What it does

Irrigation Layout Designer is an interactive screening workspace for a rectangular drip-irrigation block. It draws a scaled SVG schematic and estimates simultaneous flow, mainline and submain velocity, Hazen–Williams head loss, pressure margin and a simple pressure-variation-based uniformity indicator.

Preliminary design only

The calculator simplifies emitter behaviour, lateral losses, fittings, transients and terrain. Confirm a final layout with field measurements, manufacturer data and a qualified irrigation engineer.

Before you start

• Measure the block length, width, row orientation and representative slopes.
• Gather pump pressure and flow rating, filter loss, pipe diameters and emitter specifications.
• Decide whether the scenario assumes a ring main, two-side-fed submains or pressure-compensating emitters.
• Treat all displayed values as one comparative scenario, not a construction specification.

Quick workflow

1. In Field & Terrain, enter dimensions, orientation and slopes.
2. In Headworks & Constraints, set pump pressure, maximum flow, filter loss, fertigation, allowable pressure variation and maximum velocity.
3. Configure Mainline, Submains and Drip laterals.
4. Review Layout preview, Hydraulic summary and Constraint checks as values update.
5. Select Export SVG to save the current schematic.
6. Select Reset or Reset defaults to restore the initial scenario.

Controls & outputs

Group	Inputs or outputs
Field & Terrain	Length, width, clockwise orientation from north, lengthwise slope and cross-field slope.
Headworks & Constraints	Pump pressure, pump flow rating, filter loss, fixed 5 kPa fertigation loss toggle, allowable ΔP and velocity limit.
Mainline	Diameter, hydraulic length, PE (C≈140) or PVC (C≈150), edge or centreline display, and ring/two-end feed.
Submains	Spacing, diameter, two-side feed and a Valve every (runs) planning value.
Drip laterals	Tape spacing, emitter spacing, emitter flow, operating pressure, tape length and pressure-compensating label.
Layout preview	Scaled SVG schematic with headworks, mainline, submains and laterals.
Hydraulic summary	Total laterals, system flow, main/submain velocities and head losses, available pressure, pump pressure and estimated CU.
Constraint checks	Warnings for mainline velocity, pump flow, non-positive post-main pressure, negative lateral pressure margin and large slope head differences.

Valve every (runs) and the pressure-compensating toggle are recorded in the scenario but do not currently change the geometry or hydraulic equations.

How it works

Layout and demand

• Submain and lateral counts are derived with floor-based spacing rules and a minimum of one run.
• Emitters per tape are estimated from configured tape length and emitter spacing.
• System flow assumes every derived tape operates at the same time and every emitter supplies the entered nominal flow.
• Orientation rotates the local SVG geometry; it does not georeference the drawing.

Hydraulic estimate

Mainline and submain friction use:

hf = 10.67 × L × Q^1.852 / (C^1.852 × d^4.87)
v  = Q / (π × d² / 4)

The mainline uses the selected material coefficient. The submain uses C=140. Ring feed halves effective mainline length and flow; two-side feed halves effective submain length and flow.

Available lateral pressure subtracts filter loss, the optional 5 kPa fertigation loss, mainline loss, submain loss and positive lengthwise slope head from pump pressure. Cross-field slope is reported as a warning but is not deducted from the displayed available pressure.

The displayed CU is a bounded heuristic:

estimated CU = clamp(100 − 1.6 × allowable ΔP, 60, 98)

It is not calculated from simulated emitter discharge measurements.

Data, privacy & external services

All inputs, calculations and SVG generation run locally in the browser. The app does not upload the design or call a hydraulic service. Settings last only for the current page session unless the SVG is exported.

Limitations

• Lateral friction, local fittings, valves, filter curves, elevation profiles, pressure transients and water hammer are not modelled.
• Nominal emitter flow is not adjusted through a pressure–discharge curve.
• The cross-field slope, valve frequency and pressure-compensating toggle do not alter the pressure calculation.
• Only mainline velocity is compared with the entered velocity limit.
• Tape length affects demand and lengthwise slope, while laterals in the schematic span the displayed field block.
• The SVG has no geographic coordinates and should not be treated as CAD, GIS or an installation drawing.

Troubleshooting

Problem	What to check
System flow exceeds the pump rating	Reduce simultaneous laterals or emitter flow, or evaluate zoning and a different pump scenario.
Pressure margin is negative	Increase available pressure, reduce losses, upsize pipes, shorten runs or compare ring/two-side feed.
Mainline velocity warning appears	Increase mainline diameter or reduce simultaneous flow.
The CU value seems unexpected	It is derived only from Allowable ΔP (%) and is not a network simulation.
The drawing is clipped after rotation	Try a smaller orientation angle for inspection; the export uses the same fixed SVG canvas.
SVG does not download	Allow browser downloads and try Export SVG again.

Open Irrigation Layout Designer

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