Ecology
Roof rainwater collection
Estimate collected rainfall from a roof’s horizontal catchment area and an assumed efficiency.
Calculators / Ecology / Irrigation run time
Irrigation run time calculator
Estimate irrigation duration from target depth, area, system flow and assumed efficiency.
On this page
Net water volume500L
Gross water volume625L
Run time31.25min
Calculator controls
How to calculate
Estimate irrigation duration from target depth, area, system flow and assumed efficiency.
Net water volume =
A*d LGross water volume =
A*d*100/eff LRun time =
A*d*100/eff/q minWorked example
- Watered area (m²): 50
- Required net water depth (mm): 10
- System flow (L/min): 20
- Application efficiency (%): 80
- Net water volume: 500 L
- Gross water volume: 625 L
- Run time: 31.25 min
Assumptions and limits
Efficiency must be above zero and no more than 100%. Rainfall, runoff limits, soil storage and plant water demand must be assessed separately.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Estimate irrigation duration from target depth, area, system flow and assumed efficiency. One millimetre over one square metre is one litre. Use the combined measured flow for the zone being watered.
When this tool is useful
One millimetre over one square metre is one litre. Use the combined measured flow for the zone being watered.
Understanding your inputs
| Input | Example |
|---|---|
Watered area (m²) A | 50 |
Required net water depth (mm) d | 10 |
System flow (L/min) q | 20 |
Application efficiency (%) eff | 80 |
Frequently asked questions
What does this model leave out?
Efficiency must be above zero and no more than 100%. Rainfall, runoff limits, soil storage and plant water demand must be assessed separately.
How do I reproduce the example?
Enter the displayed example values in their labelled units. Apply the formula before rounding; change one input at a time to compare scenarios.