In the cities of the future, water flows everywhereTo protect our cities against future floods, we need to redefine modern urban planning and make space for water. Blue-green cities, cloudburst highways and increased cooperation across traditional fields of expertise give the best protection and well-being, according to experts.
By Kristine Barenholdt Bruun
The water levels in our cities are rising due to global climate changes. A cloudburst can have fatal consequences on vital facilities such as hospitals and infrastructure. And smaller, frequent rainstorms can ruin cellars and lead to problems with rodents, because sewer systems are not geared up to handle the extra water.
Extreme weather is here to stay, so now it's time to find new solutions together, so we can protect our cities and make them more sustainable, explains expert Christian Nyerup Nielsen, Head of Ramboll's Department for Climate Change Adaptation and Wastewater Planning:
"Climate changes are unavoidable, but that doesn't mean that we necessarily face a bleak future with fatal consequences from flooding. With the right planning and cooperation across fields of expertise, we will not only be able to protect ourselves against damage – but also see how water can be a great advantage for our cities – aesthetically, socially and health-wise.”
A blue and green urban garden
According to Ramboll experts, water should be given priority when designing our cities in the same way that we incorporate plans for road systems, and water should be channelled to branch out between buildings and residential areas. It is not just a question of creating space for water, but also using the flow to connect the urban areas in new ways, to create social coherence and better recreational areas:
"For example, one solution would be to re-create a hidden stream or excavate an existing stream in a delta formation, so that it flows through the city. In addition to being aesthetically attractive, this would create an improved eco-system, increased property prices, social cohesion and improved well-being in cities", said Christian Nyerup Nielsen.
Room for water and well-being
Denmark's currently largest climate adaptation project, the "Blue-Green Garden City" in the town of Kokkedal, north of Copenhagen, is a good example of how cities can successfully re-create a hidden stream and use rainwater to create more interaction between the city's residents, new attractive areas and more security. Rikke Hedegaard Jeppesen, architect in Ramboll and responsible for landscape-based rainwater solutions, explained:
"In cooperation with the two architect companies Scønherr and Big, we prepared a climate change adaption plan that can improve life for residents – environmentally, culturally and socially. The project is best practice for how to develop a climate adaption plan. Partly because we cross fields of expertise that traditionally are strongly divided. Landscape architects and engineers needs to be creative and technical together at the same time – not in different offices at different times – that way you will get the best solution that covers all aspects of the project”.
“From an architectural point of view, it is worth noting that there must be a visual connection between water and parks. If we instead create closed, limited parks, we divide the city – while on the other hand, water that branches out creates social and visual connections."
More bees and fewer heavy metals
The visual connection is also crucial in the Area Renewal project in the municipality Frederiksberg (next to the city of Copenhagen) around the road Nordre Fasanvej, where Ramboll experts are investigating precisely how to incorporate local deposition of rain water into an urban renewal process:
"In Frederiksberg we base our work on technical premises, but with an artistic focus that combines technique and analysis with the aesthetics. As an example we have been able to observe that with the help of few tools, we can transform the character of the city from being rear areas, to being recreational, aesthetic and sociable areas", said Rikke Hedegaard Jeppesen.
"In addition, we are focused on what type of nature that is generated within the city as a result of further planting and increasing water surfaces. As an example we are able to observe the creation of favourable conditions for bees, which contributes to a healthy and robust ecosystem, and fewer heavy metals.
A cloudburst highway right out of town
When cities get hit by cloudbursts, drastic mitigation measures and a will to rethink city planning elements are essential to avoid fatal consequences. In contrast to the growing amount of ordinary rainwater, which can be put to positive use in cities, sudden flood water from cloudbursts cannot be absorbed by a blue and green surface alone. Part of it needs to be directed out of the city before it creates any kind of damage. Christian Nyerup Nielsen explained:
"Climate adaptation should be seen as a two-stage rocket, where the blue-green cities with visible water and green areas are just the first step. The second step is more drastic: when the rainstorm comes up over a certain level, the water is no longer a positive. It's just a question of getting rid of most of it by leading it out of town in a proper way and away from vital facilities such as hospitals."
In order to succeed, this means that we should be willing to develop our cities and rethink city planning.
"The challenge of managing cloudbursts can be solved in several ways: one solution could be redirecting traffic to tunnels under ground in order to make room for streams and parks on today’s roads. In extreme cases it is also possible to close down a tunnel – or parts of it – and use the tunnel as a cloudburst highway that collects the water and directs it right out of town. It is also possible to change the slope of roads, so that water collects in the middle of the street instead of running towards overflowing sewers. Then this water can be led to the sea or stored in other places”, said Christian Nyerup Nielsen.
Rikke Hedegaard Jeppesen added:
"We believe in keeping the solutions as simple as possible. For us it is a goal in itself to try to avoid using as many pumps as possible, because they can always break down. The traditions we create in our cities needs to be sustainable hundreds of years from now".
Did we forget climate adaption after the industrialisation?
Even though it may sound like a major effort to excavate streams, directing traffic underground and lowering the water level in city lakes is not a new idea to adapt cities to nature's forces. Looking back at our history, we can see that cities have been making climate adaptations to protect against heat, rain and earthquakes for thousands of years.
“Following industrialisation, many of us forgot to focus on the forces of nature, when designing new cities and rebuilding old ones. And now we return to this way of thinking - where it is natural to plan cities to be both sustainable and flexible, in relation to climate and nature," explained Rikke Hedegaard Jeppesen.
Here are the three most important pieces of advice from Ramboll's experts on managing climate changes:
- Work across the traditional fields of expertise from the very beginning of the project in order to create the best possible solution
- Create blue-green cities with room for water and welfare, where water basins and parks are able to collect the larger rainfalls
- Establish cloudburst roads to divert the water out of the city
Visions for cities:
Rikke Hedegaard Jeppesen, Architect in Ramboll, and responsible for Landscape-based Rainwater Solutions:
"In the future, cities will be designed with water on the surface, small parks, and streams. Water will become a feature in every corner, and it is difficult to picture a city without water and green areas. Water will become a new dimension within the city – a new layer."
Christian Nyerup Nielsen, head of department in Ramboll, Climate Adjustment and Wastewater Planning:
"All cities have mapped out their high-risk zones/areas and established an emergency plan. During cloudbursts the cities will act as big machines immediately diverting the water out. Cloudburst roads are an integrated feature, and gravitational pull is used to channel the water in the right direction."
Christian Nyerup Nielsen
Global Service Line Leader, Climate Adaptation and Flood Risk Management
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