Hydromorphologic survey and assessment of the lakeshore of Lake Scharmützelsee as a prerequisite for the development of a lakeshore utilization strategy

Lakeshores are ecotones between aquatic and terrestrial habitats with a high economic and socio-economic significance. For many years, lake conservation focused on biological and chemical conditions and while improvements on these fields have been achieved, the anthropogenic pressures on European lakeshores have rather increased in recent years. Against this background, the development of utilization and protection strategies for lakeshores is urgently needed. A precondition for this is a standardized survey and assessment of the hydromorphological status which is also required by the European Water Framework Directive under certain circumstances. For this thesis, the lakeshore of Lake Scharmützelsee, the largest lake in the German state of Brandenburg, was classified according to the GIS-based Hydromorphology Lake (HML) protocol of Ostendorp (2008). Since the HML protocol was at the time still in a testing phase, methodical modifications were applied and recommendations for an improvement of the protocol are given. Deviating from the HML protocol, the eulittoral zone was delineated with a constant width of five meters and the sublittoral zone according to the potential maximum water depth where the available light permits the growth of submerged macrophytes. A detailed on-site mapping and a separate assessment of linear and planar objects in the eulittoral zone enhanced the quality of the data further. For Lake Scharmützelsee, the assessment showed an expected increase in anthropogenic structural modifications from sublittoral (impact = 1.3) to eulittoral (impact = 1.7) to epilittoral (2.5). A correlation analysis between the impacts in different zones and the mapped objects was carried out and showed inter alia that the main reasons for structural deficits in the eulittoral zone are shore stabilizations and that in the presence of large piers and marinas a reinforced shore is more likely than in the presence of small piers and marinas. Further analysis showed that small marinas and piers can impair approximately 25% of the emergent reed belt area. The results qualify to designate conservation zones for continuous natural or near-natural lakeshore sections and to identify sections with a potential for restoration. The results of this thesis were already used by local authorities to design a blueprint for a lakeshore utilization strategy.