From sponge cities in China to ‘berms with benefits’ in New Jersey and floating container classrooms in the slums of Dhaka, a range of projects are looking to treat storm water as a resource rather than a hazard

This article titled “What would an entirely flood-proof city look like?” was written by Sophie Knight, for theguardian.com on Monday 25th September 2017 06.30 UTC

They call it “pave, pipe, and pump”: the mentality that has dominated urban development for over a century.

Along with the explosion of the motorcar in the early 20th century came paved surfaces. Rainwater – instead of being sucked up by plants, evaporating, or filtering through the ground back to rivers and lakes – was suddenly forced to slide over pavements and roads into drains, pipes and sewers.

Their maximum capacities are based on scenarios such as 10-year storms. And once they clog, the water – with nowhere else to go – simply rises.

The reality of climate change and more frequent and intense downpours has exposed the hubris of this approach. As the recent floods from Bangladesh to Texas show, it’s not just the unprecedented magnitude of storms that can cause disaster: it’s urbanisation.

The downtown Houston skyline and flooded Highway 288 following Hurricane Harvey in late August 2017. Photograph: Thomas B Shea/AFP/Getty Images

Paul Morris checks on neighbours’ homes in a flooded district of Orange, Texas, following the devastation of Hurricane Harvey. Photograph: Spencer Platt/Getty Images

Floodwaters from the Addicks Reservoir inundating a Houston neighbourhood in the aftermath of Hurricane Harvey. Photograph: Brett Coomer/AP

Postal worker Lonzell Rector makes his rounds among flood damaged debris from homes that lines the street in the aftermath of Hurricane Harvey in Houston. Photograph: Matt Rourke/AP

  • Hurricane Harvey displaced more than one million people, resulted in at least 44 deaths and damaged 185,000 homes in Houston alone

The US National Weather Service said the “breadth and intensity” of the rainfall that came with Hurricane Harvey in late August was “catastrophic”, and “beyond anything experienced before” – the city was overwhelmed with devastating speed, as can happen in areas where much of the land is paved.

A recent survey of global city authorities carried out by the environmental non-profit CDP found 103 cities were at serious risk of flooding.

With climate change both a reality and threat, many architects and urbanists are pushing creative initiatives for cities that treat stormwater as a resource, rather than a hazard.

The two-mile Pilsen Sustainable Street, commissioned by the Chicago Department of Transportation to improve the urban ecosystem. Photograph: Urban Labs

Permeable pavements: Chicago’s ‘green alleys’

One city already preparing for a climate future – or present – is Chicago, parts of which saw almost 20cm of rain in four days this July. It is projected to have 40% more winter precipitation by the end of this century.

The city has poured significant investment into reimagining stormwater management over the last decade, including building more than 100 “Green Alleys” – permeable pavement that allows stormwater to filter through and drain into the ground – built since 2006.

This article titled “What would an entirely flood-proof city look like?” was written by Sophie Knight, for theguardian.com on Monday 25th September 2017 06.30 UTC

They call it “pave, pipe, and pump”: the mentality that has dominated urban development for over a century.

Along with the explosion of the motorcar in the early 20th century came paved surfaces. Rainwater – instead of being sucked up by plants, evaporating, or filtering through the ground back to rivers and lakes – was suddenly forced to slide over pavements and roads into drains, pipes and sewers.