Lösungsstrategien für die Sedimentationsproblematik an der Wahnbachtalsperre

摘要

The predam of the Wahnbach reservoir is impaired in its function to hinder solids entering the main reservoir due to sedimentation. In order to solve the problem, five solution approaches were developed and compared with regard to ecological and economic consequences. These approaches were excavation (dry or wet) in combination with either dewatering in flushing fields, geotextile tubes or mechanical systems and continuous sediment transfer. Except for the transfer, all approaches intend to remove the morphologically important sediment permanently from the watercourse system. In addition to unfavourable erosion phenomena in the lower river reaches, these solutions are also economically disadvantageous as the material usually has to be disposed of. During a continuous transfer, the solids are not removed from the flowing water system but added to the downstream system in near-natural concentrations. Since overloading of the underwater is prevented, the sediment promotes the development of morphologically and ecologically valuable structures. At the same time, further handling of the solids is no longer necessary. In consequence, the continuous sediment transfer is not only the most economical but also the most ecological alternative of the investigated approaches.