Metropolitan Solutions

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A century ago, only one in seven people in the world lived in a city. Today it’s over half, and this number is expected to grow to 70% by 2050, which equates to an extra 2.5 billion city-dwellers. The ever-increasing densities of people, buildings and infrastructure mean the challenges become greater too. How do you keep cities healthy, habitable, safe and sustainable? How do you make them resistant to climate change? These are questions that we at Wageningen University & Research (WUR) are working on, and we’re looking at them from all sorts of different perspectives, from soil science to sociology, and food and climate sciences. The knowledge we’re gaining helps with the development of new technologies and strategies for ‘future-proof’ cities.

What are ‘metropolitan solutions’?

A metropolis is a large city, in the broadest sense of the word: a collection of people and their buildings and vehicles, their activities, recreation and infrastructure, as well as the air, water, soil and green areas. Many people think of mega cities like London, Delhi or Tokyo when they hear the word ‘metropolis’, but you can also see the densely-populated Netherlands, and especially its western half, as one large metropolitan region.

metropolitan solutions amsterdam

There are lots of challenges in metropolitan areas such as this. How do you provide the growing population with sustainable and healthy food, for example? How do you deal with waste, especially considering resources are also scarce? How do you protect a city from increased flooding on one hand, and against periods of sustained drought on the other? How do you ensure a sustainable energy supply? And how do you tackle issues around migration and social cohesion?

Researchers from Wageningen University & Research are working on innovative concepts and specific solutions for questions such as these. Consider sustainable food logistics, metropolitan agriculture, underground water storage and ‘climate-intelligent’ architecture and infrastructure for example – and also fruit for schools, community kitchen garden projects and green refugee camps. What’s also very important here is collaboration between all sorts of partners with governments, companies and other research institutions. And it’s worth noting that the solutions don’t just apply for the Netherlands; they’re relevant abroad, too.

Expertise: old and new topics

‘We’re very well equipped at WUR to tackle complex city issues,’ explains Marian Stuiver, one of the Metropolitan Solutions’ leaders. She highlights that Wageningen University & Research traditionally specialises in food supplies and the green living environment. ‘Not just with regards to the “technical” side, for example in food production, but also around aspects such as logistics and sustainability. And we also have lots of expertise in social and ecological subjects. How do you make sure people are more connected with each other and their environment? What effect does nature have on our health?’

WUR is also very strong in terms of economics, management and policy, according to Stuiver. ‘How do complex governance systems work? How are different roles distributed between the authorities, business world and social organisations?’ This has led to an integral approach from these various disciplines. The ‘living laboratories’ are also important here: networks of users, administrations and researchers together testing innovative ideas and concepts in real-life situations. ‘Nature, the city and agriculture have long been interconnected in the Netherlands,’ says Stuiver. ‘There have already been lots of very interesting results.’

Climate research has become much more prominent over the past two decades. And there are even newer topics too, such as circular economics (closing raw materials and energy loops – so there’s no waste, everything is reused) and ‘the Ludic city’ (a playful city – developing and implementing innovative concepts inspired by public creativity). ‘All projects are multidisciplinary,’ concludes Stuiver. ‘This has to be inherent in such a complex subject area. The result is an enormous diversity of projects, which have together delivered usable concepts.’

A changing social environment

Increasing urbanisation isn’t just changing the physical environment; the social environment is changing too. The population is growing and changing the way it’s made up. People themselves are changing, behaving differently with each other and their surroundings. They’re moving with the times and developing new preferences. So if you want to work on the cities of the future, you need to study these social aspects too, and this is what Marijke Dijkshoorn and her colleagues from the Social Sciences Group are doing under the name Urban Challenges.

Collaboration and education

But WUR isn’t working alone. Lots of the research is carried out in collaborative links. One of these is with AMS Institute: Amsterdam Institute for Advanced Metropolitan Solutions, founded by MIT, WUR and TU Delft. Amsterdam is a ‘living lab’ for these projects.

