How does a mainline differ from a lateral line?

The distinction between a mainline and a lateral line is essential for understanding irrigation systems. The mainline is primarily responsible for transporting water from the primary source or supply line to the various parts of the irrigation system, while lateral lines distribute that water to the individual zones or areas where it is needed.

The reason the statement about the mainline being pressurized at all times while the lateral line is only pressurized when the valve is open is accurate relates to how irrigation systems operate. The mainline consistently maintains pressure to ensure that water is readily available for distribution throughout the system. This constant pressurization ensures that when a valve for the lateral line is opened, there is an immediate supply of water ready to flow into that line.

In contrast, lateral lines are typically connected to valves that must be opened for water to flow. Therefore, they are only pressurized during the time those valves are activated. This behavior demonstrates the functional difference between the two types of lines: the mainline maintains supply pressure, while lateral lines manage distribution based on operational needs.