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Gewählte Publikation:

Aigner, J; Kreisler, A; Rindler, R; Hauer, C; Habersack, H.
(2017): Bedload pulses in a hydropower affected alpine gravel bed river
GEOMORPHOLOGY. 2017; 291: 116-127. FullText FullText_BOKU

Abstract:
This study investigated the sediment resupply and transport dynamics at the Upper Drau River upstream of Lienz (Eastern Tyrol, Austria). Due to a hydropower plant, a 24 km long river reach of this alpine gravel bed river is under residual flow conditions, although sediment is still resupplied into the reach through many active torrents and tributaries. As a result, sediment deposition in the residual flow reach intensified, hence increasing maintenance efforts to stabilize this river section and ensure flood protection. In combination with a new sediment management program,,a continuous bedload monitoring system was installed 2 km downstream of the residual reach in 2001 to support the development of adapted sediment management strategies. The surrogate bedload monitoring system consists of 16 impact plate geophones, installed over a 17 m wide cross section. The unprecedented 15-year dataset of high-resolution bedload intensity revealed a complex process of gravel storage and intermittent resupply from the residual reach, allowing the authors a detailed analysis of frequently occurring bedload pulses. These transport features are triggered by increased discharges during floods in the residual reach and created pronounced anticlockwise bedload hysteresis or, with a temporal shift to the event peak, caused distinct shifts in the bedload activity downstream. Bedload pulses produce very high bedload fluxes while in transit, tend to increase bedload flux in the post-event phase, and can alter and reduce the upstream sediment storage leading to a lowering of bedload availability for future pulses. The observed time lags between main discharge events and the arrival of the macro-pulses are correlated with mean water discharge during pulse propagation, thus enabling a prediction of the pulse arrival at the monitoring station solely based on the hydrograph. In combination with the hydrological setup of the reach, the observed bedload pulse time lags allowed an estimation of pulse velocities in the range 0.002 - 0.05 m s(-1). (C) 2016 Published by Elsevier B.V.
Autor/innen der BOKU Wien:
Aigner Johann
Habersack Helmut
Hauer Christoph
Kreisler Andrea
Rindler Rolf
BOKU Gendermonitor:


Find related publications in this database (Keywords)
Bedload discharge
Bedload pulse
Hydropower affected river
Gravel bed river


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