban floods?
A. It refers to real-time weather updates. Earlier, the Indian Meteorological Department( IMD) used to issue warnings twice a day, at 8:30 am in the morning and 5:30 pm in the evening.‘ Nowcasting’ is a more frequent issuing of alerts. Currently, IMD is issuing nowcasting alerts every three hours for the public and every 30 minutes for the aviation industry. The Municipal Corporation of Greater Mumbai issues nowcasting alerts for floods every 15 minutes on its urban flooding website during the rainy season.
Q. India experienced major urban flood in 2005 in Mumbai and then we heard of Srinagar, Kolkata, Surat and most recently, Chennai, Gurugram( Gurgaon), Bengaluru and Hyderabad during 2015-16. What is the major takeaway from these instances?
A. The major takeaway is that no city is safe from flood disasters. Heavy rainfall can occur in any city any time. City authorities and residents should identify flood prone areas and be prepared to tackle flooding. They should take measures to ensure that when heavy rainfall occurs, adequate drainage systems are in place and these are unclogged so that flooding does not occur in the vulnerable areas. Through proper planning and retrofitting of best management practices, we can ma ke our cities more flood resilient.
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November 2016 23 www. smartgovernance. in