Coastal municipalities in Lithuania, Poland and Germany are supported by our project experts to find the best installation sites for floating wetlands in order to maximize nutrient removal, gain additional aesthetics benefits to boost tourism and to prevent spatial conflicts of use. Cross-border co-operation along the South Baltic Coast will allow us to test both technological and socio-economical methodologies in different environments.
First floating island will be installed in the Curonian lagoon, Darss-Zingst and Szczecin lagoon in 2018 and 2019.
Together with our cooperation partner – the Federal State Institute of Agriculture and Fishery MV – we installed the first two small floating islands in the aquaculture research station in Born at the Darss-Zingst Bodden Chain in 2018. The two floating wetlands, made out of stainless steel mesh filled with reed stems, were planted with a variety of native emergent macrophytes. In the first year we wanted to find out which plants can adapt best to the special site conditions, grow well and remove most efficiently phosphorus and nitrogen from the eutrophicated waters. The islands are installed at the outlet of the aquaculture pond (sturgeon cultivation) and we monitored the water quality as well as nutrient removal in the plant biomass.
Due to the decreasing buoyancy of the islands from last year we installed new modified islands in 2019. This year one island’s floating matrix is made out of thermowood. The other island is again made of a stainless steel mesh which is filled with dry reed stems but this time hollow stainless steel buoys enhance the buoyancy effect. This year we planted macrophytes like purple loosestrife and yellow flag, but also sedges (Carex acutiformis) and rushes (Schoenoplectus lacustris). Both islands help us to avoid plastic utilization – we will see if the buoyancy effect is efficient this year. We will continue the water monitoring and the determination of nutrients in plant biomass this year.
Another installation of a floating wetland is planned for 2020 at the Szczecin lagoon. The municpality Vogelsang-Warsin is fighting with nutrient pollution and E.coli bacteria. A flaoting macrophyte island will be installed behind their pumping station.
Curonian spit national park installed the first active barrier in the Curonian lagoon. It is a net installation located at Nida, Lithuania in a small bay between two piers. It has a length of 200 m and buoys as well as anchoring system were made especially for the project purposes. The net was planted with indigenous plants from the Curonian spit. Local plants were chosen because they might have a highest chance to adapt to the particular environmental conditions of the Curonian lagoon. For the first year reed (Phragmites) and willow (Salix) were chosen as native plants and growth as well as nutrient accumulation will be monitored by students and researchers from Klaipėda University. Another floating island with native emergent macrophytes will be installed in Juodkrantė in the upcoming spring.
The floating island in Poland will be located in a marina on Wicko Lake in Wolin National Park. It is a shallow and sheltered area where the island can in the water also over winter. The installation is planned for 2019.