Three Gorges Dam dam. An important function of the dam is to control flooding, which is a major problem for the seasonal river of the Yangtze. Millions of people live downstream of the dam, with many large, important cities like Wuhan, Nanjing, and Shanghai situated adjacent to the river. Plenty of farm land and China's most important industrial area are built beside the river. The reservoir's flood storage capacity is . This capacity will reduce the frequency of major downstream flooding from once every ten years to once every 100 years. The dam is expected to minimize the effect of even a "super"
Three Gorges with terrain lowering gradually from south to north. The western and eastern parts of the area, between the southern mountains and Bashan Mountain (), in the north, are comparatively lower; and in the past, the river flowed to the east through the region. As the crust of the locality continued to rise, the river's erosion intensified, and the Three Gorges were carved. The natural beauty of the Three Gorges along the Yangtze River has been appreciated for hundreds of years. In the Northern Wei (北魏) dynasty, Li Daoyuan (郦道元) described them in his work "Shui Jing Zhu" (水经注), or the