'Smart Water' and harbour baths: Climate change in Copenhagen

Cities are not shopping centres or architecture exhibitions, but rather places where people live. And if people no longer want to live in these places, the city dies. That’s why our primary objective in Copenhagen is ‘liveability’, a term that for us has very concrete consequences: the services provided by a city council are not only measurable in terms of economic growth, tax revenue or the number of building sites. We have very concrete guidelines on how we want to improve the lives of residents, which we measure with ‘liveability’ surveys: ‘How happy are you in your city?’ We even practise triple-entry accounting, which in addition to money also accurately covers values such as sustainable use of resources.

Water management in the age of climate change

The two biggest challenges facing cities over the next 50 years are climate change and population growth. We need to develop a way to influence these two issues – and adapt to them, which is why Copenhagen as an entire city aims to be carbon neutral by 2025. This will take more than just a few improvements here and there – it will require changes across the board. The most important CO2 factor that local politics can truly influence is transport, which is why we in Copenhagen have prioritised the bicycle. 62% of residents cycle to work or school every day, while just 9% drive.

Another example: a decision was made in Copenhagen in 2001 to revitalise the harbour area. We planned to do something spectacular to get everyone on board with this goal. We wanted to improve the water quality to the point that we’d be able to swim in our port. We now have public swimming facilities at several locations in the city harbour. But unlike in many other cities, we swim directly in the harbour water rather than in separate pools. The port area has developed into a social and cultural centre, thus boosting ‘liveability’ and increasing the value of the previously unused spaces. We now have a district there in which people enjoy living. We’re really investing in the city and that’s paying off for residents.

The same applies to our water management. We predict there will be more and more heavy precipitation events as the climate continues to change. In other words, rainfall so heavy that the sewers are no longer able to transport the water, resulting in flooding. We’ve seen the pictures from all over the world – the problems are the same everywhere. To prevent this from happening, you would have to expand the city’s entire sewer network, equipping it to accommodate larger volumes. You can imagine what that would cost. We’re trying to take a different path, which we call SMART WATER. We want to fully digitise the provision and use of water all the way to the end consumer. Rainfall radar and precipitation sensors are thus linked with a control centre, which can then automatically use the sewer network as efficiently as possible. Water flows, is stopped, diverted, and guided into overflow basins, with everything calculated using real data in real time.

On the one hand, this requires us to optimise technologies: there are 3,000 overflow and retention basins in Copenhagen, which historically were built as required and are thus constructed very differently. We’re currently in the process of developing standardised modules as prototypes. This reduces natural development costs – and, more importantly, modules like these could then also be used around the world, once they’ve proven themselves with our rainwater. On the other hand, we also need to optimise processes. For instance, we’ve thought about whether, in cases like these, we can relieve the sewers of the run-off they usually transport. The solution: from the control centre, we close off entire sewer pipes and cut off the supply of fresh water, for example, to specific residential areas. Of course, this is a major interference in residents’ lives, who as a result can no longer shower or wash. However, when you explain that it’s an emergency measure which will occur very rarely, residents are willing to accept the trade-off. How important is a temporary limitation in convenience if it actually allows a lot of money to be saved? Plants and labour account for 80% of the price of water, which is equivalent to billions that you’d otherwise simply invest in larger pipes underground. In our opinion, there are more intelligent solutions.

Climate adaptation according to plan

A decision was made for an official climate adaptation plan in 2011 and then, one year later, the heavy precipitation plan in 2012. Both plans stipulate ambitious aims for climate adaptation in urban spaces. Over the next 20 years, at least €500 million will be invested in damage prevention in the core area of the city alone. In the past, individual downpours have caused damages of up to €700 million.

Many construction projects have been implemented since the plans went into effect. Some of the technical solutions we’ve been working with have already been tested and proven their worth in practice at other locations. But we still see plenty of need for development and room for innovation. Despite the several years of experience the city and public utilities now have with the topic, Copenhagen has not yet got to the point where you could talk about ‘business as usual’. There are still plenty of open questions that require an answer: for example, regarding the cost-efficiency of decentralised rainwater solutions and the effects on water management. There are also open questions about the smart city topic: How do you reconcile digitisation and climate adaptation and which synergies are available? Which platforms, sensors and business models do we need to ensure that smart city solutions really pay off? But we also turn our attention to quite tangible things, such as testing new technical components and systems. We’re currently developing, for example, a gutter valve which can help prevent the build-up of excess pressure in sewer systems and thus flooding during heavy precipitation events.

Climate change requires global collaboration

CALL Copenhagen stands for ‘Climate Adaptation Living Lab for Greater Copenhagen’, whose founding partners are the City of Copenhagen, the Capital Region of Denmark, Greater Copenhagen Utility (HOFOR) and BIOFOS, the regional waste water companies. CALL develops, demonstrates and markets sustainable, feasible and scalable solutions for adapting to climate change. We believe in innovative, global collaboration with cities, public utilities, research institutes and companies. And of course with engineering service providers, as experts need to be able to share knowledge as much and often as possible. Particularly in the water management sector, DMT’s many years of experience and the computer models developed there are immensely valuable. Take, for example, the ‘digital twin’ principle, which allows us to generate a complete, three-dimensional image of the groundwater and surface water in a certain area. The theoretical analyses then make it possible to run through a variety of scenarios. What happens when large volumes of rainwater meet with drainpipes that are too small? Where exactly could you install overflow basins? Which route will take the water to the harbour basin the fastest? We need to consider all of these and many other questions in advance – and thus not wait for the next downpour to learn from them.

It’s important to set ambitious aims – and charge them symbolically so that everyone knows what is at stake and that success is not only measurable, but also visible for residents. In principle, the way John F. Kennedy persuaded an entire nation to get behind the goal of the moon landing: ‘We choose to go to the Moon in this decade and do the other things, not because they are easy, but because they are hard.’ And that’s exactly how we need to approach climate change.

Want to know more? Find all of our Engineering Performance stories on this and other exciting topics here.

Information, suggestions or questions to the topic? We welcome your feedback.