FLAHAAGRI TECHDiscuss your projectFlahaCALC
methodology.
How FlahaCALC supports crop-water requirement and irrigation decision workflows using established calculation practice.
Document revision: 2026-07-20
Scope
FlahaCALC supports professional irrigation decision workflows including reference evapotranspiration, crop-water requirement framing and scheduling-oriented planning for agricultural and landscape contexts.
Purpose
Help practitioners estimate water demand and organise irrigation planning with transparent calculation context—without replacing hydraulic design or field verification.
Typical inputs
- Weather / climate inputs appropriate to the site
- Crop type and growth-stage assumptions
- Irrigation system and management context
- Soil and root-zone notes where available
Typical outputs
- Crop-water requirement estimates
- Irrigation scheduling guidance
- Water-balance oriented project views
- Traceable calculation context for technical review
Units & measurement notes
| Quantity | Typical units | Notes |
|---|---|---|
| Reference ET (ETo) | mm/day | Atmospheric demand for a reference surface. |
| Crop ET (ETc) | mm/day or mm/period | Crop-adjusted demand for the selected stage. |
| Crop coefficient (Kc) | dimensionless | Links reference ET to crop stage. |
| Irrigation requirement | mm or m³ | Planning quantity before system efficiency adjustments. |
| System efficiency / DU | % or fraction | Operational factors applied by competent operators. |
Key indicators
- Reference and crop evapotranspiration estimates
- Growth-stage coefficient assumptions
- Irrigation requirement framing
- Scheduling outlook and operational alerts
- Sensitivity to weather and crop-stage inputs
Scientific engines
- Reference evapotranspiration workflows
- Crop coefficient and crop-water requirement logic
- Irrigation requirement and water-balance framing
- Operational alert and forecast support
Calculation notes
- Workflows are designed around established crop-water calculation practice, including FAO-56 and ASCE-oriented approaches where applied to the configured use case.
- ETc is commonly framed as ETo × Kc (and related management coefficients); exact implementation details are engine-version specific and will be published with validation packages.
- Outputs are planning aids. Hydraulic design, emitter selection and control programming remain engineering responsibilities.
Standards & documentation status
Primary scientific anchors include FAO Irrigation and Drainage Paper 56 concepts and ASCE reference ET practice where configured. Full coefficient tables and site validation evidence are progressive publications.
Validation status: Public methodology: structured overview with standard anchors named. Peer-reviewed validation datasets and engine changelogs pending release.
Engine / methodology version: Public marketing methodology v0.9 (overview)
Assumptions
- Weather and crop coefficients represent the intended production system.
- System efficiency and distribution uniformity are interpreted by competent operators.
- Scheduling outputs are planning aids, not automated control authority unless separately commissioned.
Limitations
- Does not replace irrigation hydraulic engineering or licensed design.
- Does not replace soil-moisture probes, system audits or agronomic field checks.
- Results are sensitive to input quality and site assumptions.
Revision history
- 2026-07-20 — Initial public methodology stub published.
- 2026-07-20 — Added units, FAO/ASCE anchors, calculation notes and knowledge links.
Reviewer identity and peer-validation packages will be added when scientific ownership signs off formal releases (architecture §8.1).