Numerical modelling of hydro-morphological processes dominated by fine suspended sediment in a stormwater pond
Journal of Hydrology
© 2017 The Author(s). Published by Elsevier B.V. Open Access funded by Engineering and Physical Sciences Research Council. Under a Creative Commons license: https://creativecommons.org/licenses/by/4.0/
Fine sediment plays crucial and multiple roles in the hydrological, ecological and geomorphological functioning of river systems. This study employs a two-dimensional (2D) numerical model to track the hydro-morphological processes dominated by fine suspended sediment, including the prediction of sediment concentration in flow bodies, and erosion and deposition caused by sediment transport. The model is governed by 2D full shallow water equations with which an advection-diffusion equation for fine sediment is coupled. Bed erosion and sedimentation are updated by a bed deformation model based on local sediment entrainment and settling flux in flow bodies. The model is initially validated with the three laboratory-scale experimental events where suspended load plays a dominant role. Satisfactory simulation results confirm the model’s capability in capturing hydro-morphodynamic processes dominated by fine suspended sediment at laboratory-scale. Applications to sedimentation in a stormwater pond are conducted to develop the process-based understanding of fine sediment dynamics over a variety of flow conditions. Urban flows with 5-year, 30-year and 100-year return period and the extreme flood event in 2012 are simulated. The modelled results deliver a step change in understanding fine sediment dynamics in stormwater ponds. The model is capable of quantitatively simulating and qualitatively assessing the performance of a stormwater pond in managing urban water quantity and quality.
The work is supported by the UK EPSRC grant (No. EP/K013661/1) and the open fund grant (No. SKHL1607) from Sichuan University.
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.
Published online 7 November 2017