Characteristics of ice regime in the lower Yellow River

The characters of ice regime in the lower Yellow River are as follows:the reach is completely freezing in winter for some years,and freezing-free for some others;in the reach,the freeze-up date is earlier,the break-up date later;and the freeze-up period is longer,and the ice-cover is thicker and solider than that of the upstream;the ice flood is characteristics of the small flow,high water level and increase from the upriver channel to downriver channel.In recent 20 years,the ice regime has changed with the discharge decreasing at large scale,the sustaining high temperature and the reserwirs, control,so that the dates of the freeze-up and break-up are brought forward;the river length and ice volume of the freeze-up,the channel storage and the times of ice dam and ice jam are shorted;and the frequency of frozen-free years increases.