DENIL - Hydraulic measurements and analyzes of a modified DENIL fishway at variable endowment for the Bautype trout region

The EU Water Framework Directive defines binding environmental targets for the Austrian waters. A major contribution to the achievement of environmental goals is provided by the Fish passes. Through these structures, fish can ascend to the upper reaches to deregulate there and to multiply. Many of the native fish species are threatened or endangered. So far, the construction of fish ladders or fish harbors has been associated with enormous costs. The DENIL fish pass is an extremely area - and cost - efficient fish migration aid that has been used for more than 100 years. In Austria this corresponds Fish ladder not the state of the art, as it was previously only efficient for large fish. For small fish it is classified as not functional. In recent years, a modification of this fish ladder was worked on and the structural details adapted. The construction of a pilot plant for the adapted fishway has also shown remarkable results, which are unique to DENIL fish passes. In order to optimize the technical arrangement of the fishway, measurements on model arrangements are required. Through the measurements made in the course of the project on adapted model arrangements, connections between design changes and the hydraulic conditions in the traveling corridor can be worked out. These can be transferred to the prototype and supported by biologic sampling (counting of ascents). For this purpose, the prototype is adapted structurally according to the results obtained, fish caught in a trap are counted, and the fish data are compared with those before the conversion.