Author(s): O. Schlomer
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Keywords: No Keywords
Abstract: The formation of obstacle marks due to local scouring at in-stream obstructions is a classical interface problem of hydraulic engineers and fluvial geomorphologist. However, less attention is given so far on the evolution of obstacle marks at boulder-like obstacles and the morphometric relations of the scour hole (e. g. depth to width, depth to length ratios) during temporal evolution. In long duration flume experiments (t > 5760 min), obstacle marks where modelled on small spatial scale at different flow conditions (subcritical clear-water conditions, unsubmerged and submerged flow stages). Irrespective of flow conditions the morphometric relations evolve similar, basically controlled by scour depth incision, while the thickness of the alluvial layer is a limiting boundary condition. Based on a statistical analysis of the morphometric relationships, three temporal evolution phases are distinguished. A comparison to preserved meso-scale obstacle marks revealed geometrical similarity of morphometric variables (e. g. scour depth, length, width) to some extent.
Year: 2020