Re-engineering Cities for Flood Resilience

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By Peter Madden – Chief Executive of Forum for the Future.

In the last couple of years, communities across the world have experienced devastating floods. As the threat of flooding becomes even more severe in future decades, how will we re-engineer our towns and cities to be resilient?

We will see huge steel gates that automatically rise up from the earth to block floodwaters. River-mouth barrages, many kilometres long, will hold back storm surges, while giant self-inflating bags, that mould themselves to contours, will seal off tunnels and underground railways from encroaching water.

Many people will live in houses that, quite literally, float up as the water rises, trailing flexible cables and pipes. These will keep the occupants and their possessions dry, and then return to their original position as floodwaters subside.

Recent floods – from Ohio to Venice, Argentina and the Philippines – have brought enormous financial costs and human misery. According to the Environment Agency, floods are now the number one natural hazard facing the UK. And the risks will get worse, both here and overseas.

Throughout human history, we have built our major settlements on low-lying land near rivers and harbours. Climate change is already bringing sea level rises, and more severe weather events, threatening these settlements.

Population growth and continuing urbanisation will increase the number of people at risk from flooding; while deforestation, intensive farming and concreting over ever-more land mean there’s less natural drainage for heavy rain and bursting rivers.

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The world is going to have to adapt. Important infrastructure will have to be placed more intelligently in flood risk areas. Computer servers, switching-gear and back-up generators can no longer live in basements. Electricity substations and water treatment plants will have to be lifted out of danger zones.

Utilities will begin to invest in micro-grids, limiting electricity outages, water contamination or broadband disruption to smaller areas. Planning laws and building regulations, across the world, will increasingly require such design changes.

This will mean that, as well as cultivating their land for crops, farmers will be encouraged – or paid – to plant trees and dig ponds that slow down, store and soak up water. Natural defences, such as salt marshes, will provide wildlife havens as well as acting as giant sponges. And in cities, new parks and playing fields will provide civic amenity for most of the year – and a harmless place for water during floods.

All this will mean finding money to pay for improved protection and resilience. There may be some low-hanging fruit (the odd tweak to design specs when swapping-out existing infrastructure), and there’ll also be win-wins with ecosystem enhancement. Some defence costs will be paid for by concerned individuals and localities.

Ultimately, though, the big schemes will require investment from public authorities. Given the value of urban land and the costs of economic disruption and human misery, it will be money well spent, and the sooner the better.

In coming years, we can look forward to a host of smart flood protection technologies and solutions. Among them, the cleverest will be the systemic ones: those that, rather than trying to hold back the rising tides, reassess our relationship to water in the first place.

This article originally appeared in Green Futures, the magazine of independent sustainability experts Forum for the Future. Images via Torcello Trio and Stevep2008

  • Maria Josep Ripoll Berenguer

    I agree. I am from the mediterranean basin and we are used to floods. The first steep is to change our relationship to water bodies and to the land we inhabit.