The Huai River used to flow all the way to the sea through present-day northern Jiangsu province. However, beginning in 1194 the Yellow River to the north changed its course southwards to run into the Huai River, and changed back and forth several times over the next 700 years. The resulting silting was so heavy that after the Yellow River changed back to its northerly course for the last time in 1897, the Huai He is no longer able to go through its old course. Instead it pools up into Lake Hongze, and then runs southwards towards the Yangtze River. The North Jiangsu Irrigation Main Channel also diverts a bit of its water along its old historical course. Jiangsu (Simplified Chinese: æ±è; Traditional Chinese: æ±è; Hanyu Pinyin: ; Wade-Giles: Chiang-su; Postal System Pinyin: Kiangsu) is a province of the Peoples Republic of China, located along the east coast of the country. ... Events November 20 - Palermo falls to Henry VI, Emperor of the Holy Roman Empire December 25 - Henry VI is crowned king of Sicily. ... 1897 (MDCCCXCVII) was a common year starting on Friday (see link for calendar). ...
The unusual course of the river makes it extremely prone to flooding.