Mackenzie River great depths to bedrock. A characteristic feature of the delta is its numerous pingos, or hills of earth-covered-ice – some 1,400 of them. The Peel River, carrying much of the runoff from the northern Yukon, joins in the delta at a point northeast of Fort McPherson. Below there, the Mackenzie diverges into several large channels with the largest heading north-northeast, emptying into the Beaufort Sea west of Tuktoyaktuk. At , the Mackenzie River drainage basin encompasses nearly 20 percent of Canada. About , or 54 percent of the basin, lies above Great Slave Lake. Permafrost underlies about three-quarters of the
Dongting Lake water from the Yangtze flows into the lake, enlarging it greatly. The lake's area, which normally is (data before 1998), may increase to in flood season, when vast amounts of water and sediment from the Chang Jiang flow into the lake. The lake is also fed by four major rivers: the Xiang, Zi, Yuan and Li rivers. Small rivers also flow in, the most famous one being Miluo River where a famous poet Qu Yuan committed suicide. In addition, the Xiao River flows into the Xiang near Yongzhou, before the Xiang flows into the lake. Ocean-going vessels can travel through