What does precipitation rate indicate?

• A. The total annual rainfall
• B. The rate at which a sprinkler head applies water, typically inches per hour
• C. The soil infiltration rate
• D. The water temperature requirement

Answer: (B)

Precipitation rate is the rate at which a sprinkler head applies water to the ground, expressed as inches of water per hour. This tells you how quickly the area is being wetted, which is crucial for matching irrigation to how fast the soil can absorb water. If the rate is too high for the soil’s infiltration capability, water runs off instead of soaking in, leading to waste. So the key idea is the speed of water application from the head, not the total rainfall over a year, the soil’s infiltration limit itself, or any water temperature requirement. For example, if a head delivers about 0.5 inches of water in one hour, its precipitation rate is 0.5 inches per hour.