Presenters-0708
From CSDMS
CSDMS 2026: Modeling Landscapes in Motion
Three ingredients for numerically efficient 2D delta morphodynamic modeling
Abstract
Several models exist to simulate 2D deltaic morphodynamics, but most remain computationally expensive. Here I show that minor simplifications in the governing equations lead to massive increase in computational efficiency. First, the model solves the two-dimensional steady-state shallow water equations while neglecting momentum advection, a term here shown to have a small influence on large-scale and long-term morphodynamics. The resulting momentum equations are linearized with respect to velocity and water level, then solved iteratively. Second, all bed-material transport is represented as suspended load (non-equilibrium) rather than bedload (at-equilibrium). Sediment concentration is assumed to be at steady state, though not necessarily in equilibrium with local resuspension. When discretized numerically, steady-state non-equilibrium transport is mathematically equivalent to at-equilibrium transport subjected to a spatial convolution filter, which explains why the non-equilibrium formulation is orders of magnitude more stable. Third, downslope transport is represented as a bed-elevation diffusion term, with diffusivity proportional to total sediment flux and computed from both upslope and downslope cells. This formulation, equivalent to introducing a transverse sediment flux, is stable when computed with an implicit algorithm and automatically captures bank erosion. The model reproduces large-scale deltaic morphologies that are realistic and comparable to those generated by full hydrodynamic and sediment-transport models, but at a fraction of the computational cost. The model also includes tide and wave hydrodynamics, as well as mud transport and vegetation processes, using which a large range of coastal settings can be reproduced.
Please acknowledge the original contributors when you are using this material. If there are any copyright issues, please let us know (CSDMSweb@colorado.edu) and we will respond as soon as possible.
Of interest for:
