The scientists studied how water quality and quantity in the Middle-lower Hanjiang River are affected by water diversion projects and cascade reservoirs. They used a model to analyze the impact of these projects on the river's water flow and pollution levels. The results showed that the water level decreased, annual runoff significantly decreased, and water quality worsened after the South-to-North Water Diversion Project. The Yangtze-Hanjiang Water Diversion Project partially offset the negative effects of the first project but led to increased water pollution. Overall, these projects have caused water resource reduction and quality issues in the Middle-lower Hanjiang River that need attention.