Climate-proofing coastal cities against rising sea levels and floods
Devastating hurricanes in Texas and Puerto Rico, wild typhoons in southern China, the worst monsoon floods in years in India and Bangladesh: will it get worse? The bad news is that it will. Extreme weather is expected to intensify and become more commonplace in the coming years. At the same time, sea levels will continue to rise.
All of this will dramatically affect the vast majority of the world’s cities. So can anything be done? Yes! The good news is that many cities have already begun to take action, cleverly combining common sense and high technology to protect their people and places. Join URBAN HUB as we visit some of them.
Published on 01.03.2018
What’s going on?
Climate change is real. Global warming caused by human activity is melting polar ice. This puts more water into the world’s oceans – raising the sea levels – and disrupts the climate patterns to which we’ve grown accustomed. But that’s only part of the problem.
As cities have grown, much of the land needed for filtering water through the ground and back to rivers, lakes, and seas has instead been filled in and built upon. Paved roads have forced rainwater to drains and sewers, which fill up and clog in extreme situations. Over time, this lack of sustainable city planning has created an untenable situation.
What can be done? Examples of cities doing something
Many cities have started to experiment with solutions, testing new technologies and providing inspiration and workable examples for other cities. One of those is the American city Chicago, Illinois. The main issue for Chicago is rain and snow. The city is expected to receive up to 40% more of it by 2100.
One solution being tested: permeable pavement. Rain and melt-water soak into porous rock, where embedded microbes remove pollutants. The clean water is then channeled to nearby plants or back into Lake Michigan and 80% of precipitation is diverted from the city’s sewer system. The most ambitious of these “green alleys” so far is a 3.2 km stretch.
Sponge cities in China
In China, the government has ambitiously launched the design and construction of sixteen “sponge cities.” The new center for Changde (population 1.3 million) will incorporate canal-lined streets – “eco-boulevards” – that allow floodwater to flow naturally through the city without disrupting everyday life. High-density buildings will be concentrated on slightly elevated land in this low-lying river basin. The strategy is to work with nature, not against it.
The Climate Proof Program in Rotterdam
Located on the North Sea, some parts of Rotterdam, Netherlands, are nearly 7m below sea level. The city already has an impressive system of dikes as well as the gargantuan Maeslantkering storm-surge barrier. City officials have now embarked on a multi-year mega project that incorporates the strengthening of these “hard” solutions.
But the Rotterdam Climate Proof Program also includes a comprehensive series of new “soft” measures, such as protecting vital wetlands and planting more plants and trees. Water plazas are another measure that temporarily collect storm-water runoff from the nearby built environment. The Benthemplein water plaza, for example, is able to store 1,800 m3 of water.
The Maeslantkering has two Eiffel Tower-sized arms that close to protect the city of Rotterdam from surging seas. Watch how the huge storm barrier works in this 20-second, time-lapse video.
Coastal corridors around New York City
2012’s Hurricane Sandy was a wake-up call for New York City and the entire northeastern United States. Destructive and deadly, it was also the third costliest hurricane in US history. Partly as a result, a proposal currently being considered would take the eco-boulevard to the next level and establish “coastal corridors” throughout the entire region.
The plan allows for low-lying land to remain or revert to a quasi-natural state in a series of green strips stretching from inland to the coast. Buildings on higher ground and existing urban neighborhoods would be “densified.” The result would be contiguous corridors that alternate between those for natural water management and those for buildings and roads.
Multipurpose mega project in Singapore
The city-state of Singapore is protecting its city center from monsoons and rising sea levels with the Marina Barrage and Reservoir. This mega infrastructure project stabilizes the tidal flux, improves drainage, and reduces the flood-prone area of this low-lying city. It could serve as an inspiration to other low-lying cities like Jakarta.
The project also incorporated a system for more effective rainwater collection that now provides 10% of Singapore’s fresh water needs. Not only that, but the Marina also provides new space for parks, outdoor recreation, and tourism – further enhancing the city’s quality of life.
More cities take up the challenge
There are many more examples of how cities are creatively dealing with rising waters.
Here are a few of them:
- In Dhaka, Bangladesh, solar-powered shipping containers are being repurposed to house vital municipal services. They use recycled plastic bottles to float above any flood.
- DaNang, Vietnam, has a flood-resistant housing program that offers lines of credit and loans for poorer families to renovate their homes to withstand flooding or build homes that will.
- Surat, India, has instituted a state-of-the-art early warning system to alert inhabitants to impending floods, thus avoiding panic as people move to higher ground.
This beautifully animated, short video from the OECD (Organization for Economic Cooperation and Development) shows what a number of other cities such as Copenhagen, Yokohama, Toronto, and Sydney are doing to adapt to climate change.
Seeing urban climate-proofing as an opportunity
We see many examples of cities creatively deploying technology to better face flooding. But that’s not all: investment in these mega infrastructure projects also can be good for nearby wildlife and the environment, as well as providing additional urban beauty and recreational opportunities for residents.
Employment also gets a boost. After all, infrastructure doesn’t build itself. If we act now, we will be able to climate-proof our cities well. We will also create a “ripple effect” of other real benefits that together will make our cities better than ever.
What steps is your city taking to climate-proof your future?