AMS Institute also attracts students, with more and more of them opting for a course or final project on Metropolitan Solutions. Together with TU Delft, another founding partner of AMS Institute, WUR has developed a massive open online course (MOOC): ‘Sustainable urban development. Discover advanced metropolitan solutions’. The MOOC went online in 2016. Afterwards a second AMS MOOC was launched, Co-creating sustainable cities. Together the MOOCs have about 30.000 subscribers at the moment.  A two-year master’s programme, which started in September 2017, has also been set up under the guidance of AMS Institute: Metropolitan Analysis, Design and Engineering (MADE). This is a joint degree from WUR and TU Delft. Students work in multidisciplinary teams on the cities of the future for their master’s.

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Urban climate

As previously stated, climate is an important topic within Metropolitan Solutions. Climate change means we have greater extremes in temperature and precipitation – and the effects of this are relatively large in the concrete world of urban areas. ‘On average, it’s a whole degree warmer in cities than in rural areas,’ explains researcher Bert Heusinkveld from the Meteorology and Air Quality group. ‘This might not sound like much, but at night in many places in the city, it can be as much as seven degrees warmer than elsewhere.’

Cities, as he emphasises, are islands of heat. This is partly because buildings and asphalt absorb relatively large amounts of heat from the sun and there’s less wind between buildings. The warmer air rises relatively quickly, and particulate matter contributes to cloud forming. Heusinkveld says, ‘All this causes changes in local weather patterns.

Urban planning

Heusinkveld is collecting data from 24 weather stations in Amsterdam together with colleagues from AMS Institute. ‘It’s completely unique, because weather stations are traditionally not in the city,’ he explains. The research is producing new knowledge about urban weather patterns, and already making weather forecasting possible at city district level, which helps people and companies prepare better for extreme weather. But the researchers want to go a step further – or rather, a step backwards in the chain: by studying which aspects of urban planning contribute to climate effects. ‘We’re looking at what influence green areas have, for instance,’ he says. ‘And at the role architecture plays, for example with the orientation of streets and buildings. Experimenting with the effects of shadows can make a huge difference in the amount of incidental sunlight.’

Energy management in cities can also contribute to the effects of heat. More intelligent architecture and insulation for houses, factories and buildings can dramatically improve the metropolitan climate – as can cleaner and more efficient engines. ‘At the same time, we’re also looking at water management,’ adds Heusinkveld. ‘How much evaporation is there in the city, and what effect does this have on the climate? How can you manage rainwater drainage more intelligently? What role do buffer zones play? If you can understand why the city is warming up, you can do something about it.’


‘When you’re dealing with metropolitan issues, climate change is something that affects pretty much everything,’ says Tim van Hattum, Green Climate Solutions programme leader for Wageningen Environmental Research. ‘Issues such as food, habitability, health and air quality, for example – as well as the city’s water management. Climate change produces extra challenges on all these fronts.’

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Lots of the research at WUR is focusing on making cities ‘climate-resistant’. ‘This fits in with the national Delta Plan on Spatial Adaptation, which was set up in 2017,’ explains Van Hattum. The urgency is gradually starting to ramp up, so it’s important to take action now. He says, ‘Future climate change needs to be taken into account anywhere where building works take place, but climate considerations still aren’t included as standard in the world of construction.’

Climate Atlas

He names an example. In the Netherlands, hundreds of thousands of new homes need to be built before 2050 to keep up with demand. ‘It’s very important to look at where we build these homes,’ says Van Hattum. ‘We need to leave enough room for water storage in cities and preserve our green areas sufficiently.’ Research at WUR, he notes, has produced a Climate Atlas: a digital tool that shows what climate change means for areas and cities in terms of flooding, drought and extreme heat, for example. ‘This Climate Atlas can serve as a basis for cities, provinces and water authorities to put climate change on the agenda,’ says Van Hattum, ‘and work on intelligent planning and solutions.’

