Lingshui is a phenomenon in which river water levels rise significantly due to the resistance of ice to water flow. The natural conditions that produce freezing floods depend on the geographical location of the river and the shape of the river channel. In alpine areas, rivers flow from low latitudes to high latitudes and the river channel shape is wide at the top and narrow at the bottom. There are more opportunities for severe flooding in places where the river channels bend and loop. This is because the lower section of the river freezes earlier than the upper section, and the lower section of the river thaws earlier than the upper section. Moreover, the thickness of the ice sheet is thicker at the bottom and thinner at the top. When ice appears in the lower section of the river, it blocks part of the upstream water and increases the water storage capacity of the river channel. When the ice melts and the river is opened, this part of the water stored in the channel is released sharply, causing peaks to pass downward, and more and more ice water accumulates along the way. , the ice peaks are increasing steadily. When the ice water in the upstream spreads downstream, it encounters narrower sections or corners of the river and forms ice dams, causing the water level in the upstream to rise. Whether ice floods are serious or not depends on the degree of impact of river ice on water levels. Usually only when serious ice or ice dams appear in rivers will the water level rise suddenly and cause serious ice floods.

The hazards of ice floods mainly include three aspects:

① Flood hazards caused by ice jams. It usually occurs during the freezing period, and often occurs at the end of the steep slope and the backwater of the reservoir. It lasts for a long time and gradually raises the water level, causing greater harm to engineering facilities and humans.

② Flood hazards caused by ice dams. Usually occurs during the thawing period. It often occurs in river sections with large latitude differences that flow from south to north. It forms quickly and ice dams form: Afterwards, the water level upstream of the ice dam rises suddenly, the embankments burst, and flooding occurs.

③Hazards caused by ice pressure. Ice pressure is the force that ice acts directly on a building, including the dynamic pressure generated by the impact of drifting ice, the static pressure transmitted to the building due to the shear force of wind and water due to the large area of ????ice, and the entire ice The static pressure generated by the expansion of the capping layer. In February 1929, an ice dam blocked a river in Lijin County, Shandong Province, causing a breach and flooding more than 60 villages in Lijin and Zhanhua counties.

The conditions for freezing floods can be summarized as follows: 1. Rivers with ice age, 2. River sections flowing from lower latitudes to higher latitudes, with obvious north-south flow direction. The Yellow River in my country has freezing floods in its reaches in Ningxia and Shandong. Rivers in the Northeast will also experience freezing floods when the above conditions are met.