CHENNAI: The biggest challenge for the authorities while tackling ‘Gaja’, was lack of rainfall data. The State Emergency Operation Centre (SEOC) from where top government officials and the National Disaster Response Force (NDRF) were monitoring the relief and rescue operations in Nagapattinam, Thiruvarur, and other coastal districts, was clueless about which areas were receiving how much rainfall when the storm made the landfall.
But this may change as the State government is planning to have 1,300 telemetry rain gauges at firka or sub-divisional level. This will provide authorities data on a real-time basis and also send alerts through SMS to those in need, as these rain gauges will be GPRS and GSM-enabled.
K Satyagopal, Commissioner of Revenue Administration, told Express that a GO has been passed and Tamil Nadu Urban Infrastructure Financial Services Limited (TNUIFSL) had been asked to finalise the terms of reference.
“We are planning to implement the project in Public-Private Partnership mode. Without government making capital investment, a private firm will be asked to install and maintain the rain gauges and government will procure the data,” he said, adding TNUIFSL was preparing the proposal.
Maharashtra and Karnataka have successfully implemented this model. Among major cities in South India, Chennai has a dismal number of Automatic Rain Gauges (ARGs) and Automatic Weather Stations (AWSs) that relay rainfall information on a real-time basis.
For river basins - Adyar, Cooum, Kosasthalaiyar and Kovalam - combined, that form a gigantic Chennai river basin, which is spread across 4,000 sq km, there are only 17 ARG/AWS. In contrary, the Bengaluru Urban District, measuring 2,190 sq km, has 82 ARGs and in smaller places like Hyderabad, there are 26.
Rajendra Ratnoo, Commission of Disaster Management, accepted that it was a huge grey area.
“Currently, what IMD gives is 24-hour rainfall, but we need hourly data, especially during extreme weather events like 2015 December floods or Cyclone Gaja, to make optimum utilisation of available resources and mobilising ground teams,” he said.
Though Tamil Nadu has good coverage of ARGs installed by Tamil Nadu Agriculture University (TNAU), over 60 per cent remain defunct. Ratnoo said discussions have been initiated with TNAU on how to sort out the issue and integrate their ARGs with the disaster management cell. When contacted, a senior IMD official said the met office can only set up a certain number of AWS required to deliver meteorological services.
“The governments of Karnataka, Maharashtra and Telangana have put up a good network of AWS/ARGs, which should be emulated by the TN,” he said.
Chennai alone needs 44 ARGs
As per the National Disaster Management Authority (NDMA) guidelines prepared in 2010 on ‘Management of Urban Flooding’, there should one ARG for every 4 sq km and the Chennai core area, which is about 176 sq km requires at least 44 ARGs.
The guidelines document said the lack of spatial and temporal rainfall data over urban areas on a real-time basis is a very critical gap. Therefore, the establishment of local networks for real-time rainfall data has to be accorded the highest priority. This will be immensely useful for a much improved early warning, resulting in better response and management of urban flooding. Such rainfall data will also enable robust designing of urban drainage infrastructure in future.