The 1642 flood was man-made, caused by the attempt of the Ming governor of Kaifeng to use the river to destroy the peasant rebels under Li Zicheng who had been besieging the city for the past six months [REF].
Between 1851 and 1855,[REF][REF][REF] it returned to the north amid the floods that provoked the Nien and Taiping Rebellions.