D.V.L Padma Priya

GHMC to create inventory of stormwater drains

150 rain gauges to be installed in the city

HYDERABAD: The National Disaster Management Authority (NDMA) has initiated a flood impact assessment study in the city aimed at mitigating urban flooding.

NDMA member and legislator M. Shashidhar Reddy told The Hindu that the study, said to be the first-of-its-kind in the country, was being taken up together with the State government and Greater Hyderabad Municipal Corporation (GHMC).

It would include research on average rainfall recorded over a period of time keeping in mind the ‘Heat Island Effect’ and specifically map the worst-affected areas that got flooded in short duration of time during heavy downpours, he said.

The GHMC would create an inventory of stormwater drains on its part and “this will enable us to determine the capacity of existing stormwater drains and comparing it with rainfall received, develop estimates of capacity up gradation,” the MLA said.

Mr. Reddy said stormwater drainage system should be a part of natural waterway and this aspect was given little thought by planners. “Any local body is supposed to keep track of sewerage system. However, keeping a track of stormwater drains seems to be nobody’s business.”

Emphasising the need for more rain gauges, he said the existing gauges were unable to provide information to help answer vital questions - where it rained and how much. As part of the study, GHMC would install 150 rain gauges within the city limit. “This network will be coordinated in a control room and authorities will have ample time to alert people living in low-lying areas prone to flooding,” he said, pointing out that a similar network in Mumbai of 35 rain gauges played a crucial role in mitigating urban flooding.

Training needed

Absence of a properly designed and maintained stormwater drainage system too was one of the causes for urban flooding, he said. “Unlike other countries, India doesn’t even have a stormwater manual and guidelines laid down by the Ministry of Urban Development are hardly looked into,” he said adding that there was a need to impart specific training to engineers who are handling urban infrastructure.

Apart from this, the study will also involve collating information on various structures in the city such as flyovers, high-rise buildings, etc, and Aerial Land Terrain Mapping (ALTM) from National Remote Sensing Agency and inputs from a Doppler Weather Radar to be installed shortly. “The information gathered will be used for real-time modelling using advanced software which will then help us to build a flood impact assessment framework,” he said. The study had been estimated to cost Rs. 27 lakh and was expected to be finished in 12 months.