In an attempt to win more time for the preparation of the defense of Wuhan , the Chinese opened up the dikes of the Yellow River in Huayuankou , Zhengzhou on 9 June . The flood , now known as the 1938 Yellow River flood , forced the Japanese to delay their attack on Wuhan . However , it also caused around 500,000 to 900,000 civilian deaths , flooding many cities in the north of China
1938 Yellow River flood
1938 Yellow River flood
Battle of Wuhan