On June 16, the Indira Gandhi International Airport recorded 117.8 mm of rainfall in four and a half hours between 1 p.m. and 5.30 p.m. The water-logging that occurred subsequently forced passengers to wade through knee-deep water, crippled the baggage handling system and affected X-ray machines, elevators and escalators. It was an unfortunate situation for the airport operator — Delhi International Airport Ltd. (DIAL) — as it came a few days after IGI received the title of the second best airport in the world.

What followed was finger pointing between the airport operator, government agencies such as the Public Works Department (PWD) and the Delhi Jal Board (DJB), and villagers in the adjoining areas of Mahipalpur and Rangpuri. While DIAL claimed flight operations carried on unaffected, they attributed the flooding to “choked stormwater drains” on the periphery of the airport. The clogging, they said, was caused due to sewage water entering these drains.

The PWD, which built the peripheral drain, said the airport’s internal drainage system was unable to handle the water. The department said it wanted to see the internal drainage system’s map but the requests were ignored.

For its part, the DJB claimed that the commissioning of its sewage treatment plant in Kapashera has little to do with the airport since it is not for managing stormwater. As for the villagers in the area, they said when pillars were constructed by the National Highways Authority of India (NHAI) for elevated corridors, several drains were broken, leading to acute water-logging in these parts.

DIAL attributed the situation to the “inherent problem of a low-lying area”. It said whenever there is any substantial rain, the stormwater runoff from neighbouring areas flows into the airport’s surface water drainage system.

“There is a 17-metre elevation difference from National Highway 8, which is more than the height of low-rise four-storey buildings in Delhi. This additional surface water runoff from the surrounding area beyond IGI Airport becomes very large and contributes to flooding,” a DIAL spokesperson said.

But since the June water-logging incident, high discharge pumps in various locations have been installed to boost the discharge of standing water in the airport drainage system. A total of 30 dedicated personnel have been deployed near Terminal 3 (T3) to manage the heavy flow of surface water which continues to flow towards the domestic section of T3.

The airport operator has also written to the Delhi Government. “The government has put the responsibility on PWD and NHAI to do the needful and accordingly they have started taking necessary action such as construction of additional drainage line, connection of open drain points and collection chambers. Work is in progress and we hope it would be completed by the end of August,” the DIAL spokesperson said.

Immediately after rain water crippled the airport in June, a joint inspection by the PWD, NHAI and DIAL led to the PWD agreeing to extend the periphery drain from Mahipalpur to Shankar Vihar. The construction of the 1.56-km-long drain from the airport boundary to the existing drain at Mahipalpur junction was for the collection of stormwater from Shankar Vihar and its adjoining areas. “They had asked us (PWD) to extend the drain till Shankar Vihar which we have completed. Despite heavy rain, the laying of the pipes has been completed and stormwater is flowing freely through this drain,” said a senior PWD official.

“We have not seen the internal plan of the airport’s drainage system yet. One way of augmenting the drains’ capacity is to increase the number of groundwater catchment structures along the drains of the airport,” the official said.

In a letter to the PWD secretary earlier this month, DIAL had also requested that cross drains be laid from Shankar Vihar under the NH-8 service road and that these be connected with the peripheral drains. DIAL requested the collection of surface runoff from the road and its diversion into the existing drains. Responding to this, the PWD official said: “Most of these requests fall under the purview of NHAI. The PWD has done its bit in extending the drain that we had agreed to.”

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