piezometric altitude

...This valve controls water level in high level reservoirs to avoid overflow, without any external control system like float control etc. The valve remains completely open until the closing input is transmitted by the 3-ways piezometric altitude pilot.

...Water Detector for Wells The water detection probe is designed to indicate the production capacity of the aquifer at a given point in the water table. A free water level detector allows for measuring the level, and there are several types of piezometers. There are open piezometers that provide access to the water of a groundwater table; using a probe, this piezometer allows for measuring the piezometric level, which is the altitude or depth of the boundary between the water table and the unsaturated zone of the soil.