Full site calculator

See the numbers for yourself.

Start with the site, not the sector. The same pressure-pipe calculation screens farm groundwater, storm resilience and constrained infrastructure routes.

Water Siphon selected

6.5 m³/minWater Siphon+81 L/s vs natural fall109 L/s · 1.81 m/s · within screeningSite name or location

Find the route on a mapOptional — NZ address search and route sketch

Search a New Zealand address, then click along the intended pipe route on the map — intake first, outlet last. Every value the map fills lands in an ordinary editable input.

Click the map to drop route points along the pipe line: intake first (cream marker), outlet last (amber marker). No mouse? Pan and zoom the map, then use “Add point at map centre” — the crosshair marks where it lands.

Drawn route length: 0 m · 0 points

Add at least two route points before checking the profile.

The water-level difference is never taken from the map — ground elevation is not water level. Measure the two water surfaces on site.

Site setup

Pipe lengthm

Pipe diametermmThe calculation uses the 277.1 mm internal diameter of catalogue OD315.

Water-level differencemDrives the whole transfer figure. Measure it between the intake and outlet water surfaces, not the ground.

Crest / obstacle heightm

Storm event

0 mm to move

Site sizeha

Rainfall total for eventmm

Soil absorptionmm

Water to move0 mm0 mm connected storm depth

Outlet & baseline

Non-tidal / free outlet

Outlet conditionNon-tidal / free outlet

Floodwater rise at intakemRaises the intake water level above its normal upstream level for the temporary-stage figure.

Outlet water risemRaises the outlet water level above its normal level for downstream tide, storm surge or receiving drain rise.

Downstream depth above outlet invertmClassifies the gravity outlet only — free outlet, tailwater-controlled or drowned outlet.

Active flow hours per dayh/daySets the daily outlet availability used for drain-time summaries only; it does not change instantaneous pipe capacity.

Advanced Settings

Pipe material

Pipe materialPE SDR17The calculation keeps the entered 277.1 mm internal diameter; nearest catalogue reference OD315 (ID 277.1 mm). PE100 SDR17 / PN10 catalogue OD with supplier mean internal diameter.

Natural fall basis

Sets the partial-pipe basis this figure is computed on; full bore stays reference-only.

Main assumptions

Gravity roughnessnSets the open-channel roughness the gravity calculation runs at.

Pressure-pipe roughnessmmSets the closed-pipe roughness the Water Siphon and pump-main calculations run at.

Minor losses ΣKKCharges the calculation a minor-loss allowance for entries, outlets, bends, valves, fittings, screens, transitions and manifold effects. Typical installations sit in the 2–4 band.

Estimate ΣK from the routeEstimated ΣK: K = 3.92

Decomposes the minor-loss allowance from the canonical siphon geometry — intake drop, up-line, crest, down-line, exhaust drop — using large-bore flanged loss coefficients.

1 × Submerged intake entranceK 0.50
2 × Intake riser bends (90° long-radius)K 0.56
2 × Up-line grade bends (≤45° sweep)K 0.40
2 × Down-line grade bends (≤45° sweep)K 0.40
2 × Exhaust riser bends (90° long-radius)K 0.56
2 × Gear-driven butterfly isolation valves (open)K 0.50
1 × Submerged outlet exitK 1.00

~16 joints on this route (PE SDR17, 12 m lengths) — joint effects are covered by the clean-pipe roughness basis and are not separately charged.

The Manifold body and its internal non-return valve are not separately modelled in this estimate.

Natural fall1.0%Derived by the calculation from the water-level difference divided by the pipe length; the default 2.0 m difference over 200 m is 1.0%.

Site conditions

Water temperature°CSets the water viscosity and vapour pressure the calculation uses; the published matrices assume 10 °C.

Site altitudemSets the atmospheric pressure behind the crest vacuum margin; the published matrices assume sea level.

Pump benchmark

Electric pump efficiency%Sets the efficiency used for the pump-station energy benchmark; it is not a selected pump guarantee.

Electricity priceNZ$/kWhPrices the pump-station operating-cost benchmark only; it does not change hydraulic flow.

Flow window

Duty factor%Reduces the available flow window for interruptions such as maintenance, tide gates or site operating limits; it affects drain-time summaries only.

Operating comparison

At your current site inputs

Outlet may sit below tailwater — submerged discharge is compatible with a primed closed pipe

Steady-state screening estimates for a fully primed closed pipe. The pump row is an energy benchmark, not a pump selection.

The emailed screening report carries the full calculation basis behind its own Water Siphon estimate.

Natural fall25% pipe-flow basis
1.7m³/min28 L/s · 1.56 m/s
98× 25,000 L tanks/day
Water SiphonActively primed pressure transfer
6.5m³/min109 L/s · 1.81 m/s · +81 L/s vs natural fall
377× 25,000 L tanks/day
Pump stationEnergy benchmark · not a pump selection
6.11kW147 kWh/day · NZ$44/day · 24 h continuous
6.5 m³/min109 L/s · 1.81 m/s · matched transfer target

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