For council staff, infrastructure planners, and engineering reviewers.

Make room before the rain arrives.

Where a lower receiving water level exists, a primed Water Siphon keeps drawing stored water down toward it while positive head remains — making room in the network before the next event.

A Water Siphon crossing a grassed stopbank between a pond and a lower drain beneath a storm front.
Draw down stored water before rain.Lower receiving water can turn resting water levels into a route worth screening.

Tidal drainage / storm preparedness

Use lower tides to prepare for rain.

Where groundwater feeds an inland drain, lower receiving water can allow drawdown before a storm. Normal operation uses no external electrical supply; water levels, not a forecast or tide clock, determine the transfer window.

  1. Lower receiving water

    Draw down inland drains and connected groundwater while the source surface remains above the receiving water.

  2. Rising tide

    As receiving water rises, available head shrinks. At equal water-surface levels there is no head to drive forward transfer.

  3. Automatic backflow protection

    An internal non-return flap closes automatically against reverse flow. This protects against backflow through the unit, not seawater overtopping a coastal defence.

Route / ground / operating window

Check the route between source and outlet.

A closed pipe can cross a stopbank, road or rise where levels and crest limits allow. This diagram shows route and ground-risk checks—not a slope-dewatering installation.

Skip the route animation
Higher source, raised route, lower receiving waterA conceptual route plate shows positive water-level difference, a pipe crest, and a monitored slope or landslide-risk zone. It is not a survey or construction drawing.Higher source waterPipe crestSlope / landslide risk zoneClosed, primed routeLower receiving waterPositive headSECTION / CONCEPTUAL ROUTE PLATEGROUND + HYDRAULIC SCREEN
  • Water levelsCompare source and receiving surfaces at the same operating moment.
  • Crest + structureCheck vacuum margin, pipe loads, air management and transients separately.
  • Ground movementTreat slope stability, access and monitoring as engineering inputs, not visual assumptions.

A conceptual route plate shows positive water-level difference, a pipe crest, and a monitored slope or landslide-risk zone. It is not a survey or construction drawing.

  1. Water-level difference

    Positive head between intake and receiver supplies the transfer energy; it cannot be invented by the route.

  2. Crest and structure

    The high point needs vacuum, load, transient and air-management checks before any duty is promised.

  3. Slope & landslide risk management

    A route near unstable ground needs geotechnical review, access planning and a monitoring approach that fits the site.

Aerial concept view of a wetland park between South Dunedin streets, the coastal dune and the ocean.
South Dunedin · contextual concept view

Context chapter / concept stage

South Dunedin: making room in a low-lying catchment.

The South Dunedin concept at Forbury Park explores wetland storage and a constrained coastal edge as one contextual lens for storm resilience. It is a concept-stage study, not a council proposal, endorsement, consent decision or as-built design.

Use the concept to frame questions about storage, route, receiving stage and maintenance—not to infer a flood model or project commitment.

Read the South Dunedin concept chapter

Council applications

Where could this help your catchment?

Use these applications to identify sites worth investigating. Compare the available head, collection route, maintenance and whole-of-life cost with the alternatives, including pump stations.

  1. Stormwater networks

    Create room before rainfall and move water through a constrained route while the receiving level leaves positive head.

    Flood reduction and capacity need catchment modelling; consent and whole-of-life value remain site-specific.

  2. Upstream wastewater relief

    Consider this only where groundwater infiltration contributes to upstream network pressure and the water paths are separated and evidenced.

    This is not a wastewater bypass or a claim that stormwater should enter a wastewater network.

  3. Groundwater-driven slope instability

    Investigate whether groundwater collection and drawdown could help a selected unstable slope. Overseas siphon-well precedent is not proof of Water Siphon performance.

    Collection and effectiveness need geotechnical assessment. Drawdown can worsen subsidence in susceptible soils; no slip-prevention outcome is established.

  4. Coastal and tidal outfalls

    Use favourable receiving levels to drain trapped inland water, with source and outlet levels assessed across the tidal cycle.

    There is no forward transfer against adverse head. Collection, discharge conditions and maintenance still determine site fit.

One next step

See the numbers for yourself.

Bring source and receiving levels and an approximate route to the calculator. Use the result to frame an engineering discussion—not as a design or performance promise.

Before a project advances, resolve crest, structure, ground stability, water quality and approvals. The pump benchmark estimates equivalent energy; it does not select a pump.
See the numbers for yourself.
Read the Engineering ReferenceThe controlled method reference behind this screen: calculation regimes, worked limits and the evidence grade of every field figure.