Why is Chennai flooded every year?

Why is Chennai facing water-logging issues? Which factors have contributed to the disaster? What can we do as architects and planners to prevent such calamities? Let's unpack it all.

Image Credit: Illustration by Sambhavi Thakur via Newslaundry

Tamil Nadu lies on the coast of Bay of Bengal which is infamous for cyclones, depressions & heavy monsoon rains. This volatile ocean belt, with its frequent extreme weather events, is a major contributor to Tamil Nadu's flood woes.

Recently, Cyclone Michaung rained down on the city brutally. More than 400 mm of rainfall, in 3 days.

Reclaimed land and clogged storm water drains worsened the situation. Let me explain. Chennai’s natural ecosystem has 3 rivers – the Kosathalaiyar, Cooum and Adyar – and the manmade Buckingham Canal.

With the city expanding, its water bodies – ponds, lakes, canals, streams and marshlands– were drained and concreted for construction. Imagine so much of water pouring down, having nowhere to go.

A study by IIT Madras claims that 2 decades ago, Chennai region had 650 water bodies. Now only a fraction of them is left. This encroachment of wetlands and water bodies has costed the city heftily, yet again.

Trash, including plastic and construction waste, continuously being dumped in the storm water drains, caused blockages which did not help with water logging.

What can we do?

As architects and planners, we can play our part in building a more resilient future. Disaster mitigation is to be kept in mind on all levels - from macro to micro.

Here are mitigation measures for planners and architects -

Town Planners:

Land-use planning and hazard mapping can go hand in hand. What are they you, ask? Hazard mapping is creating maps that identify and illustrate potential hazards in a specific area. These maps have info about risks such as natural disasters (like floods or hurricanes) and human-made hazards (such as pollution). They draw data from satellites and other scientific studies.

Land-use planning is basically deciding which land-use (like residential, commercial, industrial etc.) will be in which part of the city. Combining hazard mapping with this will ensure that sensitive land-uses like residential can be placed away from flood prone areas.

Proper land use planning combined with the right infrastructure is what our cities need. The great storm surge barrier located near Rotterdam is an example of good anti-flood infrastructure. It is a massive, movable barrier that can be closed to protect the city from high water levels.

Image Credit: The great storm surge barrier Via Amusingplanet

Go Green: As a town planner, green spaces are your best friends. Green spaces with their grass, and trees and plants have soil. Which is a permeable surface that allows rainwater to soak into the ground. Such green zones are a savior as they stop water logging.

One of the biggest contributors to Chennai floods was lack of permeable surfaces - with the lakes, the marshlands, and soil gone, all the rainwater had nowhere to go. Going green can save cities.

In New Orleans, USA - After Hurricane Katrina, the city adopted a comprehensive land use plan that designates certain areas as “green zones” and prohibits development in high-risk flood areas.

Architects: Design for Resilience

Elevate structures above flood levels - Stilts work wonders.

Incorporate flood-resistant materials - Bricks, concrete and other materials, strong enough to withstand floodwaters.

Design for easy evacuation - Clear exits, simple layout, emergency info displayed, sturdy structure, you know the drill.

Netherlands has gone one step further and have created floating houses built on a platform that can move up with water levels and go back to normal when flooding goes down.

Image Credit: via The National

Chennai's flooding is a wake-up call for planners and architects.

Chennai's floods highlight the importance of designing cities with disaster mitigation in mind. From hazard mapping to incorporating green spaces, town planners can make informed decisions about land use. Architects can design buildings that are elevated, use flood-resistant materials, and prioritize easy evacuation. By working together, we can build cities that are resilient to extreme weather events.

You can read more about planning resilient cities here . If you're an architect or designer looking to expand your knowledge and skills in the field, consider exploring the workshops offered by Kaarwan.

Our result-oriented workshops are designed to help professionals like you achieve your career goals through affordable and practical skill-based learning.