It’s not just the country as a whole, but cities themselves that need to have green areas as well as the capacity to store water. Green areas, as Van Hattum explains, have a cushioning effect on the city climate. And water storage can help prevent flooding on one hand, and serve as a buffer during times of drought on the other. ‘This sometimes results in conflicts,’ he explains. ‘You actually want this storage facility to always be empty so that you still have maximum reception capacity, but in times of drought you need the water. We’re trying to come up with innovative solutions for this in our RichWaterWorld project by linking information from hydrological models with real measurement data from sensors and weather forecasts, for example, to be able to better anticipate weather extremes such as heavy rainfall and periods of drought. So you can empty your storage facility in time when there’s extreme rainfall on the way.’

Combining functions

A pilot project in the RichWaterWorld framework was recently completed in Park Lingezegen, a landscape park between Arnhem and Nijmegen. ‘We combined water storage in urban fringe areas with natural values and recreation,’ explains Van Hattum. ‘Water storage doesn’t need to be in a concrete block. It can work equally well in a natural marshland area where plants and animals feel at home and people can enjoy some recreation.’ This project was a collaboration between Wageningen Environmental Research, Radboud University Nijmegen and a number of companies specialising in weather forecasting, data systems, natural water treatment and energy. ‘Initial results look very promising,’ says Van Hattum. ‘We’re now looking to see, in consultation with water authorities, if we can follow it up. There, and in other places too.’

Where we have to get to, he concludes, is ‘Water Management 2.0’: an integral method for looking at an area’s water management. ‘There will always be a certain amount of unpredictability,’ says Van Hattum, ‘because a shower can unexpectedly hit five kilometres further away than you thought. And there’s always a balance between water storage capacity and stockpiling, which is what makes this topic so interesting. How can we combine maximum safety with water usage that’s as efficient as possible?’

Social-economic consequences of climate change

When we think of urban climate research, we often consider natural science questions: how much better will it be? Where is there likely to be more extreme rainfall? And how is this rain then drained away again? But the socio-economic consequences of climate change are just as important and WUR is investigating these too, because this knowledge is necessary for deciding policy, and drawing up and implementing plans.

How are house prices affected, for example, if a canal keeps running dry and starting to smell? What does it mean for people when their house regularly gets flooded? Who determines priorities in the event of a water shortage? And whose job is it to prevent these issues from becoming problems? What role can companies, governments and the public play?

This kind of research requires an interdisciplinary approach. It’s not just technical questions that need answering, but also economic, social and administrative questions. This integral approach is one of WUR’s strong points. The combination of theoretical research, modelling, observations and experiments ‘in real life’ show what challenges come into play and which solutions work best.

Learn in the interactive infographic more about challenges in cities.
Learn in the interactive infographic more about challenges in cities.

Greenery in the city

Fewer and fewer people are producing their own food, and food in the supermarkets is coming from further and further away. This distance between people and their food is contributing to unhealthy food patterns – an insight that provides leads for new initiatives, where people are actively involved in food production in the city. We call this urban agriculture. It can offer benefits on all sorts of fronts: making the city greener, people being more active, eating healthier, more contact with each other – and food no longer needs to be shipped in from far away.

But the concept of metropolitan agriculture is still so new that many questions haven’t been answered yet, and lots of assumptions have never been investigated. Scientists from WUR are changing this and researching different types of questions. Does it make any difference, for example, who rolls out these initiatives – members of the public, governments or companies? What are the environmental effects of having green areas in the city? What are the health effects, and how does the green space influence the climate in the city? Does everyone have equal access to green projects, and who benefits most from them? And to what extent are all these effects site-dependent?

Wageningen University & Research is combining research from different disciplines to answer these complex questions. The results can help create policy and set up green spaces – and stimulate people to make use of them.

City and health

Many aspects of the metropolitan environment don’t directly benefit our health. Consider pollution, noise, traffic and the stress of the 24-hour culture, for example. This is why green areas are so important in a world of steel and concrete. The presence of parks and trees makes the city much more habitable. Numerous studies at WUR have shown that people live healthier and more productive lives, and feel happier and recover from illness faster when they live in a green environment.

‘If parks can play an important role, then perhaps vegetable gardens can too,’ suggests Esther Veen from the Rural Sociology research group. ‘Gardening is a good activity in itself. You’re outside and have access to fresh fruit and vegetables. And there’s an incentive reason to do it, because gardens need a lot of looking after.’

