Europe's largest artificial lake district evolves currently in the former central German mining district and the Lusatia region in Eastern Germany, where more than 30 former open-pit coal mines are being flooded. By abandoning coal mining, these regions need to be restored in terms of landscape and also economy. In this regard, the lakes and their shores are key components within regional development plans. Thus, issues of soil mechanics (bank and slope stability), water quality, wave climate as well as long-term shore development are of great importance. Since investments and projects (e.g. floating houses, marinas etc.) at the lake shores strongly depend on these developments, predictions regarding wave impact and sediment transport processes under extreme and long-term conditions are necessary. In this context, the paper focusses on numerical investigations using the software Delft3D for selected lakes in this region. The modelling of the heterogeneously composed shorelines of the pit lakes (overburden sections consisting of fine grained sediments and naturally composed sections) was just one of many specific aspects that had to be considered in the assessments. Due to the objectives of the "European Green Deal", more pit lakes will emerge in Europe in the near future, and thus expecting an increase in interest and importance of the addressed research topics.