Creating spongy cities

With flooding being a global concern, from Pakistan to Bengaluru, experts are redesigning buildings, revisiting eco-friendly materials like bamboo and studying how cities can absorb excess storm water

September 23, 2022 05:40 pm | Updated October 03, 2022 04:55 pm IST

A model of a building created by Yasmeen Lari in Pakistan being featured at an exhibition in London.

A model of a building created by Yasmeen Lari in Pakistan being featured at an exhibition in London. | Photo Credit: getty images

With rains, come floods — from Pakistan to Bangladesh, northeast India to Bengaluru. Across the planet, the devastating effects of global warming and man-made disasters are pushing experts worldwide to rethink how we design buildings and plan cities. From hands-on solutions and research publications to digital technology, the porosity of the earth and permeability of cities emerge as a central concern in the response to flood mitigation.

A rain imagination: Dilip da Cunha, Landscape architect, Bengaluru and Philadelphia

Rivers have been the spines of civilisations, and consequently, we associate flooding with overflowing rivers, but Bengaluru has no major river or natural lake: its recent horrific inundation with rains shocked the nation. Rethinking flood-resistance could well begin with architect Dilip da Cunha’s call to reimagine how we understand water. The author of several books on rivers, floods and shifting landscapes, he notes how Bengaluru’s ‘lakes’ such as Ulsoor are actually rain-holding tanks made by building bunds; traditionally called kere, these manmade interventions in the Deccan’s low grounds capture rain water.

During the recent floods in Bengaluru.

During the recent floods in Bengaluru. | Photo Credit: NDRF

At an event titled ‘Bengaluru requires a rain imagination’, Da Cunha said, “Everywhere I have gone, my admiration for the Bengaluru tank system has only increased.” Co-director of the Risk and Resilience program at the Graduate School of Design, Harvard University, Da Cunha believes our solutions in India for managing water are drain-inspired. He suggests six practical ways forward. Uncover gutters: make open gutters which we need to keep clean, cultivate and make permeable. Consume the water in tanks. Reconnect storm drains to tanks. Recover low-grounds where and when possible. Dig open wells in low-grounds, and educate people about a rain imagination.

Making more soft spaces: Swati Janu, architect, Social Design Collaborative

“Strip the concrete!” is architect-activist Swati Janu’s refrain. Janu is the main force behind Social Design Collaborative, a community-driven research, design and arts practice based in Delhi. “The essential problem is too much drainage and surface run-off not allowing the water to percolate.” Janu speaks to me from Montreal, Canada, where she is attending CCA’s residency ‘How to: do no harm’. “In European cities, they have begun rethinking their plazas. While they are great for the winter, now with climate change their summers are increasingly hot, requiring less paving and more trees in these plazas.” While it’s hard to undo extensive urban development, Janu’s simple solution to reduce the negative consequences is to make more soft spaces — flagstones instead of paver blocks, retaining ground mud instead of concreted parking areas — that allow water to naturally seep into the soil.

A kutcha house.

A kutcha house. | Photo Credit: Getty Images/iStock

Janu exhorts, “Live lightly, which is how we used to traditionally live, with minimum footprint.” Yet, given the aspirational models of concrete, glass and composite materials, how can indigenous building methods be promoted? Janu says, “Not enough research has been done in traditional materials, and that is another setback. Materials like stone, bamboo and mud have long been considered kutcha while cement and brick have come to be seen as pucca. Concrete is still preferred for pucca housing. At least in rural areas, local materials and hybrid building technologies can be supported.”

Doing like Auckland: Sachin Kumar, India Office Leader, ARUP

Dedicated to sustainable development, Arup is a collective of 16,000 designers, advisors and experts working across 140 countries. Arup’s India Office leader, Sachin Kumar talks about how they look at the green and blue infrastructure — parks, gardens, ponds and lakes — which hold the key to the city’s ability to manage heavy rainfall and other impacts of climate change, such as extreme heat events.

Auckland city

Auckland city | Photo Credit: Getty Images/iStock

Arup’s new survey assessed a city’s ‘sponginess’ or natural ability to absorb rainwater by quantifying the amount of green (trees, grass), grey (building, hard surfaces), and blue (ponds, lakes), also accounting for the particular soil types with the help of Terrain, an advanced digital tool. Mark Fletcher, Arup Global Water Leader writes: Our message is simple. Cities need to be asking — ‘how spongy am I?’ Arup’s Global Sponge Cities considered seven cities in which Auckland, New Zealand, emerged on top as 35% spongy, while Mumbai came third and equal to Singapore at 30%. Sachin Kumar emphasises, “Our survey is not intended as a score card, but to show how we can use digital tools for cities such as Mumbai to help expand blue and green infrastructure.”

Every city has its unique ecosystem and terrain, and built environments must necessarily respond to these inherent patterns. Disasters propel innovation and now, it requires we reimagine water — key to sustaining life on earth.

Bamboo solutions by Yasmeen Lari: Heritage Foundation of Pakistan

Yasmeen Lahiri

Yasmeen Lahiri | Photo Credit: wiki commons

Pakistan has one of the most fragile ecosystems. After the devastating 2005 earthquake, Yasmeen Lari (81), the first female architect of Pakistan, turned from highbrow ‘star’ architecture to ‘low-cost’ ‘no-cost’ Barefoot Social Architecture. Lari’s participatory approach involving local communities in rebuilding their homes has been much lauded. Her zero-carbon shelter designs such as the ORS (one room shelter) and Lari Octa Emergency Shelters are made primarily of bamboo, and can be assembled in a few hours.

Tanks to the rescue: Madras Terrace Architects, Chennai

Madras Terrace Architects advocates Nature Based Solutions to holistically address the conservation of water to solve problems of sewage, supply and flooding. There is also the reusable aspect of water, instead of sending it into the ground. “Our waste water treatment plant uses natural methods with banana plants ensuring that water comes out clean and gets recharged,” says Sudheendra N.K. The group’s path-breaking project ‘City of 1000 Tanks’ proposes a holistic solution to the problems of floods, water scarcity and pollution by considering all inter-relationships.

The writer is a brand strategist with a background in design from SAIC and NID.

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