Ice jam flood: a lot of frazil ices and crushed ices gather under the covering ice, causing heading up of water level of upper reach.

冰塞洪，冰花与碎冰在盖面冰集聚，造成上游位显著壅高的现象。

Overpumping groundwater for drinking water and irrigation has caused water levels to decline by tens of metres in many regions, forcing people to use low-quality water for drinking.

过度抽取做为饮用和用来灌溉在许多区已经使位降了几十米，迫使人们使用质较差的来做为饮。

The resistance to float relates to the attributes and conditions of the ground water, the pressure and floatage of water, the change of water level and the sudden supplement of water.

结构抗验算与的性状、压和、位变化的影响因素、外补有关。

By fluviograph survey water level, after clear signal processing, inputs the control water level in PLC, then carries on the control by PLC to the water level control valve to adjust the water level.

由位计测位，进行信号处理后输入控制位的PLC中，然后由PLC对位控制阀进行控制以调节位。