Hunter Irrigation Run Time Calculator

Hunter Irrigation Run Time Equation:

\[ \text{Run Time (minutes)} = \frac{ET \times PF \times 60}{PR \times 360} \]

Run Time:

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1. What is Hunter Irrigation Run Time Calculation?

The Hunter Irrigation Run Time calculation determines the optimal irrigation duration using evapotranspiration (ET), plant factor (PF), and precipitation rate (PR). This method helps optimize water usage while ensuring plants receive adequate moisture.

2. How Does the Calculator Work?

The calculator uses the Hunter equation:

\[ \text{Run Time (minutes)} = \frac{ET \times PF \times 60}{PR \times 360} \]

Where:

\( ET \) — Evapotranspiration (in/day)
\( PF \) — Plant factor (unitless)
\( PR \) — Precipitation rate (in/hr)

Explanation: The equation calculates irrigation time by considering water loss through evapotranspiration, plant water needs, and the irrigation system's water application rate.

3. Importance of Irrigation Run Time Calculation

Details: Proper irrigation run time calculation is essential for water conservation, preventing over-watering or under-watering, maintaining healthy landscapes, and reducing water bills.

4. Using the Calculator

Tips: Enter evapotranspiration in inches per day, plant factor (typically 0.5-1.0), and precipitation rate in inches per hour. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is evapotranspiration (ET)?
A: ET is the combined process of water evaporation from soil and plant surfaces and transpiration from plants. It represents the total water loss from the landscape.

Q2: How do I determine the plant factor?
A: Plant factor varies by plant type: low water use plants (0.3-0.5), moderate water use (0.5-0.7), high water use (0.7-0.9), and very high water use (0.9-1.0).

Q3: How do I measure precipitation rate?
A: Precipitation rate can be measured by placing catch cans throughout the irrigation zone and measuring water collected over a specific time period.

Q4: Should I adjust for seasonal variations?
A: Yes, ET values change seasonally. Use local ET data for your specific region and time of year for accurate calculations.

Q5: Can this calculator be used for all irrigation systems?
A: This method works for sprinkler systems. Drip irrigation may require different calculations due to different application methods.