Gardening together

As part of the Healing Gardens project, she’s investigating, together with colleagues from the Human Diet research group, the effects of collective gardening on people recovering from cancer. The fact that (ex-)cancer patients benefit from having an active lifestyle and healthy diet has already been established, Veen explains. ‘But as a sociologist, I’m interested in the added value of gardening together with others. It can for example help people who don’t talk much be a bit more open, perhaps. Talking while working on something practical together, outside in a green environment, is much more comfortable than in a discussion group.’ Healing Gardens is a project by WUR, Flevo Campus and AMS Institute.

Veen ran an initial pilot project in Almere from April to September 2017. ‘Six people took part,’ explains Veen, ‘so not enough to be able to gain any statistical data, but useful to see what works and what doesn’t in terms of the technical side of gardening and how to tackle social aspects. How do you attract interested parties? What role do volunteers play? Why do some people quit?’

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Measuring health effects

She’s currently processing the results, and then wants to set up a larger trial to be able to measure if there are any actual health effects, and to what extent this collective activity is an effective alternative to other types of contact with peers. ‘We also want to look at questions such as if it helps to have a garden next to a hospital, or not, for example. Is this most promising for people who already enjoy gardening, or can it be implemented more broadly? We still have lots of questions, but initial results are already very encouraging.’

Food supply

Take the rapid population growth in large cities, for example. It results in an ever-growing demand for food in the city, which can lead to food shortages. The scale increases, prices are put under pressure, companies get bigger and there’s more mass production. Or not…? Research shows that consumption patterns are changing. There’s an ageing population, more people are entering the social middle classes, cultural diversity is increasing, and preferences are changing: more and more people are choosing to eat more sustainably, healthily and locally.

All this together means that cities will have to explore new directions in terms of food production and consumption. They will have to find suitable combinations of small and large-scale production methods, depending on the raw materials and resources available. This is taking place on a global scale, while at the same time requiring more local customisation. And customisation isn’t possible without the background knowledge of how food systems work.

Researchers from WUR are studying the entire food chain: what are the challenges? Who has a role to play? Which customers need which products? Where can they come from? Sometimes this requires a combination of social and economic research, and that’s what Wageningen Economic Research specialises in. This institute is modelling how climate change is affecting global agriculture, and how this translates into issues such as food prices and food safety.

Food in the city

‘Food Supply in metropolitan areas is a huge logistical puzzle,’ says Arjen Spijkerman from Wageningen Environmental Research and AMS Institute. ‘A lot of the food is shipped in from elsewhere, which has all sorts of consequences for traffic and transport. There’s also the trend for buying more food online, with even more transportation as a result. All this can lead to a certain level of vulnerability in terms of food safety, and create challenges in the field of sustainability.’

Researchers from WUR are working together on all sorts of aspects of this puzzle. They’re designing more intelligent transport logistics, with shorter, more efficient chains, better use of food waste and innovative concepts for food production. Spijkerman and his colleagues are working on this within the AMS Metropolitan Food System programme, which is focusing on the food system for the metropolitan region of Amsterdam.



‘The interesting thing about the subject of food,’ explains Spijkerman, ‘is that it brings all sorts of different aspects together, such as production, logistics, food waste and health. We’re looking for synergies that can help us make the food system more sustainable in such a way that it also creates new employment and improves quality of life.’ Established cities require a different approach from growth areas, with the latter providing opportunities for experimenting in the early stages of urban planning. The Amsterdam region, for example, is expecting tens of thousands of new buildings to be built over the coming decades.

This type of planning doesn’t just involve all the technical aspects; social considerations also need to play a role. Good planning can contribute to social cohesion. ‘This makes it particularly interesting,’ says Spijkerman. He mentions a small-scale trial project in which a fermentation plant is reclaiming energy from food waste as an example. ‘You can use this energy to run a kitchen on site,’ he explains, ‘where people from the community can come together to prepare meals. And you can link this to providing information about nutrition and sustainability.’

