China

Plains of the middle and lower Yangtze

East of Yichang, in Hubei province, a series of plains of uneven width are found along the Yangtze River (Chang Jiang). The plains are particularly wide in the delta area and in places where the Yangtze receives its major tributaries—including large areas of lowlands around Dongting, Poyang, Tai, and Hongze lakes, which are all hydrologically linked with the Yangtze. The region is an alluvial plain, the accumulation of sediment laid down by the rivers throughout long ages. There are a few isolated hills, but in general the land is level, lying mostly below 160 feet (50 metres). Rivers, canals, and lakes form a dense network of waterways. The surface of the plain has been converted into a system of flat terraces, which descend in steps along the slopes of the valleys.