In the flow of water through a porous soil medium, what two terms represent the total head at any point?

In the context of groundwater flow through a porous soil medium, the total head at any point is expressed as the sum of the elevation head and the pressure head.

The elevation head represents the height of the fluid above a reference point, typically measured from a datum such as sea level or the bottom of the water table. It corresponds to the potential energy of the water due to its position in the gravitational field.

The pressure head relates to the pressure exerted by the water at that point in the soil medium. It effectively indicates how much water could rise in a piezometer tube due to pressure, contributing to the total energy available for flow.

When analyzed together, these two components — the elevation head and the pressure head — provide a comprehensive measure of the energy state of water in the soil allowing for predictions about its movement in response to hydraulic gradients.

Velocity head, while relevant for calculating certain flow dynamics through a pipe or channel in fluid mechanics, is not included in determining the total head in porous media flow, hence it is excluded from the correct formulation.