The Three Gorges Dam is far from Chongqing. Why does Chongqing have the most immigrants?

Three Gorges immigrants are extra immigrants and backward immigrants. At present, the highest water level of the Three Gorges175m is calculated according to the foundation of the Three Gorges Dam, but this is relative. Every year, the water will be stored around 65438+ 10, and the water will be withdrawn in March and April of the following year, so the residents below 175 meters must be resettled. The occurrence of geological disasters may be due to the fluctuation of water level and the infiltration of water.