Ageing drainage plan blunts Delhi rain response again
Delhi can be divided into three large drainage basins -- Najafgarh, Trans-Yamuna and Barapullah. The consultant for the revamp of the Najafgarh basin is likely to be appointed by October, while the process to hire the consultants for the other two basins will be initiated later, a Public Works Department official aware of the matter said.
Two days of incessant rains have left Delhi struggling with waterlogged arterial stretches and traffic snarls. The weather department has predicted more rain over the next few days, but the city, operating on a 46-year-old drainage master plan, will have to wait at least till next year for an upgrade of its drainage system.
Delhi can be divided into three large drainage basins -- Najafgarh, Trans-Yamuna and Barapullah. The consultant for the revamp of the Najafgarh basin is likely to be appointed by October, while the process to hire the consultants for the other two basins will be initiated later, a Public Works Department official aware of the matter said.
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According to estimates by the PWD, which was appointed by the government as the nodal agency for the implementation of Delhi’s drainage master plan, the city’s drainage system can cater to a maximum of 50mm rainfall over a 24-hour period. Anything more than that overwhelms the system, resulting in the flooding of arterial roads.
At present, there are eleven agencies in Delhi that oversee a network of natural and engineered stormwater drains. During spells like the one Delhi has seen over the past three days, when the city received 106mm of rain (between 8.30am on Thursday and 8.30pm on Saturday), the plan begins to show its age.
The upgrading of the city’s 1976 drainage master plan remains a work in progress. In 2009, the then lieutenant governor, Tejendra Khanna, had asked the civic agencies and all stakeholders to prepare a new master plan for Delhi’s watershed and drainage system.
After finding the drainage master plan prepared by Indian Institute of Technology Delhi generic, the government had last year appointed PWD as the nodal agency for the implementation of the project to turn the IIT report’s recommendations into actionable intervention points to solve waterlogging problems.
The first attempt to hire a consultant for the implementation of a drainage master plan resulted in no eligible takers, and the process was subsequently revised, the PWD official said, seeking anonymity. In March, the Delhi government announced that it will appoint two consultants -- overseeing the Najafgarh, and the Trans-Yamuna and Barapullah basins -- to prepare a blueprint for augmenting the existing drainage systems and to monitor the implementation of the new master plan.
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“In the second attempt, we have received bids from candidates and they are in the final acceptance phase. We will need financial sanction to go ahead with the process. The consultant for Najafgarh basis is likely to be in place by October-end. Tenders for other two basins have not been called yet. However, the actionable points should be ready before next monsoon,” the PWD official said.
While the process to upgrade the drainage master plan is likely to take much longer, the PWD has stated that it has taken corrective steps in terms of capacity enhancement and engineering solutions on 13 critical waterlogging points like the underpasses at Minto Road and Pul Prahladpur.
“These critical sites have managed to remain waterlogging-free despite heavy rainfall. In the second phase, we have asked all the zones to submit proposals for engineering solutions at the vulnerable waterlogging points in their areas by September 30, and many of these proposals are already in,” he added.
