What is the difference in elevation behind a dam and above a water treatment plant called?

The difference in elevation behind a dam and above a water treatment plant is referred to as potential energy. This is because potential energy in hydrodynamics is directly related to the elevation of water. When water is stored at a higher elevation, it possesses potential energy due to its position. This energy can be converted to kinetic energy when the water is released and allowed to flow downward, which is essential in water supply systems where water flows from a high point (the dam) to a lower point (the treatment plant).

In this context, it’s important to recognize that potential energy is fundamental to understanding how gravitational force acts on the water body. The higher the water is stored, the more potential energy it contains, which can then be utilized in various operations, such as generating hydroelectric power or facilitating water distribution through gravity-fed systems.

This concept does not pertain to pressure head, which is a measure of the pressure exerted by a fluid due to its weight, nor does it directly concern kinetic energy, which involves the energy of motion. Dynamic head combines both pressure and elevation, but the specific aspect of elevation alone relates to potential energy. This distinction is vital in water resources management and engineering.