Search results for " channel geometry"

showing 2 items of 2 documents

Experimental observations of upstream overdeepening

2005

The issue of morphodynamic influence in meandering streams is investigated through a series of laboratory experiments on curved and straight flumes. Both qualitative and quantitative observations confirm the suitability of the recent theoretical developments (Zolezzi & Seminara 2001) that indicate the occurrence of two distinct regimes of morphodynamic influence, depending on the value of the width ratio of the channel β. The threshold value βR separating the upstream from the downstream influence regimes coincides with the resonant value discovered by Blondeaux & Seminara (1985). Indeed it is observed that upstream influence may occur only in relatively wide channels, while narrower stream…

BedformMechanics of MaterialsMechanical EngineeringOverdeepeningThe issue of morphodynamic influence in meandering streams is investigated through a series of laboratory experiments on curved and straight flumes. Both qualitative and quantitative observations confirm the suitability of the recent theoretical developments (Zolezzi & Seminara 2001) that indicate the occurrence of two distinct regimes of morphodynamic influence depending on the value of the width ratio of the channel β. The threshold value βR separating the upstream from the downstream influence regimes coincides with the resonant value discovered by Blondeaux & Seminara (1985). Indeed it is observed that upstream influence may occur only in relatively wide channels while narrower streams are dominated by downstream influence. A series of experiments has been carried out in order to check the above theoretical predictions and show for the first time evidence of the occurrence of upstream overdeepening. Two different sets of experiments have been designed where a discontinuity in channel geometry was present such that the channel morphodynamics was influenced in the upstream direction under super-resonant conditions (β >βR) and in the downstream direction under sub-resonant conditions (β <βR). Experimental results give qualitative and quantitative support to the theoretical predictions and allow us to clarify the limits of the linear analysis.MechanicsLinear analysisCondensed Matter PhysicsWidth ratioGeology
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Morphological Similarity of Channels: From Linear Erosional Features (Rill, Gully) to Alpine Rivers

2017

The geometric characteristics of incised features such as channels, rills, ephemeral gully, gully, represent the erosional transport regime and the fluvial dynamic equilibrium, and thus it is critical for the understanding of the long-term evolution of natural, agricultural, and anthropogenic landscapes. This paper examines the morphological similarity of channelized erosion in two different environments such as Alpine landscapes and cultivated hillslopes. The first dataset comprises six rivers in the Italian Alps, three in the Carnia region and three in the Dolomites, where erosion is mainly the effect of discharges with high sediment loads or landslides and debris flows. The agricultural …

Channelized erosion on hillslopeRiverchannelized erosion on hillslopes2300Erosion measurementChannel geometrySoil erosionEnvironmental ChemistrySoil ScienceDevelopment3304 Educationriverssoil erosion channel geometry channelized erosion on hillslopes rivers erosion measurement channelized erosion on hillslopes
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