1. What is the Precipitation Rate Formula?

The precipitation rate (PR) formula calculates the rate at which water is applied to a given area in an irrigation system. It's a crucial measurement for Hunter irrigation system design, ensuring uniform water distribution.

2. How Does the Calculator Work?

The calculator uses the precipitation rate formula:

Where:

• \( PR \) — Precipitation rate (inches/hour)
• \( GPM \) — Gallons per minute
• \( Area \) — Area in square feet

Explanation: The constant 96.3 converts the units from GPM per square foot to inches per hour.

3. Importance of Precipitation Rate Calculation

Details: Proper precipitation rate calculation ensures efficient water use, prevents overwatering or underwatering, and helps design irrigation systems with matched precipitation rates across all zones.

4. Using the Calculator

Tips: Enter the total flow rate in gallons per minute (GPM) and the area to be irrigated in square feet. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is 96.3 used in the formula?
A: It's a conversion factor that accounts for unit changes from GPM/sq ft to inches/hour (1 gallon = 231 cubic inches, 1 hour = 60 minutes).

Q2: What are typical precipitation rates?
A: Rates vary by plant type and soil, but generally range from 0.5 to 2 inches/hour for most landscapes.

Q3: How do I determine GPM for my system?
A: Sum the GPM of all sprinkler heads that will run simultaneously in a zone, or measure flow rate directly.

Q4: Should precipitation rates be uniform across zones?
A: Ideally yes, to ensure even watering. Mixing sprinklers with different precipitation rates in the same zone can cause dry or wet spots.

Q5: How does this relate to Hunter products?
A: Hunter provides precipitation rate data for their sprinkler heads, which can be used with this formula for system design.