Gurugram’s rainwater still follows the ground beneath its concrete

Gurugram’s streets can turn into flood channels within hours of intense rain because the city sits on a natural slope that water still follows. The Aravalli foothills lie at higher elevation, while the land falls towards the north and northwest, historically carrying stormwater through seasonal channels, ponds and natural drains towards the Najafgarh system.

The elevation gap between the foothills and the Najafgarh basin is estimated at about 60 to 70 metres. But as open ground has been replaced by roads, buildings and parking surfaces, more rain becomes rapid surface runoff instead of soaking into soil or collecting in temporary storage. That leaves drains to handle a sharper, faster surge of water.

The pattern has been visible this month: 70 mm of rain prompted Gurugram’s work-from-home advisory, while rain and waterlogging have also disrupted electricity supply in parts of the city.

A GIS and SWMM-based study of eight high-runoff sub-catchments in Gurugram found that green roofs, permeable paving and rainwater storage could cut runoff volume by up to 72.31% and peak discharge by 54.05%. Separate research cited for the city found that retention ponds integrated with existing drains could reduce simulated flood volumes in regular and extreme rainfall.

The proposed shift is not to abandon drains, but to reduce the burden placed on them. It would mean protecting flood pathways and historical water bodies, restoring ponds and recharge areas, and requiring new projects to account for the runoff they create. Roads, parking areas and landscaped edges could also hold or absorb rain through bioswales, rain gardens, permeable shoulders and detention zones.

A catchment-level map of Gurugram’s drains, water bodies and natural flow paths would be the starting point for such a strategy.