Author(s): Lisa Schulting; Florian Dossi; Wolfram Graf; Diego Tonolla
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Keywords: No Keywords
Abstract: There is evidence that, besides shear stress and flow velocity, the rapidity of flow changes (up-and downramping) during a hydropeaking event may be a decisive factor regarding the harmfulness for riverine biota. Quantification of this assumption is still lacking, therefore we present an experimental approach, addressing macroinvertebrate drift response following hydropeaking events with five different ramping velocities at three different peak discharges. Our results indicate that drift responses of macroinvertebrates strongly relate to peak discharge and corresponding flow velocities. Further, our observations indicate that low ramping velocities reduce the drift-rates when discharge-related thresholds at peak flow are exceeded. Measures addressing these key parameters, such as the construction of compensation basins are therefore expected to have strong mitigating effects.
Year: 2018