Full site calculator

See the numbers for yourself.

Enter the site’s water levels, pipe route and diameter to estimate transfer flow and compare the stated operating assumptions.

Siphonic transfer selected

2.8 m³/minSiphonic+36 L/s vs natural fall47 L/s · 1.51 m/s · within screening — jump to results
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, starting at the intake and ending at the outlet. 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

m
200 mm internal bore · reference pipe

Your homepage estimate uses this hydraulic bore. It is not a catalogue outside diameter or a transfer-unit size.

Select a catalogue pipe to refine the estimate and request a report.

mDrives the whole transfer figure. Measure it between the intake and outlet water surfaces, not the ground.
m

Storm event

0 mm to move
ha
mm
mm
Water to move0 mm0 mm connected storm depth

Outlet & baseline

Non-tidal / free outlet
Non-tidal / free outlet
mRaises the intake water level above its normal upstream level for the temporary-stage figure.
mRaises the outlet water level above its normal level for downstream tide, storm surge or receiving drain rise.
mClassifies the gravity outlet only — free outlet, tailwater-controlled or drowned outlet.
h/daySets the daily outlet availability used for drain-time summaries only. It does not change instantaneous pipe capacity.
Advanced Settings

Pipe material

PVC SN4The calculation keeps the entered 200 mm internal diameter. Nearest catalogue reference DN175 (ID 190.4 mm). PVC SN4 catalogue size with supplier mean internal diameter where published.

Natural fall basis

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

Main assumptions

nSets the open-channel roughness the gravity calculation runs at.
mmSets the closed-pipe roughness the siphonic transfer and pump-main calculations run at.
KAllows for entry, outlet and selected route fittings. The default ΣK = 2 is a screening assumption. A separately validated loss coefficient for the transfer-unit body and internal non-return assembly is not included.
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 and exhaust drop. It uses 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

~33 joints on this route (PVC SN4, 6 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

°CSets the water viscosity and vapour pressure the calculation uses. The published matrices assume 10 °C.
mSets the atmospheric pressure behind the crest vacuum margin. The published matrices assume sea level.

Pump benchmark

%Sets the efficiency used for the pump-station energy benchmark. It is not a selected pump guarantee.
NZ$/kWhPrices the pump-station operating-cost benchmark only. It does not change hydraulic flow.

Flow window

%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
Siphon sectionParameter-driven cross-section showing terrain, water levels, pipe route, crest shape and selected drainage method. Site measurements are summarised outside the diagram.

Site screening preview

Site cross-section preview for the selected drainage method.

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 siphonic transfer estimate.

  1. Natural fallAssumed flow: 25% of full-bore reference
    0.7m³/min12 L/s · 1.25 m/s
    41× 25,000 L tanks/day
  2. Siphonic transferActively primed pressure transfer
    2.8m³/min47 L/s · 1.51 m/s · +36 L/s vs natural fall
    164× 25,000 L tanks/day
  3. Pump stationEnergy benchmark · not a pump selection
    2.66kW64 kWh/day · NZ$19/day · 24 h continuous
    2.8 m³/min47 L/s · 1.51 m/s · matched transfer target

Email me the full screening report

Receive a PDF of your screening estimate, site information and calculation assumptions. We’ll use the details below to send the report and follow up about this site enquiry.

No map view is attached. You can still request a report using your entered measurements.

Your details and report are emailed for this enquiry. No visitor account is created. Read the privacy notice.

The emailed report covers PE SDR17 pressure lines — select PE pipe in Advanced Settings to request it.

Read the Engineering ReferenceSee the calculation methods, assumptions and limits, and the basis for the reported farm figures.