Heavy rains were experienced by Tamilnadu and Andhra Pradesh states during the second and third week of November 2015 due to the influence of a deep depression over southwest Bay of Bengal. These rains caused major loss to crop and infrastructure in Cuddalore, Kancheepuram, Thiruvallur and Nagapattinam districts in Tamilandu as well as Nellore and Chittoor districts in Andhra Pradesh.

These areas were mapped using images from the Indian microwave satellite RISAT-1 as well as other satellites. Satellite derived maps, showing affected areas, were disseminated to the concerned departments of Central and State Government Ministries. The inundated areas with necessary attribute information are made available on the Bhuvan geo-spatial platform of NRSC, ISRO and also on the “National Database for Emergency Management (NDEM)" portal.

Decision Support Centre at NRSC/ISRO monitored and mapped the event in near real time using satellite data. The following are the glimpses of the efforts:

The first satellite data was acquired on November 11, 2015 from the Microwave Remote Sensing Satellite RADARSAT-2 that showed inundation areas near Chidambaram, Cuddalore district. The satellite data were quickly analysed and the inundation layers were generated and published on Bhuvan platform on near real-time basis. This data with other layers/ attributes clearly highlights the affected areas and helps the local administration for further decision making.

These satellite-based value added maps were disseminated to the users within 6 hours of data acquisition.

Further, regular updates on the status of inundation were also provided using the satellite data acquired on 14 th , 17 th and 22 nd November 2015. Such data / information not only captures the status with respect to previous situation, but also highlights any new areas under problem.

, 17 and 22 November 2015. Such data / information not only captures the status with respect to previous situation, but also highlights any new areas under problem. The affected areas near Chidambaram in Cuddalore district (before and after the event) is highlighted in Fig-1, while Fig-2 depicts the cumulative inundation map of 11 th , 14 th and 17 th Nov 2015 respectively.

, 14 and 17 Nov 2015 respectively. High resolution images from CARTOSAT-2 (1 m spatial resolution) of November 21, 2015 was further acquired over parts of Chennai. Specific information pertaining to residential areas such as Rajarathnam colony, Chennai, and Munuswamy Nagar, Thiruvallur have also been published and provided to local authorities (Fig -3 and 4)

The Bhuvan platform has dedicated online information on all the major disaster events that the country has been facing for the past few years. For example, severe floods in J&K and cyclone HUHUD in 2014, cyclone PHAILIN in 2013, floods in Uttarakhand in 2013, forest fires in Nagaland in 2015 and in Tirupathi in 2014 and earthquake in Nepal in 2015 are some of the recent disasters that have highlighted on this platform. These value added products are directly provided to the user departments on a regular basis to assist them in the required decision making.