Comparing turbulent bursts dynamics under wind- versus ship-induced waves in Lake Taihu, China

Benthic turbulent bursts play a crucial role in sediment resuspension and endogenous pollution in large, shallow lakes. This study aims to compare the dynamics of bursting events under various wind- and ship-induced waves in the near-bed regions of Lake Taihu, China. Utilizing in-situ observations with high-frequency Acoustic Doppler Velocimetry, we revealed several distinct turbulence patterns associated with these two types of disturbances. Under wind effects, the time fractions of bursting events during the survey were relatively low, remaining below 20 %. Quadrant analysis showed that when wind speeds exceeded the threshold for sediment resuspension, i.e., 4 m/s, ejection and sweep events dominated the bursting processes, contributing more to benthic shear stress than inward and outward interactions. In contrast, under shipping conditions, the time fractions of bursting events increased to 21–34 %, with the benthic shear stress predominantly influenced by single-quadrant events, either inward or outward interaction. Moreover, bursting events under shipping exhibited longer residence times and infrequent quadrant transitions in near-bottom regions, suggesting more stable states compared to wind-induced bursts. Spectral analysis revealed − 5/3 energy decay in both wind- and ship-induced spectra, while the spectral densities of u′ are higher than those of w′ under shipping. This study focused on the contrasting dynamics of turbulent bursts driven by wind- and ship-induced waves, providing insights into the remediation of other polluted shallow lakes with heavy navigation traffic.