Interaction between gravel mining pits and river curvature on maximum scour depth through 2D hydraulic modelling

• Published in: Journal of hydrology (Amsterdam) Vol. 604; p. 127245
• Main Authors: Mohammad-Hosseinpour, Abedin, Molina, José-Luis, Jabbari, Ebrahim
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2022
• Subjects: Gravel mining pits; Maximum scour depth; River morphology; 2D; Maximum scour depth; Gravel mining pits; River morphology
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2021.127245

•Interaction of rivers curvature and gravel mining pits on different curvature channels.•Modelling of river morphology through hydraulic 2D modelling approach (CCHE2D code).•Fluctuations on the maximum scour depth pit from a straight and curvy channel.•Smoothing actions reduces the scour depth pit and the secondary flow increases it.•The reducing effect stems from the asymmetry of the flow velocity in the channel bend. To investigate the interacting effects of rivers curvature and gravel mining pits on rivers morphology, channels with different curvatures were analyzed using a 2D-3D modelling approach implemented through the code CCHE2D. A parameter (Δ: the maximum channel scour depth with existence of pit minus the maximum scour depth without pit) was defined as the net effect of gravel mining pits. The results indicated that the net effect of a pit on the maximum scour depth, from a straight channel to a channel with the curvature (C/L) of 2.38, decreases, and then, increases with higher degrees of curvature. The study of influential parameters showed that the cause of this event is due to the simultaneous effects of two opposing phenomena; while one (smoothing) reduces the Δ, the other (secondary flow) increases it. The reducing effect (smoothing) stems from the asymmetry of the flow velocity in the channel bend. This causes bed deformation in a way that channel experience a gradual decrease in velocity and as a result, less sediment loss. Furthermore, the boosting effect goes back to the existence of secondary flow in the bends, which grows stronger as the amount of curvature increases.