Expansion of the Main embankment in the city center begins: preparatory work starts with tree felling
10.11.2025 – From Monday, November 17, preparatory work will begin in the city center for the final section of the dyke extension, which will increase the protection of Offenbach residents against future flooding. In order for the main work to start in late spring 2026, around 190 trees will have to be felled, including around 120 on the dyke crown path.
It is not possible to preserve all of the trees on the dyke due to the extensive construction work involving the installation of sheet piles and structures for anchoring back, as this means massive interference with the root area. Many of the trees will also be felled in the area in front of the Main to the east of Friedhofstrasse because, in addition to installing the sheet piling, more retention area for water from the Main (retention area) must also be created here.
"This step is extremely difficult for us. These trees are very dear to us Offenbach residents, they provide shade and characterize the familiar cityscape along the 1.8-kilometre section of the dyke. We took a close look at every single tree as part of the construction planning and carried out lengthy checks to see whether felling could somehow be avoided. This cost us a lot of time and delayed the project, but it was worth it. Unfortunately, we cannot avoid this drastic cut," explains Paul-Gerhard Weiß, the department head responsible for planning and construction.
"As we will be ensuring flood protection in future via a steel wall in front of the dyke, I am pleased that we will be able to plant even more trees on the dyke after the construction work than before. But yes: it will look really bad at first and we will need patience until the trees reach their full size. Nevertheless, we must not forget: The safety of citizens from future flood hazards must have top priority and unfortunately the current trees have to go," Weiß continues.
The felling work has been coordinated with the Office for the Environment and Climate. They will be carried out outside the breeding and settling season for birds and other animals and will take around three weeks. For motorists on Mainstrasse, the work will again mean restrictions, but only in sections and temporarily. The carriageway will be narrowed to one lane at the height of the work. A full closure is not necessary.
Main work to start in spring 2026
When the main work on the dyke begins in late spring 2026, however, considerable obstructions are to be expected. Mainstrasse will then gradually become a major construction site for around two and a half years. "The dyke expansion is a long-standing project and will once again demand strong nerves from citizens. But in view of the increasing risk of flooding due to climate change, the expansion is urgently needed," emphasizes Weiß. The traffic regulations for the major project are currently still being coordinated. There are currently no plans to close Mainstrasse completely. "It is very important to us that traffic can flow, as the road is an important main artery, especially for the citizens of Bürgel and Rumpenheim. Nevertheless, everyone must be prepared for significant obstructions with an impact on the entire inner city area. It is expected that only one lane will be available in large sections. Cycle traffic will also be taken into account in the construction logistics, with the aim of keeping disruption to a minimum. We will announce all the details in good time," explains Weiß.
The expansion of the Main embankment in the city center is the latest major project to strengthen flood protection in Offenbach. Many years ago, the state of Hesse upgraded the section of dyke it owns in the Bürgel district and in large parts of Rumpenheim. The sections in Rumpenheim, which are the responsibility of the City of Offenbach, were completed at the end of 2024. The Office for Planning and Construction is in charge of planning and implementation.
Background
The total costs of the flood protection project approved by the city councillors in 2019 have since risen to 38.5 million euros. The state of Hesse is currently funding the implementation with 13 million euros. The project costs have risen sharply since the Darmstadt Regional Council's planning approval decision. In addition to the generally sharp rise in construction costs, this is due to extensive rescheduling in order to preserve some of the trees and reduce the impact on traffic and the pipeline network below Mainstrasse during the construction work. The city has therefore already applied to the state for an increase in funding.
The planning for the dyke extension was prompted by an expert opinion from the state, according to which the Offenbach Main dyke is not high enough to withstand future floods, which statistically can occur every 200 years. This corresponds to a requirement imposed on the city of Offenbach by the regional council of the state. "This means we are well prepared for future floods. This is of existential importance for all people living in the city center in order to protect their belongings, but also their own lives," explains Weiß. As the owner, the city of Offenbach is obliged to maintain the dyke and is responsible for its upkeep, renovation and expansion. The dyke sections under the jurisdiction of the City of Offenbach have a total length of around 2.6 kilometers. It is 1,866 meters from the Carl Ulrich Bridge to the city centre area, 548 meters from Rumpenheim to the Schlosspark and the remaining166 meters to the Mühlheim border.
In 2011, there was intensive public participation, during which numerous suggestions and wishes were incorporated into the planning. "We are using the construction project to improve the opportunities for recreation and quality of stay for walkers, cyclists and families. The implementation on the Main dyke combines flood protection and quality of stay," says Weiß.