Improving adaptation capacity of built infrastructure in urban areas

The Municipality is in an area which is seven metres below sea level and is highly vulnerable to water-related risks from the sea, rivers, rainfall, and ground water. The municipality works extensively on flood adapted buildings, urban water management, dyke reinforcement, disaster preparation, floating amenities and water capture. It also has responsibilities over local policies related to urban water management, climate change adaptation (National Climate Stress Tests), and spatial planning, with strong links to water and flood risk management organisations in the region, as well as links to universities.

In this pilot, the Municipality of Capelle aan den Ijssel is looking for workable flooding solutions that foster long-term resilience in our region. Through prioritising higher involvement of stakeholders and residents in the process, the Cappelle pilot will produce and test an implementation pathway for a ‘Climate Street’. The problems in Capelle aan den IJssel are complex:

• The soil is like a sponge and subsides, so needs to be raised every 10-30 years
• Soil is heavier than the layers underneath, so using it simply speeds up the compaction process; the more soil is added, the heavier the top layer becomes and the more often it requires raising again.
• The area is below sea level, and the ground water needs to be high in order to combat subsidence. This is a challenge since the area is also prone to heat stress and drought.
• During heavy rain, water needs to be held in the area so it does not all go to the drainage/outlet pool (boezem) at once. This is difficult to manage with the ground water level just 50cm below the surface.

To combat the twin problem of flooding and subsidence, we are piloting the installation of innovative Bufferblocks beneath the soil to hold water and reduce subsidence. They are easy and cost-effective to install and maintain, and we expect them to perform better than sand and lightweight materials over time, making them cheaper per year than traditional solutions.

To gain public support for the Climate Street, we involved residents in every step of the decision-making process via public information campaigns, consultations, and workshops to explain the rationale behind using the Bufferblocks. We developed a communications tool that has now become part of the wider Muicipality’s communications strategy and the pilot has become a leading example for how to engage residents in adaptation action in their neighbourhoods.

For more information on the use of Bufferblocks in Capelle aan den Ijssel, visit bufferblock.nl.