Farmer becomes developer

Another innovative project, ‘Oosterwold in de Flevopolder’, is making land available cheaply, which people are then free to organise and cultivate as they wish on the condition that they put in their own infrastructure and utilities – and reserve half of their lot for food production. ‘So the farmer becomes a developer,’ says Spijkerman. ‘There are of course still lots of challenges: how do you organise it? Who does what? The skill is in recognising and taking advantage of opportunities, for aspects such as waste reduction, food production and employment. It’s opening up a lot of possibilities.’

Floating agriculture

‘One of the problems of the growing global population,’ says Marcel Vijn from Wageningen Plant Research, ‘is that major cities are usually situated in fertile deltas. So they’re right in the areas most suitable for farming: the expansion of cities is diminishing agricultural areas. One way of dealing with this is by cultivating food on water.’

Vijn is working on a project that was born out of a question from ‘Stichting Drijvende Eilanden’ (the Floating Islands Foundation). ‘This foundation is working on all sorts of useful applications for floating platforms,’ explains Vijn, ‘for example as a breeding island for waterfowl. It asked if these platforms could also be used to cultivate food... a typically suitable challenge for WUR.’

New materials

Together with colleagues and students, Vijn is working an all different aspects of this issue, such as: what crops are suitable for cultivation on water? ‘Vegetables like lettuce and cabbage are obvious choices,’ says Vijn. ‘But we’re also looking at possibilities for tomatoes, peas and soya, for example. Potatoes are more troublesome, because they can’t be suspended in water. We’re already finding out which are most suitable.’

The choice of materials is another aspect. Stichting Drijvende Eilanden works mainly with polystyrene foam, because it’s relatively cheap, light and sturdy. ‘People in some developing countries have been using natural materials such as reed matting and water hyacinth for hundreds if not thousands of years already,’ explains Vijn. ‘The disadvantage of these is that they can fall apart faster, so using new, more durable materials could increase the yield.’ He emphasises that there are lots of variants possible, with all sorts of different materials, with and without soil, floating on the water or suspended in immersed boxes. ‘Floating islands for food cultivation are potentially very interesting for a country like Singapore. A shortage of agricultural land means it needs to import much of its food, and prices for fresh produce are high.’

Ontwerp van een drijvende voedsel boerderij

Education and recreation

Vijn is convinced that floating agriculture can contribute to food safety in developing countries. In the Netherlands, it’s mainly about food ‘with an added experiential value’ for the time being. ‘It gets really interesting when you can link it to education,’ he says, ‘for example about sustainability and a healthy diet. You can also combine floating agriculture with recreation to make good use of sites which otherwise don’t have any function.’ Sand reclamation pits, water storage areas and bulb fields which are temporarily flooded to rid the soil of nematodes are good example of this. ‘For temporary agriculture like this,’ says Vijn, ‘you can consider using air-filled mats that you can roll up and roll out again elsewhere relatively easily. They’re all nice ideas that we’re happy to develop further.’

He enjoys working on solutions to questions posed by society to scientists;, issues on the border between agriculture and social sciences. ‘Lots of our work is done by students,’ explains Vijn. ‘They often provide a fresh way of looking at things and approach social issues in an original way, which means they sometimes find surprising solutions. And we collaborate with social partners a lot too, so it’s not just as if we’ve simply come up with something from high up in our ivory towers. No, we’re really right in the middle of society here.’


More and more people are living in cities worldwide, so these metropolitan areas are getting bigger and more complex. This requires new technologies and initiatives to guide metropolitan life along the right tracks in the long term. Researchers from Wageningen University & Research are contributing to these new solutions. Together, they’re designing cities that combine efficient use of space with more green areas, intelligent infrastructures and climate-resistant architecture. From metropolitan agriculture to flexible rainwater storage, and from climate-neutral buildings to innovative policy models: people from WUR are contributing to this together with other institutes, governments, companies and members of the public.

The topics discussed here cover just a few of the many projects currently running. Together they provide a picture of the challenges, research and possible solutions. Further information about these and the many other projects can be found on the following pages: