Formula used
Applied volume: V = q × t
Estimated diameter: D = Kd × V0.35 × correction factors
Estimated depth: Z = Kz × V0.34 × correction factors
Wetted area: A = π × (D ÷ 2)2
Recommended spacing: S = D × (1 − overlap)
The model combines water volume with soil coefficients. Corrections represent moisture, slope, pressure, mulch, and placement.
How to use this calculator
- Select the calculation mode and preferred units.
- Enter emitter flow and irrigation duration.
- Choose soil texture or provide custom coefficients.
- Add moisture, root depth, slope, and spacing.
- Apply calibration when measured field data exists.
- Review warnings before changing irrigation schedules.
Start with representative soil and emitter information. Compare estimates against several field measurements before final design.
Example data
| Scenario | Soil | Flow | Runtime | Spacing | Purpose |
|---|---|---|---|---|---|
| Vegetable bed | Loam | 2 L/h | 60 minutes | 35 cm | General sizing |
| Orchard tree | Clay loam | 4 L/h | 120 minutes | 80 cm | Root-zone coverage |
| Raised bed | Sandy loam | 1 L/h | 45 minutes | 25 cm | Runoff control |
Soil reference
| Soil texture | Typical infiltration | Expected pattern |
|---|---|---|
| Sand | 25–50 mm/h | Narrower and deeper |
| Sandy loam | 12–25 mm/h | Moderately deep |
| Loam | 7–15 mm/h | Balanced spread |
| Silt loam | 5–10 mm/h | Wider spread |
| Clay loam | 3–7 mm/h | Wide and shallow |
| Clay | 1–5 mm/h | Widest surface spread |
Reference values vary with structure and compaction. Field infiltration tests give stronger design inputs.
Frequently asked questions
What is emitter wetting diameter?
It is the horizontal wetted width around an emitter. The actual boundary changes with soil and runtime.
Is the wetting pattern perfectly circular?
No, slopes and layered soils distort the pattern. Results show an equivalent average diameter.
Why does clay produce wider wetting?
Clay usually moves water sideways more strongly. Its lower infiltration can increase surface spread.
Why does sand wet deeper?
Large pores encourage faster downward water movement. Lateral spreading is often more limited.
Can this calculator size emitter spacing?
Yes, it calculates spacing from desired overlap. Field verification remains important before installation.
What does field calibration change?
Calibration aligns predictions with measured wetting diameter. It reduces local soil-model mismatch.
Does pressure affect wetting diameter?
Pressure changes emitter discharge and distribution uniformity. Compensating emitters reduce this effect.
What is pulsed irrigation?
Pulsed irrigation applies water in repeated intervals. It may improve lateral spread and infiltration.
How should mulch be handled?
Mulch reduces evaporation and surface crusting. The calculator applies a modest spread adjustment.
Can subsurface emitters be evaluated?
Yes, select the subsurface installation option. Depth and surface diameter corrections are applied.
Are these results suitable for final engineering design?
Use results for preliminary planning and comparison. Confirm performance through field tests and professional review.