Which term describes the hydraulic power delivered by the pump?

• A. Water horsepower
• B. Mechanical horsepower
• C. Shaft horsepower
• D. Hydraulic horsepower

Answer: (A)

The key idea is the energy actually delivered to the water by the pump. This hydraulic power, often called water horsepower, represents how much energy per second the pump adds to the fluid as it moves and raises it. It’s determined by the flow rate and the head the pump develops, and is commonly expressed with a formula that ties flow and head to horsepower. This is distinct from the power the drive mechanism provides to the pump shaft (mechanical or shaft horsepower), which is the input energy before losses and before it becomes hydraulic power in the water. Some texts use hydraulic horsepower to mean the same idea as water horsepower, but in typical irrigation practice the term used for the power delivered to the water is water horsepower.