Lake Taihu's water exchange cycle has changed in the past decade, leading to increased water inflow and a shorter exchange period. The increase in water inflow is mainly due to changes in the western part of the lake, linked to water diversion along the Yangtze River. This change is affecting the traditional water quality pattern of the lake, causing a more uniform distribution of water quality between the east and west parts of Lake Taihu. The water quality in the eastern part of the lake is showing a decreasing trend as a result.