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Anthropogenic Impact on Channel and Extra-Channel Geomorphology of the Dwarkeswar River Basin
Published in Balai Chandra Das, Sandipan Ghosh, Aznarul Islam, Suvendu Roy, Anthropogeomorphology of Bhagirathi-Hooghly River System in India, 2020
Sadhan Malik, Subodh Chandra Pal
One of the most common features in the rapidly flowing bedrock river is potholes (Sengupta and Kale, 2011). In the upper part of the study area, several potholes have been found. The work of Elston (1917), Ängeby (1951), Lorenc et al. (1994) suggested that initiation of flow separation and differential erosion takes place due to the presence of surface irregularities in bedrock in the form of joints or bedding planes. Here, in our study area, surface irregularities can be found in the bedrock in the form of presence of granitic outcrops across the channel flow. A careful investigation from Figure 9.20a–e suggests that all the potholes have been observed in the upper part of the river course and these were degraded through time and process of accumulation significantly dominated here rather than the formation of newer potholes. Apart from this, pothole bed has become the river bed, and few potholes have a greater height than the current river bed elevation. This indicates that they might not have formed in the present fluvial regime rather than they had formed much earlier times.
Bedrock channel morphological modeling on the river in Taiwan
Published in Silke Wieprecht, Stefan Haun, Karolin Weber, Markus Noack, Kristina Terheiden, River Sedimentation, 2016
K.W. Wu, K.C. Yeh, C.T. Liao, Y.G. Lai
As to the cross sectional comparisons of exposed bedrock river reach, the bedrock erosion module is capable of predicting the bedrock erosion depth well temporally but failed to simulate the long-term erosion pattern spatially.
Hydraulic resistance in mixed bedrock-alluvial meandering channels
Published in Journal of Hydraulic Research, 2021
Roberto Fernández, Alejandro J. Vitale, Gary Parker, Marcelo H. García
The study is motivated by the following questions: (1) How does the reach-averaged hydraulic roughness in a bedrock river change under different sediment supply scenarios? (2) How do these changes relate to the ratio of areal alluvial cover to total bed area averaged over a reach? (3) How can the composite roughness including the effect of bedrock and alluvium in a channel of complex shape be better described and quantified so as to inform numerical models? (4) How does reach-averaged hydraulic resistance change due to fluctuations in alluvial cover?