Delhi adopts new precast technology to upgrade drainage network

New Delhi: Delhi govt has rolled out a new construction method for stormwater drains in the capital, under which it would be using precast drain boxes instead of the conventional cast in-situ technique, officials said.The move is part of a citywide drain remodelling programme aligned with the drainage master plan. “Around 20 tenders have been issued so far with work under way in Shalimar Bagh. The project will be expanded to other areas in a phased manner,” said PWD minister Parvesh Verma.The shift to precast technology is aimed at enhancing structural durability, speeding up execution and reducing pollution at construction sites.

Unlike the in-situ method, where materials such as cement, sand and aggregates are mixed and poured, on-site precast drain boxes are manufactured in factories under controlled conditions and installed at the location.Verma said the key benefits include consistent quality and faster completion timelines. “Since the components are made off-site, installation is quicker and causes less disruption to traffic and daily life,” he said.

Officials added that precast drains come with around 50-year warranty, making them more durable than conventional systems. The approach also helps cut down dust and air pollution generated during on-site construction, especially in densely populated areas.“We are focusing on construction methods that are efficient, long-lasting and less intrusive. Precast systems allow us to maintain quality standards while also reducing environmental impact,” he said.However, officials clarified that a complete shift is not being implemented. Instead, a hybrid model is being followed to suit different site conditions. Precast boxes are being used in stretches with straight alignments, while the in-situ method continues in areas with curves or complex junctions.“The precast system is ideal for straight sections where installation is relatively simple. For bends and irregular layouts, the flexibility of in-situ construction is still required to ensure proper connectivity,” an official said.Another advantage of the precast method is the shorter duration of excavation.“Traditional construction often leaves stretches dug up for days due to curing time, whereas precast components can be installed quickly, reducing the period for which roads remain blocked,” said Verma.