Foreword to the Special Issue on the Yangtze River

Abstract

The Yangtze River is one of the world’s truly great rivers with a length of 6300 km third longest in the world and a drainage area of 1.80 106 km2, housing nearly 400 million people. The annual average flow and sediment transport of the Yangtze River at Datong the downstream least-tide-affected measurement station are 29,500 m3 /s and 327 106 t /year post-Three Gorges Dam . It is interesting to note that the average annual flow of the Yangtze River exceeds the peak flow of the 1993 flood on the Upper Mississippi River at St. Louis, with approximately the same drainage area. Further, while the Yellow River is considered the cradle of Chinese civilization, historians trace the origin of civilization in Yangtze River basin to roughly the same time as the Yellow River basin. Finally, the Yangtze River is home to some of the rarest aquatic species on earth, like the finless porpoise, Chinese alligator, Chinese sturgeon, and paddlefish. It is impossible for six papers to encompass the depth and breadth of the water resources problems, and issues in the Yangtze River basin. However, these papers include a range of interesting contributions on water problems throughout the basin from the headwaters to the estuary. Wang et al. evaluate the geomorphologic and ecologic benefits of step-pools in the debris flow ravines in the headwaters of Yangtze River tributaries in Yunnan Province. They found that step-pools maximize stream stability and greatly increase biodiversity. These findings hold promise for control of debris flows and improvement of the aquatic environment that may extend far beyond the boundaries of the Yangtze River basin. Xie et al. describe the development of shoals in the