The Public Works Department (PWD) has initiated a new approach to constructing stormwater drains across Delhi, requiring the use of precast drainage boxes instead of the traditional in-situ casting method, an official familiar with the development said on Saturday.
The transformation is part of the ongoing city-wide drainage reconfiguration in line with the Drainage Master Plan, for which 20 tenders have already been invited. The official said that work has begun in Shalimar Bagh and is expected to expand to other parts of the city in phases.
Faster execution, improved durability
Precast drainage boxes improve durability, reduce construction time and reduce on-site pollution. Moreover, unlike the traditional in-situ casting method, where raw materials such as cement, sand and aggregate are mixed and poured directly at the construction site, precast drainage boxes are manufactured in controlled factory settings.
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“The biggest advantage of precast drainage boxes is uniform quality and faster implementation. These structures are manufactured off-site, which significantly reduces the time taken for installation and reduces disruption on roads,” said PWD Minister Parvesh Verma.
50 year lifespan and reduced turbulence
Precast drain boxes also come with a 50-year warranty, providing a longer lifespan compared to traditional drains.
“We are adopting modern construction techniques to ensure that stormwater drains are built faster, last longer, and cause minimal inconvenience to the public,” the minister said.
However, officials clarified that the transition is not absolute. A hybrid model is being followed to address conditions on the ground. While precast drain boxes are deployed on spans with straight drain lines, the cast-in-place method continues to be used for curves or complex connections.
“The precast system works best in straight alignment where installation is straightforward. In areas with curvatures or irregular layouts, on-site construction is best to ensure proper connection and flow,” another official explained.
