Dune oasis made from local shell sand
22.02.2023 – "Offenbach by the sea" is how a cultural initiative of the same name once ironically described the city. Of course, this was meant provocatively and was deliberately exaggerated. But a little coastal flair will soon indeed be created on Offenbach's harbor island.
Offenbach can now boast a large dune made of shell sand on its riverbank. The public utility company OPG has thus added another attraction to the park it has created at the tip of the harbor island, which is still inaccessible for the time being. The mound of sand in the middle of the 10,000 square meter park is littered with small river mussels. From the hill, the view extends far to the west as far as the Frankfurt skyline and to the east over the entire harbor district. "Even if we unfortunately have to wait a considerable time until the final completion: One of the most beautiful urban green spaces will be created here, which will offer near-natural recreation in a unique waterfront location. It is therefore good that things are at least moving forward and that a first special feature has now been integrated into the park," says Lord Mayor Dr. Felix Schwenke.
2,500 tons of the finest shell sand were supplied by the Frankfurt construction materials recycling and logistics company Blasius Schuster KG for OPG Offenbacher Projektentwicklungsgesellschaft mbH. The sand was dredged from the Main by the company Hülskens Wasserbau and transported to Offenbach harbor on a crane ship and pontoon. There, the material was transferred directly from the ship to land.
The shell sand came from a maintenance measure on the Main waterway at the Opelhafen in Rüsselsheim. The natural drift of sand and gravel had restricted the navigation channel in places. Before the material could be dredged to remove the shallows, divers first took soil samples of the drifted sand. Analysis of the composition confirmed that the sediment was safe to use for the "Park in den Dünen" on Offenbach's harbor island from an environmental point of view.
"We were quickly convinced by Blasius Schuster's offer, because it means we can use local materials from the region for our dune oasis in the interests of sustainability," says Daniela Matha. She is Managing Director of the municipal utility company OPG, which is developing the former Offenbach industrial port into a lively mixed quarter with living, working, education and local recreation for its sister company Mainviertel GmbH & Co.
The sustainable recycling of mineral materials is the focus of the Blasius Schuster Group, which was founded 76 years ago. It is one of Germany's leading environmental service providers and specializes in the recycling of mineral building materials. "The company intends to move into the ROCKYWOOD office building ensemble in Offenbach harbor with a team of construction and recycling specialists. Under the direction of Blasius Schuster, a hub for the circular economy of mineral building materials is being created here, in which environmental engineers, laboratories, construction, technology and processing companies are also involved. It is important for Offenbach that the port now also functions as a business location," emphasizes Mayor Schwenke. The ROCKYWOOD project is currently being built using a timber hybrid construction method and is also committed to the concept of sustainability.
Blasius Schuster Managing Director Daniel Imhäuser: "We want to reuse construction waste in the best possible way and shift truck transportation from the road to environmentally friendly modes of transport. We therefore move our bulk goods on almost a thousand trains and barges every year." For example, when transporting shell sand by ship from Rüsselsheim to Offenbach, around 100 truckloads of heavy 40-ton trucks could have been avoided. Regional reuse is also environmentally friendly and sustainable. The need for the "Park in den Dünen" was a stroke of luck, as there are only limited uses for shell sand; it is unsuitable as a building material for concrete production, for example.
OPG began creating the island park in 2020. The public green space at the tip of the island for all Offenbach residents was very important to local politicians from the outset. It is located in an exposed waterfront location in the far west of the new harbor district between the banks of the Main and the harbor basin. According to the plans of the Henning Larsen office and in coordination with the city's Urban Design and Greenery Department, the park with a dune oasis, a riverside boulevard and a picnic meadow will offer people attractive local recreation and provide a new habitat for birds and other animals with vegetation appropriate to the location, including a bee pasture with wild herbs.
The park is still in the first stage of development. The site has been modeled and planted with trees and shrubs, which are now growing. Paths have been laid out, cables installed and the boat promenade along the harbor basin has been extended into the park area. However, the green area is still not safe for traffic, the final layers of paving and paths are missing, and there are no safety railings at the tip of the island, benches or park lighting.
"Unfortunately, we are dependent on the neighboring buildings for the completion and opening of the facility," says Daniela Matha. However, the investor has not yet submitted a building application for the planned high-rise buildings. "Nevertheless, we are thinking about an interim use. We may be able to open the fenced-off Inselpark in 2024, at least temporarily, and make it accessible at set times."