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.
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.
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.
So, in 2017, Loftus and colleagues set up a group of 28 internet connected water level sensors throughout the flood risk community of Norfolk, Virginia.
Then, for three hours as the tide goes out, the water is held back within the breakwater, increasing the difference in water level, until it's several metres higher within the lagoon than in the open sea.
In Charleston, South Carolina forecasters predicted a storm surge, a rise in sea water levels, of five to eight feet higher than where the tide normally is and up to 15 inches of rain was expected there adding to the flooding.
But the fear is this isn't going to be higher ground for that much longer because even though there's no rain forecast here for the next five days, the water levels here are still rising.
While extremely high winds are expected, the main fear is a surge in sea water levels and the damage that could bring to these low lying communities when it comes ashore.