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

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.

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.

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.”