Researchers monitor the soil condition at water level fluctuation zone of the Three Gorges Reservoir in Zhongxian County, southwest China's Chongqing, April 10, 2021. The Three Gorges project is a vast multi-functional water-control system on the Yangtze River, China's longest waterway, with a 2,309-meter-long and 185-meter-high dam. The water levels of the reservoir area inevitably fluctuate on an annual discharge-storage cycle between 145m to 175m at the dam. The water level fluctuation zone also encounters some eco-environmental problems, including soil erosion and non-point source pollution. Researchers of the Institute of Mountain Hazards and Environment, Chinese Academy of Sciences (CAS) have conducted comprehensive investigations on soil, plants, hydrology, water quality and sediment in the area. Their study has important implications on better running the function of the Three Gorges Reservoir and the safety of local ecological environment. (Xinhua/Jin Liwang)