Author(s): M. Oertel; G. Heinz; A. Schlenkhoff
Linked Author(s): Mario Oertel, Andreas Schlenkhoff, Heinz G. Stefan
Keywords: No Keywords
Abstract: Since there is a new European Water Framework Directive (EU-WFD) all mainly anthropogenic modified waterbodies have to be transformed into nature-orientated conditions. Weirs, bank mounts, stream straightenings and river mouths must be analyzed in detail to determine possible rehabilitation measures. A state of the art solution to re-nature large water surface steps (such in case of weirs e. g. ) is the arrangement of so called rough ramps and slides. With these it is possible to conquer mainly slopes of the river bed by arranging several natural obstacles (large stones). The result is a close to nature solution, also with climb possibilities for fishes. Rough ramps and slides have a various discharge potential. Low discharges can flow between the arranged stones, so they act like simple obstacles with form losses. With increasing discharges some of the stones may be overflowed and weir equations become necessary. In case of totally flooded ramps and slides other approaches are needed. Now the system is close to a general channel flow with a complex implementation of a generalized river bed roughness (e. g. Darcy friction factors). To analyze various effects on the water surface level, the flow velocities as well as on resistant coefficients of the arranged boulders a physical model is built up at the University of Wuppertal’s Hydraulic Laboratory. State of the art measurement techniques give information about main flow characteristics as well as forces on the boulders. The physical model allows variations of boulder arrangements and discharges. All model runs are compared with numerical 3-D simulations using the CFD software FLOW-3D.
Year: 2010