| 20 Aug 2026
RDycore-sediment v1.0: A two-dimensional sediment transport model for Earth system modeling
Abstract. Sediment transport links land-surface erosion, river and floodplain morphology, reservoir storage, water quality, and downstream material delivery. Yet scalable two-dimensional (2-D) sediment transport representation remains limited in large-scale Earth system modeling frameworks. We present RDycore-sediment v1.0, an extension of the River Dynamical Core version 1.0 (RDycore v1.0), which adds conservative multi-class suspended sediment transport and local water-bed sediment exchange to RDycore v1.0’s finite volume shallow water formulation. The model routes class-specific suspended sediment mass according to RDycore simulated hydrodynamics and accounts for bed erosion, deposition, active-layer exchange, and substrate-layer bed storage. In this first version, bed sediment mass is updated diagnostically, but bed elevation remains fixed and sediment dynamics does not feed back onto flow dynamics. Additionally, we extended the hydrodynamics model within RDycore to include hydrostatic reconstruction of the flow variables. RDycore-sediment is evaluated with both ideal and realistic benchmark cases, including 1) two conventional passive transport benchmarks, 2) a dam break erosion and deposition comparison with TELEMAC/GAIA, 3) a three-class method of manufactured solutions case, and 4) a Hurricane Harvey Houston benchmark driven by runoff and soil erosion inputs. In idealized tests, RDycore-sediment preserves passive transport and lake-at-rest states, reproduces TELEMAC/GAIA erosion and deposition in the idealized dam break, and achieves first-order convergence. For the Hurricane Harvey case, RDycore-sediment and TELEMAC/GAIA simulate comparable event-scale timing and total bed mass changes. The Hurricane Harvey case also highlights the importance of including coastal backwater effects and the use of well-balanced hydrodynamics for sediment applications in complex urban watersheds, as small errors in velocity and shear stress can bias the calculation of bed erosion and deposition. RDycore-sediment provides a scalable foundation for 2-D sediment routing in river and floodplain systems and supports future coupling with Earth system models across the land-river-ocean continuum.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Geoscientific Model Development.
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