http://www.infoplease.com/ipa/A0001440.html
"1642
China: rebels destroyed Kaifeng seawall; 300,000 drowned."
i have just done a little googling and not found anything yet ... does anyone know more of this?
edit:
i also found this:
http://usuarios.lycos.es/drinkingwater/The%20World's%20Water%20-%20Water%20Conflict%20Chronology.htm
"Date ...... 1642
Parties Involved ..... China; Ming Dynasty
Basis of Conflict ...... Military tool
Violent Conflict? ......Yes
Description ..... The Huang He's dikes have been breached for military purposes. In 1642, "toward the end of the Ming dynasty (1368-1644), General Gao Mingheng used the tactic near Kaifeng in an attempt to suppress a peasant uprising."
Sources .....Hillel 1991 "
also:http://ic.ucsc.edu/~tlay/eart80a/Lectures/lecture21.html
"human activity has also resulted in great floods, sometimes intentionally. An example is the history of the Yellow River, which has been used more than once as a massive weapon. The most recent case occurred in 1938, when the Japanese were advancing southwestward into China in their attempt to take over the country. They had overrun the city of Kaifeng, driving Chiang Kai-Shek before them. In an act of desperation, to slow the advancing Japanese, the Chinese leader mined the levees of the Yellow River, which build up high above the surrounding flood plain due to the high sediment load as the river drops out of the highlands to the west. The induced flood, released through a 1/4 mile wide gap in the levees created a massive bog, which actually mired the Japanese, who redirected their advance toward the south. The Yellow River actually changed its course, merging into a Yangtze tributary 400 miles south of its prior track, but near to historic drainages from 1494 and 1854. The stratagem was somewhat successful, but a huge price was paid by the Chinese. The massive flood, advancing at 5 mi/hr immersed 21000 square miles. Over 1 million Chinese perished in the flood, and massive crop losses caused famine. The river returned to its northeastward drainage in 1947. The river normally floods almost every other year, with 1500 floods in the last 2500 years due to natural causes. The previous human-induced flood was in 1642 when General Gao Mingheng also intentionally collapsed the levees in order to suppress a peasant rebellion."