Sediment transport model

Lopez, F., and Garcia, M. (1998) Open-channel flow through simulated vegetation suspended sediment transport modeling, Water Resour. Res. 34(9), 2341-2352. 

In recent years several numerical sediment transport models have been presented, which use either the quasi-Lagrangian or the Eulerian treatment. In the quasi-Lagrangian approach,... 

It is a promising perspective to integrate the sediment transport model described in Kuhrts et al. (2004) into the biogeochemical model components of Neumann et al. (2002) to identify the transport paths of organic and inorganic particulate matter from the sources (rivers and primary production in the surface layer) to the deposition areas in the deep basins, where accumulation of new sediment is observed. 

Figure 1. Based on these values. Figure 1 includes the theoretical relationship between Kd and [NH4 ] according to equation (8). The interpretation of the radiocesium KdS in Figure 1 clearly shows that Cs in the aquatic environment obeys ion-exchange theory. The ion-exchange model allows the Kp of this radionuclide in sediment transport models to be predicted from environmental variables (i.e. the quantity of FES in the sediments and the pore-water concentration), rather than to be erroneously treated as a constant.

The combined wave and current model predicts the cross-shore variations of the hydrodynamic variables used in the following sediment transport model for given beach profile, water level, and seaward wave conditions at x = 0. The bottom sediment is assumed to be uniform and characterized by dso, the median diameter Wf, sediment fall velocity and s, sediment specific gravity. 

The combined wave and current model for obliquely incident waves by Kobayashi et al is improved by including the finite-depth effect on the relationship between the oscillatory horizontal velocity and free surface elevation as well as the wind stresses for future field applications. The numeric integrations involved in the bottom shear stresses and energy dissipation rate are replaced by sufficiently accurate analytic expressions. These modifications improve the computational efficiency and numeric stability of the wave and current model. The sediment transport model developed by Kobayashi et for normally incident waves is extended... 

J. A. Bailard, An energetics total load sediment transport model for a plane sloping beach, J. Geophys. Res. 86(C11), 10938-10954 (1981). 

With recent advancements in numerical models of fluid mechanics and sediment transport, modeling has become a key tool for evaluating sediment transport behavior and associated contaminant transport and fate. While state of the art, research-oriented models may contain many of the detailed mechanisms by which solids deposition and scour may occur, the current widely distributed (i.e., public domain) engineering-oriented models for these processes necessarily employ simplifications of some mechanisms due to constraints in computational time, model development time, and site data availability. These models aim to represent the bulk behavior of solids or classes of solids, rather than modeling the forces acting on each individual particle. 

Two-dimensional (2D) models represent a second tier of spatial complexity with respect to sediment transport models. Models in this class have become more prevalent during the last couple of decades due to advancements in computer hardware and software capabilities. Two-dimensional models typically solve the depth-averaged flow continuity and Navier-Stokes equations with respect to hydrodynamic behavior and mass balance equations with respect to sediment transport. Computational methods employed in 2D models include finite difference, finite element, and finite volume. Examples of 2D models include Environmental Eluid Dynamics Code (EFDC), SEDZLJ, SEDZL, USTARS, MIKE21, and Delft 2D. 

Three-dimensional (3D) models represent the highest tier of spatial and process complexity and solve the flow continuity equation and the Navier-Stokes equations for conservation of mass and momentum in three-dimensional space. Three-dimensional models are favored over depth-averaged models for water body systems where density stratification occurs or hydraulic structures significantly impact hydrodynamic behavior. Examples of 3D coupled hydrodynamic/sediment transport models include EEDC, ECOMSED, MIKE-3, RMA-10, and Delft 3D. 

The WASP model incorporates erosion in an analogous manner to how it handles settling, relying on user-specified rates of erosion for each solids type in the model. Similar to settling rates, input erosion rates can vary in time and space. As discussed for WASP settling, this is a flexible approach that lends itself well to either very simple representation of sediment dynamics or to coupling of the WASP model to an independent sediment transport model for a more sophisticated representation. 

The SEDZLJ model was developed at the University of California at Santa Barbara and published in 2001. Similar to the EEDC model, SEDZLJ is capable of simulating sediment transport processes for multiple particle size classes in one-, two-, and three-dimensional space. The model is implemented using an independent hydrodynamic model, such as ECOM, to drive the simulation. The model is unique among sediment transport models in that it directly utilizes data obtained using the Sedflume device, which measures changes in erosion rate with depth (Jones and Lick, 2001). 

As discussed previously, the formulations in sediment transport models depend on empirical relationships between shear stress and transport rates based on experimental data. Although empirical formulations for erosion and deposition are consistent with sediment transport theory, they are not directly based on theoretical considerations. Therefore, regardless of the level of complexity afforded by a particular model framework, model calibration is an essential component of any sediment transport model application. Data need required to support model calibration are intense and ideally include the following ... 

Concentrations of total suspended sediment, and of PCBs adsorbed to suspended sediment, are sensitive to daily flow rates, indicating that deposition and scour of contaminated material and water column fluxes of PCBs respond to variations in flow. Hydrodynamic and sediment transport modeling played an important role in the investigation and remedy determination for the Fox River/Green Bay site. Hydrodynamic modeling included one-dimensional steady-state models, one-dimensional dynamic... 

Jones, C. and W. Lick. 2001. SEDZLJ A Sediment Transport Model. Dept, of Mech. and Env. Eng., University of California, Santa Barbara, May 29. 

Papanicolaou, A.N., M. Elhakeem, G. Krallis, S. Prakash, and J. Edinger. 2008. Sediment transport modeling review—Current and future developments. J. Hydraul. Eng., 134(1) 1-14. 

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