Urban Expansion Increases Delhi’s Flood Risk

Context

Delhi, one of the world’s fastest-growing cities, has seen its geographic size nearly double from 1991 to 2011. This rapid urban expansion has come at a cost, making the city increasingly susceptible to flooding during the monsoon season. The principal reason behind chronic urban flooding in Delhi is unchecked and ill-thought-out urban expansion, which has paid little heed to the city’s natural topography and drainage patterns.

Topography and Drainage

• Tughlakabad, Shahjahanabad and other historical cities of Delhi, were selected and had been built on higher grounds to drain out the rainwater. If one were to examine New Delhi’s villages then the centre would consistently be at a higher level compared to the outskirts for the same reason. However, as the city has grown over the years, the thought process hasn’t been really focused with regards to construction together with the capability of the land regarding drainage.
• In addition with high intensity rainfall, there is a lot of run-off and hitherto inadequate drainage facilities have been furnished. The relief goes from the Ridge to the river which is rather steep – 100 metres are dropped. However, because of crude urbanisation, water cannot just flow in this gradient because the majority of it is patronising the concretized drains that have become sewage bins.

Concretization and Encroachment

• Their construction in the regions that are borderline and flood plains has only worsened the situation. Several drains from various areas in South Delhi discharge their wastes at Sarai Kale Khan,a very swampy area in South East Delhi near Yamuna. 
• Infrastructure development in the areas of Delhi that are part of the floodplain started much earlier with the construction of the rail line laid down by the British in the 1900s. Many years later, the Ring Road was proposed, built also on the Yamuna flood plain. Through the years, the floodplain has been employed in every which way; it has been used to erect bridges, buildings and what have you.
• Overall about 65 hectares of floodplain areas in Kashmere gate were appropriated for the construction of the maintenance shed of Delhi Metro. Subsequently, in 2010 during the Commonwealth Games, a bus maintenance facility was developed on approximately 25 hectares of area of the floodplains. Especially the ITO-Pragati Maidan region that was flooded for years was earlier a low-lying water area.

Inadequate Drainage Infrastructure

Factors such as inadequate desilting of drains by civic authorities also play a part in the city’s flooding woes. The final risk susceptibility map revealed that the north and northwestern part of North Delhi are at very high risk of waterlogging.

The recent deluge in Delhi has uncovered the flaws in urban planning, posing environmental and inclusivity concerns. Inadequate drainage infrastructure and the lack of a comprehensive water management plan have exacerbated the problem.

Measures to Improve Flood Resilience

To upscale Delhi’s flood resilience, a multi-pronged approach is needed:

• Restoring natural drainage systems: Reviving and maintaining natural drainage channels, such as the Barapullah nullah, can help improve water flow and reduce flooding.
• Improving drainage infrastructure: Upgrading and regularly maintaining the city’s drainage network, including desilting of drains, is crucial.
• Regulating construction in flood-prone areas: Strict enforcement of building codes and regulations to prevent encroachment on flood plains and low-lying areas.
• Promoting sustainable urban design: Incorporating green infrastructure, such as permeable surfaces and green spaces, can help reduce run-off and improve water absorption.
• Developing a comprehensive water management plan: A holistic approach to water management, including rainwater harvesting, groundwater recharge, and wastewater treatment, can help build resilience against flooding.

Conclusion

Delhi’s susceptibility to flooding is a direct consequence of unchecked urban expansion that has disregarded the city’s natural topography and drainage patterns. Concretization, encroachment on flood plains, and inadequate drainage infrastructure have exacerbated the problem. To build a more resilient Delhi, a combination of restoring natural drainage systems, improving drainage infrastructure, regulating construction in flood-prone areas, promoting sustainable urban design, and developing a comprehensive water management plan is necessary. Only by addressing these issues can Delhi mitigate the impact of urban flooding and ensure the safety and well-being of its residents.

Source: The Indian Express

UPSC Prelims Practice Question

Q. Which of the following factors has contributed most to making Delhi more prone to flooding due to urban expansion?

a) Inadequate desilting of drains by civic authorities

b) Increased rainfall intensity due to climate change

c) Concretization and encroachment on flood plains and natural drainage channels

d) Lack of a comprehensive water management plan for the city

Ans – “c”

Explanation:

According to the search results, the principal reason behind chronic urban flooding in Delhi is unchecked and ill-thought-out urban expansion, which has paid little heed to the city’s natural topography and drainage patterns.

The key factors contributing to Delhi’s increased flood risk include:

• Concretization and construction in low-lying areas and flood plains, which has reduced the ability of rainwater to percolate into the soil and flow through natural drainage channels.
• Encroachment on flood plains and natural drainage systems like nullahs and wetlands, leaving little room for water to flow.

While other factors like inadequate drain desilting, climate change, and lack of a comprehensive water management plan also play a role, the search results highlight concretization and encroachment as the primary drivers of increased urban flooding in Delhi due to rapid and unplanned expansion.

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