Dynamic Coupling Model of Water Environment of Urban Water Network in Pearl River Delta Driven by Typhoon Rain Events

Abstract

Typhoon rain dominates meteorology-rainfall-runoff-environmental factor changes at the regional scale and regulates water resources in the river network area by means of multi-field coupled meteorological, hydrological, and geographic models, shaping complex water resources and water environment scenarios in the Pearl River Delta. Because of limitations in the monitoring capacity of the typhoon process, quantifying the ephemeral processes and spatial heterogeneity information of typhoon rain events is difficult, which makes the degree of research on typhoon rainfall-runoff transformation processes low and the progress in regional water resources and water environment evaluations based on typhoon events slow. In this study, typhoon rain event data, namely, remote-sensing spectra, measured water quality parameters, and meteorological factors, in the Pearl River Delta during 2022 were first collected. Next, a dynamic coupling model between typhoon rain events and the water network environment was established to simulate and predict the water environment conditions of the Zhongshan City water network controlled by the regulation of typhoon rain events. By inputting the quantitative data of the typhoon rain events, the water environment conditions of the river network in Zhongshan City after the typhoon rain events were simulated and output. The results showed that the distribution of dissolved oxygen concentrations and ammonia nitrogen concentrations were consistent: the concentration was highest in the central urban area, which is more urbanised than other areas, and it was lowest in the area far from the urban centre. Moreover, under the influence of Typhoon Ma-on, the water environment of the Zhongshan City water network changed over time: dissolved oxygen concentrations decreased and then increased, and ammonia nitrogen concentrations increased and then decreased. The water quality prediction model proposed in this study helps to improve the understanding of the dynamic impact of typhoon rain on the water quality of an urban water network in the Pearl River Delta and is conducive to improving the formulation of water environment control strategies during typhoon transit.