Investing in climate adaptation contributes to reducing risks and the development of a liveable and attractive city. For the city of Zwolle, surrounded by water, climate change has an additional impact. To create a climate-robust city, the municipality of Zwolle in collaborations with water authority Drents Overijsselse Delta (WDODelta) has developed the Zwolle Adaptation Strategy (ZAS). During the full development process, they were supported by Royal HaskoningDHV (content) and Stadsstroom (process). The development process of the ZAS consisted of the following phases: (1) assessment of climate vulnerabilities: climate stress test, (2) risk dialogues and strategy development, and (3) implementation agenda vision 2050.

Stress tests: vulnerability assessment

The ZAS is based on the results of stress tests. The stress tests provide insight into the consequences of extreme weather such as high intensity rainfall, prolonged heat or drought and the effect of a flood inside the city. The stress tests give a clear indication of the problems and tasks needed to comprehend climate change and which parts of Zwolle are the most vulnerable.

The ‘new normal’ for 2050

The Adaptation Strategy for Zwolle encourages a new way of working, a ‘new normal’ in which climate effects are structurally and naturally considered in all activities of the municipality of Zwolle and the water authority of WDODelta. Besides, the strategy helps the municipality, residents, companies, shops, schools and healthcare institutions to work together towards a climate-proof Zwolle by 2050. The strategy consists of the following elements:

  • Spatial elaboration at urban level: where are spatial elaborations necessary?
  • The ‘new normal’ for professionals: how to make climate adaptation the goal?
  • Private action perspective: how to include the people of Zwolle?
  • Financing: spatial elaborations have costs, how to finance them?
  • Regulations: which regulations are needed?
  • Monitoring and navigation: how to head for the end goal?

Blue-green city

Working towards a liveable and attractive blue-green city is at the forefront of the ZAS. By strengthening the green infrastructure and by giving water more space in both the public and private domain, the city becomes like a huge sponge. The sponge effect can be achieved by various measures, such as green roofs, rain barrels, rain gardens and rain-resistant streets. These measures reduce the damage during heavy rainfall and increase the ability to store water for drier periods. All important infrastructure becomes connected to one large blue-green network based on three design principles. 

Blue-Green design principle Spatial scaleWho? 
 1. Sufficient urban “sponges” for detaining (using), retaining or delaying rainwater.Buildings, streets and neighbourhoods.Municipality of Zwolle together with its residents and actors.
 2. Blue-green city network on which “sponges” can drain excess water and in which discharge and storage takes place.Neighbourhoods, districts and city.Municipality of Zwolle together with water authority of WDODelta.
 3. Emergency valves for the blue-green network and overflow areas where water can temporarily go in extreme situations.
City, region and delta.City of Zwolle together with water authority of WDODelta, province of Overijssel and neighbouring municipalities.

Adaptation Strategy for Zwolle | Royal HaskoningDHV