Key Irrigation Definitions
A comprehensive glossary of essential terms for the Texas Irrigator exam, covering pressure, flow, velocity, and more.
Static Pressure
The pressure of water at rest.
Static pressure is affected by elevation change or by the force of a pump. For each 1 ft. of elevation change, static pressure (or dynamic pressure) changes by 0.433 PSI.
Dynamic Pressure
The pressure of water in motion.
Dynamic pressure is affected by changes in pressure caused by either elevation change or a pump, as well as by friction losses in pipe, valves, and fittings.
Velocity
The speed at which water is moving.
Flow
The quantity of water moving through the system.
Flow is affected by: (a) the pressure available at the source, (b) the pressure losses from the source to the outlet or outlets, and (c) the size or number of outlet(s).
Friction Loss
A term used to identify pressure losses caused by water turbulence.
Friction loss is affected by: (a) velocity, (b) pipe inside diameter, (c) roughness of the inside of the pipe, and (d) length of the pipe.
Velocity Head
The amount of pressure required to generate a specific velocity. This is the amount of energy or pressure that is used to make the water move at a given velocity.