Two green space restoration projects in the Mainz city area are upcoming or have just begun. First, the removal of pavement in the Kaiserstraße/Boppstraße sidewalk areas (approximately 135 square meters of new green space) has been underway since yesterday, Thursday, October 22, in the first section of Kaiserstraße where the asphalt has been cut. This will be followed by the Schönbornstraße/Holzhofstraße area (approximately 63 square meters of new green space). 

The large sidewalk area at the intersection of Kaiserstraße and Boppstraße, which was created after the turning lane was relocated, will be partially unpaved and upgraded. Many factors had to be taken into account in advance—such as fire department access routes, utility lines, path connections, and historic preservation. The new landscaping will feature a tree, individual shrubs, and a planting of perennials.

At the intersection of Schönbornstraße and Holzhofstraße, construction is scheduled to begin on Wednesday, November 4, 2026. Here, the existing tree pits will be combined into larger green spaces and planted with ground-covering shrubs and perennials.

In addition, the removal of impervious surfaces along the sidewalk at Altenauergasse/Hintere Christofsgasse (approximately 48 square meters of new green space) has already been commissioned. This work is scheduled to begin in mid-November following various preliminary studies.

Climate adaptation is a central task of municipal public services—and the removal of impervious surfaces in the highly densified inner-city area is an important component of this effort.

A set of initial unsealing measures was developed by a working group of several experts within the administration and is now to be implemented in stages. These include the unsealing projects 

• Kaiserstraße at the corner of Boppstraße, 
• Holzhofstraße at the corner of Schönbornstraße, 
• Altenauergasse, 
• Reichklarastraße at the corner of Flachsmarktstraße, 
• Balthasar-Maler-Platz,
• Neubrunnenstraße, and 
• Barbarossaring.

Further measures are in the planning stages and are expected to follow. 

“Land Availability”—Not Every Desired Area Can Be Unsealed 

Project selection is based on the urgency of local climatic conditions (“heat islands”) as well as the local shortage of green space. In addition, the size of the potential area to be unsealed is a decisive factor, ensuring that the construction effort and the resulting benefits are in a reasonable balance. 

One challenge in land unsealing is the availability of land. Many sealed, seemingly suitable areas are ruled out because other land uses conflict with the project or because important considerations are involved that preclude it —in this context, many issues and constraints must be taken into account, such as access routes for fire and emergency services, existing underground cables, pipes, and sewers, events, transportation routes, and historic preservation…

For the reasons described above, creating green spaces is generally easier to implement than planting trees. At the same time, the coordination effort required for all measures is high.

Since municipal budget funds are also limited, funding is increasingly being sought for this segment. For initial measures, funds from the federal NKK program (“Natural Climate Protection in Municipalities”) have been committed, covering 80% of the costs. The total cost of the first land-unsealing projects is approximately 950,000 EUR. Funding of approximately 500,000 EUR has been committed for these projects. 

Janina Steinkrüger, Commissioner for Environment and Mobility, said: “I am delighted that we can now announce the launch of the first land-unsealing projects in the city, which sends an important signal regarding climate adaptation. Every step taken within the urban fabric helps us move forward. I would like to extend a special thank you to the highly dedicated team at the Land-Unsealing Working Group, whose commitment and ideas are making these projects possible.”