river could not easily flow into the lower section, while water in the lower section could not find an outlet to the sea. The problem worsened in the Second World War, when the Nationalist government, in an attempt to check the pace of the Japanese invasion, flooded the lower Huai basin by opening the Yellow River's southern levee. The main stem of the Yellow River flowed through the levee breach for the next nine years, further disrupting the Huai river system. The result of these changes was that water from the Huai River pooled up into Lake Hongze, and then ran southwards towards the Yangtze River. Major and minor floods occurred frequently, with the area suffering droughts in between floods. In the 450 years to 1950, the Huai River saw, on average, 94 major floods per century. Attempts to solve the Huai River's problems have focused on building outlets for the Huai River into the Yangtze River and the sea. Currently, the major part of the river's flow enters the Yangtze River via Lake Hongze. The North Jiangsu Main Irrigation Canal also diverts some of its water along its old historical course to the sea, and is planned to be upgraded with a new parallel channel. Several former tributaries also carry some water to the sea. Tributaries There are many tributaries of the Huai River. There are 15 main tributaries cover an area of more than each, and 21 main tributaries have a catchment area larger than . The main tributaries on the Huai river (listed from upstream to downstream) are as follows: References External links Huai River Rivers of Jiangsu Rivers of Henan Rivers of Anhui Tributaries of the Yangtze River