Rapid flood protection for the municipality of Dielsdorf

Following a comprehensive incident analysis, 11 sub-projects were identified that needed to be implemented quickly to protect the village and its population. In various places, the stream beds were too small and too narrow. As there is little open space in the settlement area and some streams are very steep, the channels could not simply be widened. Instead, so-called step-pool systems and rough-bed channels were planned. While in stepped basin systems the beds and steps alternate, in a rough-bed channel large stones with smaller and larger joints are laid throughout the entire stream bed. This allows the flow velocity of the water to be significantly reduced, even on short, steep stretches, without impairing the ability of fish to ascend.

Two of the eleven sub-projects were aimed at optimizing surface runoff. Existing earth dams for collecting and channeling water were upgraded and raised. An agricultural buffer zone of around ten meters was defined above them to prevent them from being eroded by intensive use in the future. In addition, three new intake structures were planned and terrain and road adjustments were made.