Ice regime characteristics in the Ningxia-Inner Mongolia reach of Yellow River

The characteristic values of drift ice,the freeze up and breakup dates in the Ningxia Inner Mongolia reach of Yellow River from 1950 to 2004 are analyzed,and their distributions are also showed.The maximum channel-storage increment are summarized.The result shows that the break-up from upstream to downstream in the Ningxia Inner Mongolia reach of Yellow River,the channel-storage capacity are constantly set free and added along the river,and the flood peak of ice flow is added along the river during the break-up period.The formation,development and dissolution course of ice regime are mainly decided by the river pattern,the hydrometeorological regime and human activity.The reservoir operation is an important influence on the evolution of ice regime.