I M M E R S E IMplementing MEasuRes for Sustainable Estuaries T R A N S N A T I O N A L C O N F E R E N C E E X C H A N G E R E P O R T L A B 12 - 13 June 2019 Gothenburg, Sweden T R A N S N A T I O N A L E X C H A N G E L A B # I M M E R S E On 12-13 June 2019, over 60 participants estuaries joined the first IMMERSE Transnational Scheldt (NL/BE), Elbe (DE) Exchange Lab (TEL) in Gothenburg, Sweden. 7 HuIsefjord/Holbaekfjord and Together, they discussed a range of estuary- Roskildefjord (DK), Göta älv related topics and participated in four (SE) and Tees and Humber (UK) interactive workshops on sediment management; governance; and flood partners protection. The IMMERSE Transnational Lead partner: Flanders Exchange Labs provide a platform to share 11 Department of Mobility and practices and progress on the development Public Works (MOW) of solutions for estuarine management issues. The purpose is to advance years development and transfer of solutions IMMERSE will run from across those involved in estuary 3 October 2018 until September management in the North Sea Region. This 2021 report presents a summary of the discussions: more information can be found in the presentations that are available for download on the IMMERSE website. 1 FOR MORE INFORMATION: NORTHSEAREGION.EU/IMMERSE | SOCIAL: @IMMERSE_NSR T R A N S N A T I O N A L E X C H A N G E L A B # I M M E R S E P L E N A R Y S E S S I O N Frederik Roose from the Flemish Department of Mobility and Public Works (IMMERSE Lead Partner) kicked off the TEL with a presentation to introduce the IMMERSE project. With a budget of €3.7m (50% ERDF co-financing) and a project period from October 2018 to September 2021, the IMMERSE partnership is made up of 11 partners from 6 different countries across the North Sea Region. The partners,including both direct estuary managers and related knowledge institutes, focus on management issues; developing and implementing measures; and stakeholder engagement. The key objective of IMMERSE is to improve the design, testing and implementation of estuary management measures by using transnational knowledge and stimulating stakeholder integration, which is where the Transnational Exchange Labs fit in. The communication objectives of IMMERSE are approached in line with the stakeholder involvement objectives, making use of existing networking groups, organizing the TELs and developing stories about IMMERSE activities and concrete examples of estuary management across the North Sea. In order to set the scene and to share with participants the story of the region in which they would spend the two days, Håkan Alexandersson from the Regional Authority of Vastra Götaland gave a presentation on the ‘Regulation of Lake Vänern, a challenge for the Göta River and Gothenburg’. As in most parts of the world, the water level in the Göta Älv is rising, making the design and implementation of flood protection measures of great urgency. Lake Vänern is Sweden and the EU’s largest lake, with a catchment area constituting around 10% of the total surface area of Sweden. With 93 kilometres, the Göta Älv is Sweden’s longest watercourse. It is a complex system with major risks and difficult consequences. The Swedish Geotechnical Institute is developing a plan for continuous stability improvement along the river, while at the same time the Port of Gothenburg is being expanded in order to become the first port in the new era of Arctic navigation. 2 T R A N S N A T I O N A L E X C H A N G E L A B # I M M E R S E P L E N A R Y S E S S I O N In 2026, dredging will intensify, new locks will be installed and the quay and turning basin will be widened, in order to increase the capacity of the port to receive ocean-going vessels. This will have environmental impacts, affecting the flow of the river and the salt water wedge. The current regulation strategy secures against flooding, but contributes to overgrowing of nature on the banks of the river, threatening natural interests. With a plethora of stakeholders including 18 municipalities, 15000 landowners and the fisheries, shipping, agriculture, industry, tourism and water conservation associations and little coordination between them, the time is right for the establishment of a safe and environmentally adapted regulation strategy for lake Vänern, taking into account both natural values as well as societal interests. Closing the first plenary session, Nikol Nielsen Gulis from the Port of Gothenburg gave an ‘Introduction to sediment management activities in the Port of Gothenburg’. The port needs to be dredged every four to five years, and 75% of the sediment is classified as contaminated. Since the 1960s, the contaminated sediments, coming mainly from old shipyards that are heavily contaminated with TBT, are stored in a closed part of the port. However, this is now a protected area for birds. The strategy for the future is to instead use the dredged sediment to build land fields with the use of the S/S method. The challenges to do so include the fact that the main pollutant is TBT, and the long process of obtaining environmental permits. At the same time, it is certain that the construction of new locks in the Port of Gothenburg will impact the sediment management, but what this will look like exactly is still not known. 2 T R A N S N A T I O N A L E X C H A N G E L A B # I M M E R S E S E D I M E N T M A N A G E M E N T I : P O R T O F G O T H E N B U R G Introduction The first interactive session focused on sediment management in the Port of Gothenburg and discussed the development of innovative methods for treating and re-using contaminated sediment. The session was moderated by Anna Wilhelmsson and Ann-Margret Strömvall from COWI and the Chalmers University of Technology. Chalmers University (IMMERSE partner) and local institutions are developing methods to treat and re-use contaminated sediments from the Port of Gothenburg. The session introduced the sediment stabilization pilot in the Port of Gothenburg as well as a similar case from the Scheldt estuary in Belgium. Eduardo Epifano from the Port of Gothenburg introduced the expansion of Nya Arendal. In order to increase capacity and to cope with future freight volumes, the port needs to be dredged every four to five years and the contaminated sediments need to be handled appropriately. To this end, a new terminal is now being constructed in Arendal by stabilizing and solidifying contaminated dredged masses with cement and ground granulated blast-furnace slag (GGBS) or oil share fly ash. This treated sediment will serve as the base of the future RoRo and container vessel terminal which will take up a space of 22 hectares. To prevent the release of contaminated particles to sea, geotextile will be placed on the embankments and water from the stabilisation process will be of a lowered pH value through the use of carbon dioxide. The main contaminant in the sediment is TBT, but PAH, PCB and other heavy metals are also found in the sediment of the port. Since TBT is influenced by the pH level the most and as it can be locked up in a stabilized form, this is the focus of the port expansion sediment treatment process. 2 T R A N S N A T I O N A L E X C H A N G E L A B # I M M E R S E S E D I M E N T M A N A G E M E N T I : P O R T O F G O T H E N B U R G Per Lindh from the Swedish Transport Administration and Kristina Bernstén from COWI informed session participants about the stabilization of TBT polluted sediments with a particular focus on technology and environment. By using innovative stabilization and solidification methods, contaminated sediments can be used in construction. A field test was performed in the Port of Gothenburg in 2017, in a new port area called Nya Arendal. The results show good geotechnical properties, with high shear strength and low permeability. The environmental properties also show good results. During the filling phase, special consideration needs to be given to turbidity and TBT in the displaced water, as high pH will increase the leaching of TBT. In addition, it is often difficult but even more so important to design for the differences between lab tests and the actual pilot plant. Patrick Van Goethem from the Flemish Department of Mobility and Public Works presented the TBT treatment methods from the AMORAS treatment plan in the Port of Antwerp. The dredged sediment here consists mainly of sludge or sand and is treated differently depending on the sediment grain size and level of contamination. Following some recent modifications, AMORAS, the sludge processing plant in the Port of Antwerp, can now accept TBT-contaminated sludge by adding an additional treatment step with activated carbon filters and sand filter systems. The first preliminary results indicate that this has been effective in order to prevent TBT to re-enter the water in the harbour after TBT-contaminated sludge has been presented at AMORAS.