How urban expansion makes Delhi susceptible to flooding

Sub: Geography

Sec: Indian Physical Geography

Urban flood in Delhi NCR:

Unchecked urban expansion is a major cause of chronic urban flooding in Delhi and the NCR.
The India Meteorological Department (IMD) recorded 228.1 mm of rain in 24 hours, an 88-year high.
Delhi’s urban flooding is exacerbated by inadequate drain desilting and poor consideration of natural drainage patterns during expansion.

A rapidly growing city:

Rapid urban expansion has seen Delhi’s geographic size almost double from 1991 to 2011, with significant growth in surrounding cities like Ghaziabad, Faridabad, and Gurugram.
By 2030, Delhi is expected to become the world’s most populous city with nearly 39 million people.
Most of this expansion has occurred on the peripheries of New Delhi, with erstwhile rural areas becoming engulfed in the capital’s urban sprawl. Cities outside Delhi, but a part of the NCR — Bahadurgarh, Ghaziabad, Faridabad, Noida, and Gurugram — have also witnessed rapid urbanisation.

Topography and drainage:

Historically, Delhi’s cities and villages were built on higher ground to facilitate natural drainage.
Modern expansion has neglected this principle, resulting in high run-off and inadequate drainage systems.
Urbanisation has led to water channelisation into concretised drains, which are often used as sewage dumps.
Construction in low-lying areas and on flood plains has worsened flooding, with areas like Sarai Kale Khan experiencing intense annual flooding.

Concrete everywhere:

Concretisation has reduced rainwater absorption, leading to more surface flooding.
Floodplain encroachment occurred:
- When the British decided to build a railway line along the riverbed.
- When the Ring Road came up, again on the Yamuna floodplain.
- Flood plains near Kashmere Gate were reclaimed by the Delhi Metro for its maintenance shed.
- During the Commonwealth Games in 2010.

No ‘water masterplan’:

The lack of a “water masterplan” and consistent neglect of water as a planning resource have exacerbated the issue.
Important water bodies have been destroyed, reducing the city’s capacity to manage flooding.
Effective flood management requires stopping construction in low-lying areas, de-concretising surfaces, and maintaining proper drainage.
Setting up filtration pits in low-lying areas can help manage water flow and prevent flooding.

Source: IE