What is the status of head in a system when there is no flow or pumping?

The status of head in a system when there is no flow or pumping is referred to as static head. Static head is the height of water in a system when it is at rest, and it is measured as the difference in elevation between the water level in the system and the point where the pressure is being measured, typically referred to as gauge pressure.

In this scenario, since there is no movement of water, all the energy is gravitational, and the pressure is only due to the elevation of the water column. This is essential in understanding how water systems work, as it allows operators to evaluate how much potential energy is available in the system and how high water can be pumped under static conditions.

The term dynamic head applies when water is flowing and accounts for the effects of friction and other forces acting on the water, which is not the case when the system is at rest. Variables in a water system typically refer to things that change depending on conditions like flow rate, pressure, or usage. Excessive head isn’t a recognized term in hydrodynamics, so this option does not apply in the context of head measurement. Thus, static head is the correct term for this scenario.