Start Date

2018 4:20 PM

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Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Abstract

Since the EU Water Framework Directive (WFD) entered into force in 2000 also flood retention basins located in the main channel have to ensure the migration of aquatic organisms. Therefore conventional hydraulically optimized constructions have to be adjusted to meet this requirement. During the last two decades the design of the outlet structure and the configuration of the main channel itself were focused in research in Germany. The energy dissipating component is obviously in operation during flood conditions only. Due to this main function it is so far designed focusing on hydraulic standards. Complex constructions provide the ecological passage way and the energy dissipator locally separated. Various “new” constructions are developed to combine these two functions. The “depression shaped stilling basin” (DSSB) with its continuous river bed slope features the ability to combine energy dissipation and ecological passage way in one joint construction. A lack of knowledge in design standards of DSSB leads to uncertainness in planning and approval process. The scope of the research is to advance the design standards of DSSB by taking both hydraulic and ecologic requirements into account. In a first step, decisive parameters are identified. Their ranges of values are specified based on literature research. To analyze the sensitivity of these parameters, analytical calculations as well as physical and numerical models are run. The combination of parameters and the resulting dependencies lead to construction rules. This process is exemplary presented in the paper discussing the ratio between low water and flood water discharge and its influence on the lenght of the DSSB.

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May 16th, 4:20 PM

Hydraulic and Ecological Requirements for the Design of Stilling Basins at Flood Retention Basins With Ecological Passage

Since the EU Water Framework Directive (WFD) entered into force in 2000 also flood retention basins located in the main channel have to ensure the migration of aquatic organisms. Therefore conventional hydraulically optimized constructions have to be adjusted to meet this requirement. During the last two decades the design of the outlet structure and the configuration of the main channel itself were focused in research in Germany. The energy dissipating component is obviously in operation during flood conditions only. Due to this main function it is so far designed focusing on hydraulic standards. Complex constructions provide the ecological passage way and the energy dissipator locally separated. Various “new” constructions are developed to combine these two functions. The “depression shaped stilling basin” (DSSB) with its continuous river bed slope features the ability to combine energy dissipation and ecological passage way in one joint construction. A lack of knowledge in design standards of DSSB leads to uncertainness in planning and approval process. The scope of the research is to advance the design standards of DSSB by taking both hydraulic and ecologic requirements into account. In a first step, decisive parameters are identified. Their ranges of values are specified based on literature research. To analyze the sensitivity of these parameters, analytical calculations as well as physical and numerical models are run. The combination of parameters and the resulting dependencies lead to construction rules. This process is exemplary presented in the paper discussing the ratio between low water and flood water discharge and its influence on the lenght of the DSSB.