What is the role of a control valve in an irrigation zone?

• A. It opens and closes to regulate water flow to the zone, in response to a controller signal.
• B. It stores water for the zone.
• C. It measures soil moisture and adjusts flow.
• D. It powers the controller.

Answer: (A)

The control valve acts as the gate for water entering a irrigation zone, opening and closing in response to a signal from the controller. When the controller commands a zone to run, the valve opens so water can flow through to the emitters; when watering is finished, it closes to stop flow. This gating function is what lets different zones be watered on different schedules without flooding the system. The other ideas don’t fit because storing water is the job of a reservoir or tank, measuring soil moisture is done by sensors, and powering the controller comes from a power supply or transformer, not the valve itself.