It is usually measured as a water surface elevation, expressed in units of length, but represents the energy at the entrance (or bottom) of a piezometer. In an aquifer, it can be calculated from the depth to water in a piezometric well (a specialized water well), and given information of the piezometer's elevation and screen depth.
Atmospheric pressure [change]
Even though it is conventional to use gauge pressure in the calculation of hydraulic head, it is more correct to use total pressure (gauge pressure + atmospheric pressure), since this is truly what drives groundwater flow. Often detailed observations of barometric pressure are not available at each well through time, so this is often disregarded (contributing to large errors at locations where hydraulic gradients are low or the angle between wells is acute.)
Analogs to other fields [change]
- Hydraulic head is analogous to:
- A continuous "field" of hydraulic heads is analogous to:
- Similar differential operators can be applied to the fields, to find:
Other pages [change]
- Bear, J. 1972. Dynamics of Fluids in Porous Media, Dover. ISBN 0-486-65675-6.
- for other references which discuss hydraulic head in the context of hydrogeology, see that page's further reading section