The Marielyst area on the southern part of Falster Island is developed partly on land reclaimed in the nineteenth century, mainly for agriculture and recreational purposes (summer housing).
The area is facing saltwater intrusion problems both from the sea and fossil marine waters in the deeper part of the exploited (confined) fractured chalk aquifer. Saltwater intrusion occurs due to drainage pumping and abstractions for water supply and irrigation (especially during summer), and is expected to increase further due to climate change and sea level rise.
In an ongoing study, initial assessments have been made on the potentials of SWS to control saltwater intrusion and to reduce risks of flooding from drainage canals, and eutrophication of coastal waters of the Baltic Sea around the Island. Potentially, the injection of treated water from the drainage canals into the underlying confined chalk aquifer may mitigate not only saltwater intrusion but may also reduce flooding and eutrophication risks. The latter is a severe problem for the ecological status of the Baltic Sea and many other coastal areas globally and techniques to reduce nutrient loadings from agriculture and sewage systems is currently evaluated in a large research program for the Baltic Sea in the Soils2Sea project.
SWS market replications at Falter Island will demonstrate the ability of SWS to control saltwater intrusion and reduce flooding and eutrophication risks. This shows the flexibility of SWS, being adaptive to the local environment and able to solve multiple water resources / quality issues in an integrative way. Moreover, the Falster Island replication allows for testing of SWS in a hydrogeological setting (fractured chalk aquifer) for which SWS have not been validated before.