Concrete or sponge? Dubai’s post-flooding options

Reuters/Rula Rouhana

• ‘Sponge cities’ can ease flooding
• Experts encourage green solutions
• Landscaping can absorb water

In the wake of last week’s floods, retrofitting Dubai with traditional, concrete-based drainage systems would be expensive, time-consuming and complicated.

As an alternative, authorities should look to nature-based solutions, industry professionals told AGBI.

“Dubai should not repeat the mistakes that have been made in most of the Western world,” said Ronny Berndtsson, professor in water resources engineering and deputy director of the Centre for Advanced Middle Eastern Studies at Lund University in Sweden. 

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“New infrastructure should be based on nature-based solutions such as wetlands, green roofs and water gardens.” 

Dubai and other parts of the UAE are still reeling from the heaviest downpour in 75 years, which last Tuesday dumped more rain in one day than the country typically gets in a year.

Dubai’s Crown Prince Sheikh Hamdan bin Mohammed bin Rashid Al Maktoum instructed developers yesterday to pay for the temporary relocation of affected residents and for the subsequent clean-up. 

This follows UAE President Sheikh Mohamed bin Zayed Al Nahyan’s order last week to investigate infrastructure resilience nationwide.

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Quashing rumours that cloud-seeding might have contributed to the deluge, local authorities and weather experts pointed the finger at climate change, which is believed to be making rare, extreme events more common. 

There are, however, “low-hanging fruits” that should be addressed and would be less costly, said Karim Elgendy, associate director at Buro Happold and associate fellow at Chatham House. 

Elgendy cited the use of landscaping to transform a city into something of a sponge, capable of naturally absorbing excess rainwater. 

“The permeability issue is probably the quickest thing that they can deal with,” Elgendy said. “The places that flooded, the roads and the runways for example, have nothing but concrete, so the water has nowhere to go.”

Public spaces, like children’s playgrounds, could instead be envisioned as both residential amenities and buffer zones, according to Elgendy. 

“There are some good examples around the world where parks… designed entirely for neighbourhood leisure would in an hour’s notice become completely submerged in water if the water goes too high in other places,” he said. 

The concept of “sponge cities” originated in China, where it remains more widely adopted, but there have been efforts recently to introduce it to the Middle East.

Open rainwater ditches rather than traditional pipes, permeable road asphalts and parking pavements, wetlands and rain gardens can also help mitigate the impact of heavy rainfall, added Berndtsson.

“Of course, you need to adapt the nature-based solutions to the local conditions,” he noted. “So in Dubai maybe green roofs might not be that suitable.”

Cities with arid, desert climates should also equip at least new buildings with technology that can harvest rainwater to flush toilets and other domestic uses, said Berndtsson.