Numerical Simulation of Longitudinal and Lateral Channel Deformations in the Braided Reach of the Lower Yellow River

Modelling dam-break flows over mobile beds using a 2D coupled approach

“…The memory layer is further divided into m smaller sub-layers, with the thickness and gradation of each sub-layer being represented by DH m and DP mk , respectively. The adjustment procedure of the size distribution of surface bed material can be classified into two cases of bed scour and bed deposition, with a detailed description of the procedure being given in Wang et al [34].…”

Modelling hydrodynamics in the Rio Paraná, Argentina: An evaluation and inter-comparison of reduced-complexity and physics based models applied to a large sand-bed river

“…Such models may also be combined with equations representing sediment transport and channel bank erosion in order to simulate the evolution of river morphology (Olsen, 2003;Duan and Julien, 2005;Jang and Shimizu, 2005). However, the application of integrated flow-sediment transport models has, to date, focused largely on idealised or laboratory channel configurations (Wu et al, 2000;Defina, 2003;Rüther and Olsen, 2005;Abad et al, 2008) or the evolution of natural channels over relatively short time periods (Darby et al, 2002;Olesen and Tjerry, 2002;Chen and Duan, 2008;Fischer-Antze et al, 2008;Wang et al, 2008;Zhou et al, 2009). This restricted focus of such physically based morphodynamic models reflects their recent development and availability, and their high computational demands.…”

Seasonal variations in composite riverbank stability in the Lower Jingjiang Reach, China

“…It should be noted that the selection of some parameters such as r t and c 1 for the cohesive upper bank soils partly refers to the parameter estimation for the cantilever stability analysis conducted by Thorne and Tovey (1981). In order to accurately assess the overhang width and the corresponding degree of stability of a composite riverbank in the LJR, a submodel of bank erosion is usually integrated with a submodel of two-dimensional bed deformation (Darby et al, 2007;Rinaldi et al, 2008;Wang et al, 2008), which needs to be conducted in the future. Existing field surveys in the LJR indicate that the critical width of an overhanging block ranges from 0.5 to 0.6 m during a drawdown period and the mean overhang width is usually less than 20 cm during a dry season.…”

“…Riverbanks with different soil compositions differ in aspects of erosion mechanisms and influencing factors, and previous studies mainly focus on the slope stability analysis of homogeneous noncohesive and cohesive riverbanks (Osman and Thorne, 1988;Darby and Throne, 1996;Nagata et al, 2000;Darby et al, 2002;Wang et al, 2008). For non-cohesive riverbanks, scour at the bank-toe is due to a loss of individual particles, and bank failure usually occurs due to an over-steep slope that is greater than the angle of repose of submerged sediment Nagata et al, 2000).…”

“…For non-cohesive riverbanks, scour at the bank-toe is due to a loss of individual particles, and bank failure usually occurs due to an over-steep slope that is greater than the angle of repose of submerged sediment Nagata et al, 2000). For cohesive riverbanks, toe scour occurs as crumbs of soil rather than individual particles, as they are bound tightly by electromechanical cohesive forces (Lawler et al, 1997;Thorne et al, 1997;ASCE TC, 1998), and the ratio of resisting to driving forces acting on a potential failure plane is less than unity as a cohesive bank becomes unstable (Darby and Throne, 1996;Osman and Thorne, 1988;Darby et al, 2002;Wang et al, 2008). For example, Osman and Thorne (1988) proposed a slope stability analysis of planar failure for steep, cohesive and non-layered riverbanks in response to lateral erosion or bed degradation.…”