Hydromorfologisk regim för Ålands kustvatten och sjöar

Sammanfattning: Physical pressure caused by human activity is a significant and growing environmental problem that has a major impact on aquatic environments and habitats. To deal with this problem, the EU Water Framework Directive demands that hydromorphological status assessment of surface waters be implemented by all member states as part of the ecological status assessment. The aim of this thesis was to develop a method for assessing the hydromorphological status in lakes and coastal waters of Åland in accordance with the WFD guidelines, and to perform the status assessment of two water bodies according to the developed method.  An evaluation manual based on three quality factors – connectivity, hydrological regime and morphological conditions – and associated parameters was developed from a combination of WFD parameters, Swedish and Finnish assessment criteria and custom solutions. The assessment parameters were adapted to local conditions as well as available data and the assessment was conducted using GIS to ensure consistent and time-efficient execution. In accordance with the developed manual, the assessment was carried out for the coastal water body, Västra Hamnen, and Lake Långsjön. Lake Långsjön received a hydromorphological status of “good”, the primary pressure being a small regulation dam adjacent to the water body. As expected, Västra Hamnen showed a greater physical impact due to hydrodynamic effects caused by ship traffic and a road embankment, as well as a greater morphological impact due to artificial shoreline and land use in the surrounding area. As a result, Västra Hamnen received a hydromorphological status of “unsatisfactory”. The results of the project show that an assessment of the hydromorphological status of the surface waters of Åland is not only possible with the data currently available, but can be conducted in a resource and time efficient way using GIS and will facilitate the assessment of all of Åland’s lakes and coastal waters according to WFD guidelines. This report will: form the basis for reporting to the EU; account for both the methodology that will be used for hydromorphological status assessment on Åland and for the outcome of the assessment of the selected water bodies; and provide guidance for the further assessment of hydromorphological status. The method used has a promising future in development and extension opportunities as new research becomes available, and will put Åland at the forefront of hydromorphological assessment in Europe.