Modeling of turbidity dynamics caused by wind-induced waves and current in the Taihu Lake

• Published in: International journal of sediment research Vol. 28; no. 2; pp. 139 - 148
• Main Authors: WU, Ting-feng, QIN, Bo-qiang, ZHU, Guang-wei, ZHU, Meng-yuan, LI, Wei, LUAN, Cheng-mei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2013; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China%Jiangsu Province Hydrology and Water Resource Investigation Bureau, Nanjing 210098, China
• Subjects: Computer simulation; Critical shear stress; Fluid flow; Lakes; Mathematical models; Sediments; Taihu Lake; Turbidity; Turbulence; Turbulent flow; Wind wave frequency spectrum; Wind-driven current; 三维数值模型; 动力学建模; 太湖; 悬浮沉积物; 模型开发; 模型模拟; 浊度测定; 海浪; China, People's Rep., Tai Hu L; China, People's Rep; Wind wave frequency spectrum; Model; Critical shear stress; Taihu Lake; Wind-driven current; Turbidity
• ISSN: 1001-6279
• DOI: 10.1016/S1001-6279(13)60026-8

A simple turbidity model was developed with a sound physical basis based on in situ high-frequency observations of short-term, strong wind-induced sediment suspension in Taihu Lake, China. The validation results show that the model could successfully simulate turbidity caused by strong wind events, despite the relatively poor simulation accuracy for high values of turbidity caused by the entrainment of cyanobacteria by turbulence. The in situ observations and model simulation results indicate that the wind waves were within a narrow spectral band, with spectral energy mainly distributed within the 0.28-0.75 Hz band on opposite sides of the peak frequency. These high-frequency and low-energy wind waves are sensitive to depth filtering. However, the average depth of the lake is only 1.9 m, and wind waves still represent the main force of sediment suspension at the sediment-water interface. Moreover, lake currents were of significance to the maintenance of background turbidity in calm waves or ripples and in the determination of critical shear stress. By considering the spatial distribution of hydrodynamics and sediment, the model can be used to simulate the turbidity of the entire lake as well as boundary conditions for three-dimensional numerical models.