Numerical Study of the Hydrodynamic and Sediment Transport Process in a Subtropical Water Reservoir: the Impacts of Storms and Winds

Abstract

A three-dimensional (3D) numerical model was developed to investigate the thermodynamic and sediment processes in a subtropical drinking water reservoir. Data-driven models were also established to generate the inflow conditions. The modelling outputs revealed that climatic forces such as storms and winds significantly impact lake stratification and mixing processes. The sediment transport is driven by storm events, during which sediment delivery to the reservoir is dominated by allochthonous flux. The sediments are transported from riverine zones to transition zones and finally to lacustrine zones. It is estimated that sediment accumulation could have reached 100,000 kg during the largest storm event in February 2015.The winds can lead to a strong vertical water cycle, especially at the centre of the reservoir, and strong winds result in bed erosion in shallow regions. The outcomes of this paper benefit future research by providing a modelling approach for understanding the hydrodynamics of lakes and reservoirs under a variable climate, and also the local water utility by providing insights for an improved management of the reservoir of this study. Article Highlights:• Coupled data-driven and numerical model of a shallow water reservoir • Storm and winds have significant impacts on the lake stratification and mixing processes. • Sediment transport dominated by allochthonous flux during storm.• Strong winds result in the bed erosion in shallow regions of the lake.

Effects of dimensionality on the performance of hydrodynamic models

“…A large variety of different numerical models have been used for simulating temperature and hydrodynamics in lakes and reservoirs, as well as the biogeochemical and ecological processes that depend on it (e.g. Dissanayake et al, 2019;Guseva et al, 2020;Wang et al, 2020;Xu et al, 2021). While the mechanistic description of underlying physical processes is identical or at least similar in all models, they differ in their dimensionality, i.e.…”

“…Regardless their complexity, 3D models are widely applied, e.g. POM (Beletsky and Schwab, 2001;Song et al, 2004), ELCOM (Carpentier et al, 2017;Marti et al, 2011;Zhang et al, 2020) and Delft3D-FLOW (Soulignac et al, 2017;Bermúdez et al, 2018;Baracchini et al, 2020;Guénand et al, 2020).…”

Effects of dimensionality on the performance of hydrodynamic models for stratified lakes and reservoirs

“…A wide variety of different numerical models have been used for simulating temperature and hydrodynamics in lakes and reservoirs, as well as the biogeochemical and ecological processes that depend on them (e.g., Dissanayake et al, 2019;Guseva et al, 2020;Wang et al, 2020;Xu et al, 2021). While the mechanistic description of underlying physical processes is similar in all models, they differ in their dimensionality, i.e., the number of spatial dimensions that are considered in the model.…”

Reply on CEC2

“…A large variety of different numerical models have been used for simulating temperature and hydrodynamics in lakes and reservoirs, as well as the biogeochemical and ecological processes that depend on it (e.g. Dissanayake et al, 2019;Guseva et al, 2020;Wang et al, 2020;Xu et al, 2021). While the mechanistic description of underlying physical processes is identical or at least similar in all models, they differ in their dimensionality, i.e.…”