Computational assessment of sediment balance and suspended sediment transport pathways in subsurface drained clayey soils

•3D dual-permeability model was applied to quantify sediment balance in clay fields.•Three model structures were built to assess uncertainties and transport pathways.•Data and simulations showed that subsurface transport pathways dominated the loads.•Lateral transport contributed to load generation especially in steep field section.•Erosion and sediment transport were controlled by water flow and soil structure.