ABSTRACT
In a Dynamic Water System, where water is flowing, the piezometric surface varies. The Hydraulic Grade Line slopes downward along the length of pipe, showing a loss of pressure energy. Pressure at a given point originates from the height, or depth of water above it. It is this pressure, or head, which gives the water energy, and causes it to flow. The components of pressure are: pressure head, elevation head, velocity head and total head. If head losses are suddenly increased, this will cause pressure to drop and then less flow will enter the entire pipe system; but once it has entered, it must exit at the same flow rate. For simple hydraulic situations, such as two points which differ in elevation alone, a quick sketch of the system allows mental calculation for the unknown. The solution would work out just as accurately if all values were inserted into Bernoulli's formula, but this is not always necessary.
