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A model‐based analysis of meander restoration
Author(s) -
Krapesch Gerald,
Tritthart Michael,
Habersack Helmut
Publication year - 2009
Publication title -
river research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.679
H-Index - 94
eISSN - 1535-1467
pISSN - 1535-1459
DOI - 10.1002/rra.1236
Subject(s) - meander (mathematics) , aggradation , geology , floodplain , flood myth , flow (mathematics) , channel (broadcasting) , hydrology (agriculture) , turbulence , shear stress , environmental science , flow conditions , mechanics , geotechnical engineering , geomorphology , computer science , geography , physics , fluvial , geometry , archaeology , structural basin , computer network , mathematics , cartography
Meander reconnection is becoming a widely applied river restoration measure, aiming to enhance the ecological status of river systems. Based on a physical model study and a 3D hydrodynamic‐numerical simulation, the effects of different forms of meander reconnections on flow dynamics, water level and river morphology are investigated in present study including retention of the old main channel for flood protection when the bankfull discharge is exceeded. The distribution of total discharge between the reconnected meander bend and the flood channel during floods decreases flow velocity and bed shear stress and leads to aggradation. At higher discharges, the flow velocity decreases in the meander bend whereas it increases in the flood channel. The controlling parameter for flow diversion—hence for flow velocity and bed shear stress—is the elevation of the ramp diverting the flow. Using the hydrodynamic model RSim‐3D a particle tracing study simulated the trajectories of conservative particles at six vertical levels. The vertical movements of the particles on trajectories going through the reconnected meander were investigated by calculating the number of level changes of each particle. This novel approach in simulating particle movement in channels facilitating qualitative decision‐making in the framework of river restoration issues. In particular, it reveals information regarding heterogeneity and turbulence of the water and also nutrient movements under variable flow conditions and can thus help answer restoration‐related ecological questions. Copyright © 2009 John Wiley & Sons, Ltd.