Dry retention reservoirs with the special management regime, so-called flood polders, mitigate the floods by accumulating the river overflows. The current process of succession and overgrowing by woody vegetation is accompanied with the spread of ruderal and alien invasive species. These changes and consequent processes are undesirable regarding the biodiversity conservation, landscape ecological function and water retention capacity point of view. Because we know the causes and consequent processes, we could design the management practices to achieve a favorable status of the area.