#08 | What is a piezometer? Importance, types and uses

Author: Eva Mena (EMUASA)

A piezometer is an instrument used to measure the pressure of groundwater, in dams, pipes, and other conduits, allowing its properties to be monitored and controlled when faced with an excavation, borehole, or drainage. It is an essential tool to carry out this type of work with safety and precision. There are several types of piezometers, although two are the most used: the open tube and the vibrating wire.

With the open tube piezometer, the pressure is measured from the surface through a depth indicator. It is somewhat similar in operation to the pressure gauge, so it is not as accurate as other mechanisms. The vibrating wire piezometer provides greater measurement accuracy and is based on the vibration frequency, which will be proportional to the water pressure. This technique allows for more precise control of pressure changes in the water, caused naturally or by our work.

This instrument can vary its aesthetics and function depending on the service it offers. There are different types of piezometers, the main ones being vibrating wire and open tube.

  • Open tube: Its main function is to measure the underground pressure from the surface. To do this they use a depth indicator from the ground which is inserted through a small hole. In this way, the precision of the result is lower than that of other types.
  • Vibrating wire: for the measurement of underground pressure, this model is based on the vibration frequency. This mechanism is based on the proportionality of the vibration frequency with the water pressure. It is done through a perforation through which the instrument is inserted, which is guided by a rope. This model offers greater precision in its results compared to other methods thanks to the mobility of the rope.

The Municipal Water and Sanitation Company of Murcia, S.A. (EMUASA) carries out an exhaustive control of groundwater, with a large number of control piezometers, as well as boreholes. Having in the Municipality of Murcia an Urban Irrigation network, for the use of watering gardens, cleaning roads and other ornamental and sports. Said network is made up of a set of boreholes, lifting installations, tanks and general networks of pipes for the distribution and supply of groundwater.

Groundwater is controlled through piezometers, regularly through the Quality Control Program, an analytical control to prevent possible sources of contamination, checking that its characteristics are suitable for the use for which it is intended.

Analytical control is set to:

  • Keep the water produced in the operating wells characterized.
  • Control the effectiveness of the treatments carried out on the water (filtration and disinfection with UV radiation).
  • Establish control against legionellosis, both in the boreholes and in the irrigation network. Understanding this as the pipes that transport water from the wells to the gardens.
  • Control the level of disinfectant and the pH of the water in the ornamental fountains.
  • Control against legionellosis in ornamental fountains.