First drainage master plan in 40 years ready

Delhi does not receive rainfall comparable to Mumbai or Chennai, but a heavy spell for an hour is enough to inundate major traffic junctions and residential areas. There are over 300 major waterlogging hotspots in the city.

Delhi has 426.55 km of natural drainage and a cumulative length of 3,311.54 km of engineered stormwater drains. There are 201 natural drains in three major basins of NCT of Delhi. But most storm drains have turned into open sewers, choking the flow of water and resulting in waterlogging. Several natural drains are dotted with encroachments.

The problem is, Delhi continues to rely on a nearly four-decade-old drainage master plan made in 1976. The Indian Institute of Technology Delhi's (IIT-D) drainage master plan, prepared for the Delhi government, addresses all these issues and more.

The IIT-D team carried out multiple simulations on effective management of drainage system after collecting data from 11 government agencies. "Using rainfall data, we conducted simulations to see the impact on flooding. The points and locations that get waterlogged were included. We quantified the volume of water that needs to be drained. If the capacity is not in place, they have to change that or they have to change the incoming volume," says Professor IIT-D professor, AK Gosain

"The current practice of puncturing sewer lines and draining sewage into storm drains to deal with blockages should be stopped. DJB should use latest mechanisms such as super suckers for de-clogging sewer lines," the draft drainage master plan says.

Gosain says part of the plan's implementation will start soon.