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 Dam become safer, since the gorges are notoriously dangerous to navigate. Ships with much deeper draft will be able to navigate upstream from Shanghai all the way to Chongqing. It is expected that shipping to Chongqing will increase fivefold. There are two series of ship locks installed near the dam (). Each of them is made up of five stages, with transit time at around four hours. Maximum vessel size is 10,000 tons. The locks are 280 m long, 35 m wide, and 5 m deep (918 × 114 × 16.4 ft). That is 30 m longer than those on the