Seasonal Variation of Turbidity in the Huayang Lake Group and Its Coupling Mechanisms Driven by Water Level and Wind Field

Drawing on continuous multi-year monitoring data (2019–2024) from the Huayang Lake Group, we constructed a water level–wind speed–turbidity coupling model to decode the driving mechanisms behind the lake’s seasonal turbidity variations. We identified a distinct “turbid-winter, clear-summer” dynamic, primarily governed by the interplay between water level fluctuations and wind-driven mixing. Crucially, the study established quantitative thresholds for high-turbidity events: the combination of water levels below 12.0 m and wind speeds exceeding 5 m/s triggers a sharp surge in turbidity, reaching 300–480 NTU. Sensitivity analyses from the validated model indicate that every 1 m drop in water level corresponds to an average turbidity increase of 40–60 NTU, whereas a 1 m/s increase in wind speed adds 30–50 NTU. In contrast, maintaining water levels above 15.0 m significantly strengthens vertical water column stability, effectively buffering against wind-induced sediment resuspension. Additionally, significant seasonal variations in calibrated model parameters further corroborated the amplifying effect of low water levels and strong wind-waves on resuspension during winter and spring. Ultimately, this study proposes a novel dual-parameter early warning mechanism and provides practical guidance for non-flood season water level management, offering vital insights for the ecological conservation of Yangtze-connected shallow lakes.