Jannemarie de Jonge is a member of the Dutch Board of Government Advisors, which organised knowledge sessions about planning based on the water and soil system in regions such as Zwolle/Kampen/Dalfsen and the Arnhem/Nijmegen green metropolitan region. ‘We designed a national ecological network in the Netherlands in the 1990s that was based on the soil and water system. But it hardly played any role in terms of urbanisation. So I was pleased with the Parliamentary Letter on Water and Soil as Leading Factors,’ says De Jonge. ‘Vital soils and living water are needed for biodiversity but that awareness is still in the early stages, certainly in cities.’

The Board of Government Advisors wants to change this and it has already launched a number of campaigns, such as contests about bio-based and nature-inclusive building and an overview of good examples of projects in the field of water and soil as leading factors. ‘We also published a booklet in which we explain that, as a region, you must first map out the soil and water system and the climate effects. That provides you with a picture of what it is better to do, and what not. Take agriculture in peatlands, for example. All kinds of solutions have been devised here with innovative drainage to keep the soil wet. But if you know there won’t be enough fresh water in the long run to keep the system going, you’re investing in something that won’t work in the future. We look forward to helping municipal authorities with the implementation of this phased plan.’

The Board established a knowledge coalition and, working with the Ministry of Infrastructure and Water Management and Deltares among others, guided four regional authorities during a number of sessions. ‘You really look at things in depth. Each area has its own focus.

With the Leiden/The Hague/Delft region, we looked at the regional level from the perspective of a neighbourhood, and then you realise that every drop counts. That drop falls somewhere in the city and will eventually pass through the drainage system on its way to the sea. When you have peak rainfall, with a lot of drops, the system gets overloaded, with flooding as a result. You want water to slow down and stay in the soil longer, and so every pavement tile gets in the way of infiltration.

You can come up with solutions by taking a more fundamental look at how to use that space better. On the university campus in Delft, for example, a lot of room is still taken up by paved car parks. If you tackle that, you can prevent nuisance flooding further downstream in the system in The Hague.’

The benefit of a knowledge coalition of this kind under the banner of the Board of Government Advisors is the independence. ‘In many area processes, the focus soon turns to different interests and negotiations about what can or cannot be done; this process is about properly understanding how a particular area is structured and what the challenges are. We are not a threat. And that’s why we work so pleasantly with Deltares, who provide independent knowledge and reflection. We still need to learn so much more about the soil. What does vital soil look like, which soil functions are important, how will climate change have an impact? This is still a blind spot for many people. If you see a tree that is twenty metres tall, you need to realise that – roots and all – it goes down twenty metres below the ground.’

Amsterdam is responding to national and international developments in the domain of sustainable land use and management. Those developments include the Parliamentary Letter on Water and Soil as Leading Factors, and the European soil strategy and monitoring directive. ‘In addition, we also work primarily on the basis of our own ambitions in the areas of greening, climate adaptation, restoring biodiversity, and liveability, which come together in Amsterdam’s Environmental Vision,’ says Thijs Vlaar, policy consultant for the City of Amsterdam. ‘We drew up a definition of soil health in which we set out what we expect from the soil in specific locations. Agreeing on that definition gives us a yardstick we can fall back on.’

In collaboration with the Wageningen University and Research Centre, Amsterdam is developing a soil health index. ‘That is an instrument that allows us to assess the value for soil use at specific locations. During area development, we can identify at an early stage which types of soil are involved and how the soil is performing. And so we can, for example, avoid building a park in a place where the soil is absolutely unsuitable. Individual soils involve different nuances in terms of use and structure.’

The index also makes it possible to assess soil problems in the city. ‘We can see what role the soil plays and which indicators are involved.’ The Healthy Soil Strategy Memorandum has now been drafted. It describes how Amsterdam will implement its own ambitions relating to soil, and to the relevant national and European developments.

That also involves challenges for how we use soil and water, Rozendaal says. ‘In the past, we often had room left in the town for new buildings, but that’s a thing of the past now. Any building plans we have involve dilemmas. If we want more housing, there also has to be room for green areas to enhance biodiversity.’

At present, the municipal authority is working on the further elaboration of the Environmental Vision, which also includes the ‘Spatial Assessment Framework for a Climate-Adaptive Built Environment’, the first national elaboration of the principle of water and soil as leading factors. It provides the municipality with a picture of where they can build by showing the risks for each location in terms of flood risk management, problems with excessive rainfall, land subsidence and drinking water.

The municipality wants to engage in dialogue with the local people. ‘We have set up a participation process,’ says Rozendaal. ‘Can the new building be a little higher and what kind of green facilities are needed? That’s what we want to hear from our residents and, in this way, we also hope to raise public awareness.’