Which units correspond to emitter discharge rate and precipitation rate, respectively?

Which units correspond to emitter discharge rate and precipitation rate, respectively?

• A. GPH or LPH; in/hr
• B. GPM; cm/day
• C. LPH; cm/hr
• D. PSI; in/cm

Answer: (A)

Emitter discharge rate is the amount of water coming out of the emitter per unit of time, so it’s expressed as volume per time. In irrigation practice, that means gallons per hour or liters per hour. Precipitation rate, on the other hand, describes how much water is applied to the ground as a depth over time, so it’s given in inches per hour (or millimeters per hour). The combination of GPH or LPH for the emitter and inches per hour for the precipitation rate matches these two distinct types of measurement, making it the correct pairing. Other options mix units that don’t fit: gallons per minute is a different time base, PSI is a pressure measure, and cm/hr is possible but the standard convention in many contexts is inches per hour.

Emitter discharge rate is the amount of water coming out of the emitter per unit of time, so it’s expressed as volume per time. In irrigation practice, that means gallons per hour or liters per hour. Precipitation rate, on the other hand, describes how much water is applied to the ground as a depth over time, so it’s given in inches per hour (or millimeters per hour). The combination of GPH or LPH for the emitter and inches per hour for the precipitation rate matches these two distinct types of measurement, making it the correct pairing. Other options mix units that don’t fit: gallons per minute is a different time base, PSI is a pressure measure, and cm/hr is possible but the standard convention in many contexts is inches per hour.