Site input
We start from polygons (boundary, exclusions), tap location, water source pressure and flow, soil class, slope, and existing infrastructure imported from DXF or sketched by hand.
- → DSTU Б В.2.5-22 §4.1
- → SCS Soil Survey Geographic
§ 01 · METHOD · 7 STAGES · 5 STANDARDS
How we compute.
02
Pipeline · seven stages
flow
Agronomy
Crop coefficients, root depth, ETo from Penman–Monteith FAO-56, effective rainfall, and target irrigation efficiency drive the weekly water budget per zone.
- → FAO-56
- → Allen et al. 1998
Layout
Heads are placed on a triangular grid sized to manufacturer radius. Arcs respect boundary geometry. Coverage uniformity is solved with overlap targeting CU ≥ 85%.
- → Hunter Design Manual
- → Rain Bird LDM
Hydraulics
Hazen–Williams pressure loss is computed for every pipe segment. We pick PE100 diameters that keep velocity in 1.2–1.8 m/s and end-pressure within ±10% of head spec.
- → Hazen 1905
- → PE100 ISO 4427
Zoning
Heads are grouped into zones whose total flow fits the source minus losses. Cycle-and-soak is applied where infiltration rate is below precipitation rate.
- → ASABE EP456
Bill of materials
Every head, valve, fitting, pipe meter, controller and sensor is enumerated against the multi-vendor catalog (Hunter, Rain Bird, Toro, Gardena) with current unit prices.
- → ETIM 8.0 catalog
Output
Plan PDF (DSTU 3008-95 title block), zone schedule, BoM CSV, controller programming sheet, and JSON export ready for hand-off or import into a controller.
- → DSTU 3008-95
- → ISO 5457:1999
03
Core equations · four pillars
math
Penman–Monteith FAO-56
Daily reference evapotranspiration ETo from weather data — base input for water demand.
// Formula
ETo = (0.408·Δ·(R_n − G) + γ·(900/(T+273))·u₂·(e_s−e_a)) / (Δ + γ·(1+0.34·u₂))
Δ — slope of saturation vapour pressure curve [kPa/°C] R_n — net radiation at the crop surface [MJ/m²/day] G — soil heat flux density [MJ/m²/day] γ — psychrometric constant [kPa/°C] T — mean daily air temperature [°C] u₂ — wind speed at 2 m height [m/s] e_s, e_a — saturation and actual vapour pressure [kPa]
Hazen–Williams
Pressure loss in pressurized pipe segments under turbulent flow.
// Formula
h_f = 10.67 · L · Q^1.852 / (C^1.852 · d^4.87)
h_f — head loss [m] L — pipe length [m] Q — flow rate [m³/s] C — roughness coefficient (PE100=150, PVC=145, steel=100) d — internal diameter [m]
Christiansen Uniformity
Irrigation uniformity from a grid of measured doses; ASABE S441 baseline.
// Formula
CU = 100 · (1 − Σ|x_i − x̄| / (n · x̄))
x_i — measured dose at point i x̄ — mean dose across all points n — number of measurement points
Continuity (Velocity)
Pipe flow velocity sanity check — keeps water hammer and sedimentation in bounds.
// Formula
v = 4·Q / (π·d²)
v — flow velocity [m/s] Q — flow rate [m³/s] d — internal diameter [m]
04
Standards we cite
refs
| Code | Body | Scope | Used in | Status |
|---|---|---|---|---|
| ASABE S441 | American Society of ABE | Sprinkler distribution uniformity testing | CU/DU calculation | active |
| ASABE EP456 | — | Test procedure for sprinkler heads | head spec validation | active |
| FAO-56 | Food and Agriculture Org | Crop evapotranspiration guidelines | ETo computation | active |
| EN 13742 | CEN (Europe) | Landscape irrigation systems | EU procurement | active |
| AFNOR NF U54 | AFNOR (France) | Système d'arrosage | FR/BE locale | active |
| ДСТУ Б В.2.5-22 | UkrNDIBV | Внутрішнє водопостачання | UA gov projects | active |
| ДСТУ 3008-95 | — | Title block layout | PDF export | active |
| ISO 5457:1999 | ISO TC 10 | Technical drawing sizes | PDF export | active |
| SCS Soil Survey | USDA | Soil infiltration classes | soil DB | reference |
| ETIM 8.0 | ETIM Int. | Construction product taxonomy | BoM catalog | beta |
05
Validation · regression tests
v&v
How we verify the math.
Every release ships only after a regression run against 47 reference projects — public plans with measured CU/DU/PR values. Sources include manufacturer test rigs (Hunter Marketing Office), university labs (Texas A&M Turfgrass Lab, IRSTEA Antibes), and our own field trials in Shabo and Zakarpattia.
47
reference projects
203
catch-can sites
12
climate zones
0.92
CU correlation r²
±3.2%
pressure RMSE
98.4%
BoM cost accuracy
§ 99 · NEXT