Urban Flooding: A Crisis Of Climate Change, Urban Planning, And Outdated Drainage Systems

In recent years, Mumbai, Chennai, Bengaluru, and Hyderabad have experienced severe floods, highlighting the vulnerabilities of urban infrastructure in extreme weather events.

Mumbai, India’s financial capital, is a prime example, where monsoon rains routinely turn roads into rivers, bringing the city to a standstill.

The 2020 deluge, compounded by a high tide that prevented water from draining into the sea, left vast areas of the city submerged. 

Similarly, the Chennai floods in 2015, caused by the heaviest rainfall in over a century, led to over 500 deaths and displaced thousands.

Bengaluru, once known as the city of lakes, saw flooding in 2022, submerging tech parks, housing societies, and roads, highlighting the vulnerability of even the most developed urban areas.

For the National Disaster Management Authority (NDMA), which initially focused on riverine floods in rural areas, urban floods were not always a priority. After the catastrophic 2005 Mumbai floods, triggered by an unprecedented cloudburst, the NDMA had to rethink its approach and began to treat urban floods as a distinct disaster.

The NDMA has since developed a comprehensive National Disaster Management Framework that highlights the interconnectedness of the economy, environment, and development.

It emphasises disaster mitigation and preparedness, particularly for urban areas that are increasingly at risk due to rapid urbanisation and climate change.

Common Threads Across Indian Cities

Urban flooding is caused by natural and man-made factors. Mumbai's chronic flooding is a result of ongoing land reclamation and urbanisation, that has choked natural waterways and hampered the monsoon drainage system.

A crucial drainage component, the Mithi River is heavily encroached upon and clogged with waste, the once-extensive mangroves along the river have largely disappeared.

Chennai's floods are due to rapid urbanisation which has eaten into natural water bodies and wetlands. Poor drainage infrastructure and water mismanagement, compounded by climate change, have led to erratic weather patterns and intense rainfall.

Bengaluru has seen rapid urbanisation leading to encroachment and construction over many of its lakes and stormwater drains. 

Poor maintenance of existing stormwater drains, along with rampant unauthorised construction, has added to the city's flooding issues. Hyderabad faces annual flooding due to a combination of heavy monsoon rains and uncontrolled urbanisation.

The increase in impervious surfaces has led to higher runoff, overwhelming the stormwater drainage system. Poor stormwater management, including inadequate desilting of drains, further hampers the city's ability to manage even moderate rainfall.

Despite their unique challenges, several common factors contribute to urban flooding across India. These include rapid urbanisation leading to the loss of natural water bodies, poor maintenance of drainage infrastructure, encroachment on floodplains and wetlands, and the impact of climate change.

The combination of these factors creates a perfect storm for urban flooding, leaving cities vulnerable to even moderate rainfall events.

Experts Sound Alarm, Call for Action and Innovation

Urban planning experts and environmentalists have long raised concerns about the escalating impact of unchecked urbanisation and climate change on Indian cities. 

Dr RK Bhat, a prominent environmentalist, underscores the gravity of the situation, pointing out, "Indian cities are facing a dual crisis of climate change and poor urban planning. The destruction of natural water bodies and wetlands for construction purposes has removed the natural buffers that once protected cities from flooding." 

This sentiment is echoed across the expert community, highlighting a growing consensus on the urgency of the issue.

Dr Anjal Prakash, Research Director at the Bharti Institute of Public Policy, says urban flooding is no longer just a seasonal issue but a chronic problem driven by climate change.

"The intensity and frequency of rainfall events have increased, but our cities haven't adapted their infrastructure to cope with these new extremes", he notes.

Anjali Verma, an urban planner, brings attention to the infrastructural deficiencies - "Most drainage systems in Indian cities were built during the colonial era and were designed for much smaller populations. With urbanisation, the population has exploded, but the infrastructure has not kept pace". 

The lack of integrated urban planning is a critical factor behind these issues, with Prakash warning that unplanned construction on floodplains and the transformation of wetlands into real estate have compromised natural drainage systems. 

Agreed Himanshu Thakkar, Coordinator at the South Asia Network on Dams, Rivers and People, "Encroachment on lakes and rivers is a major contributor to urban flooding. These water bodies act as natural buffers, absorbing excess rainwater. When they’re built over, the water has nowhere to go, resulting in floods."

Experts like Dr Radhika Khosla advocate the adoption of green infrastructure in response to these challenges.

She suggests incorporating elements such as permeable pavements, green roofs, and urban wetlands can significantly mitigate the impact of urban flooding by mimicking natural processes to manage stormwater more effectively.

However, addressing urban flooding is also a governance issue. Dr Shashi Shekhar, former Secretary of the Ministry of Water Resources, stresses the need for better policy implementation and coordination among various governmental bodies.

"We need stricter enforcement of environmental regulations and better coordination between municipal, state, and national bodies to implement flood mitigation measures effectively," he argues, underlining the importance of governance in tackling this multifaceted crisis.

The interplay of climate change, urbanisation, and governance creates a complex and urgent challenge for Indian cities, demanding a holistic approach that combines technical innovation with effective policy implementation.

Combating Urban Flooding 

Stopping flooding in urban areas would need a multifaceted approach that combines climate resilience, sustainable urban planning, and modernised infrastructure.

Key recommendations include restoration of natural water bodies, upgrading drainage infrastructure, implementing sustainable urban planning, developing climate action plans, and raising public awareness.

Restoring and preserving natural water bodies such as lakes, wetlands, and rivers is critical, as these ecosystems act as natural buffers against flooding and help in groundwater recharge.

Indian cities also need a massive overhaul of their drainage systems, including separating stormwater drains from sewage systems and building new infrastructure capable of handling the increased volume of water brought on by climate change. 

Urban planning must incorporate the creation of green spaces, permeable surfaces, and rainwater harvesting systems to manage runoff effectively.

Cities should develop and implement climate action plans that address the risks posed by extreme weather events, build flood defences, create early warning systems, and ensure urban development aligns with climate projections.

Public awareness and community involvement are also crucial, as communities must be involved in decision-making processes and in the maintenance of local infrastructure to ensure long-term resilience.

By restoring natural water bodies, upgrading infrastructure, and implementing sustainable urban planning practices, India can build more resilient cities capable of withstanding the challenges posed by a changing climate.

As the central government envisions regional development and growth in smaller towns through its vision documents and budgets, it is crucial to plan supporting infrastructure, particularly drainage, with careful consideration of regional hydrology, contours, and climatic zones.

This approach is essential for ensuring a sustainable urban future, securing both water resources and protecting against flooding.