Donau-Ybbs - Donau- Ybbs Linkage
The project aimed to restore the natural dynamics of the River Danube and its most important tributaries in the Lower Austrian Alpine foothills. The project succeeded in reconnecting many fish species with their natural spawning grounds and in providing important new spawning grounds for endangered fish species at the mouth of the Ybbs. The area also shows signs of becoming a valuable breeding site for wetland birds. The fish bypass was constructed as similar to a natural channel as possible. The bed was sealed with clay and enhanced using pebbles, rocks and wood. An innovative water-supply technique provides a normal flow of 1.500 l/s and ensures a minimum of 700 l/s using a vertical slot and pumps in case of water shortage in the Danube. Monitoring revealed that fish were able to use the bypass in a natural way to swim around the section of river affected by the power station. To restore the mouth of the river Ybbs, the project purchased 3.8 ha of private agricultural land, excavated 80.000 m3 of earth and relocated 800 m of cycle path. Once water was allowed to flow into the redeveloped area, natural forces took over the shaping of the channels and banks. Monitoring showed that the new mouth of the Ybbs has already turned into a nursery for common Danube fish and highly protected species.