Hanfeng Lake: water over a drawdown zone

The number that made the lake is 55 square kilometres. When the Three Gorges reservoir filled, the water in the Pengxi, the tributary that reaches Kaizhou, rose and fell with the season, and the band of exposed shore left behind in the district measured that area. A drawdown zone of that size is not scenery; it is mud in one season and weed in another, and a boundary that moves through the year. The lake was built artificially to reduce the drawdown zone's effect on the district's ecology, using the water of the same tributary. Its main feeding streams are the Taoxi, the Dong and the Nan.

At the end of 2017 the lake's water-level regulating dam began operating and holding water, and the regime changed from seasonal to fixed. The lake is now kept between 170 and 175 metres, stores 80 million cubic metres and covers 14.8 square kilometres at normal level, which makes it the largest urban artificial lake in inland western China. A fixed level means a fixed shoreline: paths, bridges and planting can be built to a known water line instead of following a shore that moves. The lake lies at Fengle, on the upper Pengxi. Kaizhou has been developing around it in recent years.

Kaizhou's own account of what the reservoir did is administrative. Kaixian was a county of large population, resources and farmland, and also a county of heavy resettlement; after the reservoir filled, the district was made up of three areas, Zhongji, Ankang and Pingqiao. It was not alone. Filling the reservoir drowned 129 towns, among them the large city of Wanzhou, the mid-sized city of Fuling and a dozen small cities, and resettlement took 45 percent of the whole project's investment; Chongqing, created in 1997 around the reservoir, took on 85 percent of the migrants. The lake is the local answer to a national number.