Ruler of the Yangtze River - Introduction to the scientific value of the Baiheliang inscription: The scientific value of the Baiheliang inscription Among the hydrological inscriptions of the Three Gorges of the Yangtze River, the Fuling Baiheliang inscription is particularly precious. The "stone fish water mark" it set formed an "ancient hydrological station", which was a major pioneering work in the field of ancient hydrological observation. Among the 165 existing inscriptions, 108 involve hydrological value. They truly record the water level conditions in 72 dry years over more than 1,200 years from before the first year of Guangde in the Tang Dynasty to the 1960s, and systematically reflect the dry years in the Yangtze River Basin. The law of water level changes provides scientific basis for Yangtze River navigation and the construction of water conservancy projects. It is known as "the world's first ancient hydrological station".