A novel framework for turbidity source analysis of the urban lakeside river network

Quantifying turbidity source is essential but complex for precise environmental rehabilitation of worldwide urban lakeside river networks impaired by turbidity. A new turbidity source analysis framework including in-situ sampling, vessel monitoring, remote sensing, and MIKE 11-based simulation was proposed, where the critical processes of flow reversal from turbid lake, navigation, and urban non-point source in urban lakeside river networks were explicitly considered. The case study results showed that turbidity problem was primarily led by suspended inorganic matter (58%), followed by suspended organic matter (19%) and other matter. The Tiaoxi River and busy shipping contributed most to annual total suspended solids (TSS) load of target river, with the same percentage of 34%. The turbid Lake Taihu provided 31% of total TSS load, focusing on autumn and winter months. Tiaoxi River load was highly concentrated on the storm events, which accounted for 71.4% of annual Tiaoxi River source. Coronavirus disease (COVID-19) lockdown and Spring Festival holiday has a significant effect on the change of shipping and Tiaoxi River sources, through limiting the waterway transportation and the market demand for building materials. River estuary’s vegetation interception belt, shipping restriction and rerouting and integrated catchment management were advised to mitigate the urban river network turbidity.