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For developers

Unlock constrained land. Increase yield. Cut civil costs.

The TNS is a subsurface retention and passive-irrigation asset that removes runoff from the surface network – displacing detention basins and outfall drainage.

Unlock sites you can’t currently develop

Surface ponding and flood-immunity constraints on access and egress resolved without importing fill.

Displaces detention basins and outfall mains

Distributed storage in the road reserve in place of a centralised basin and a long outfall – no pumps.

Higher yield

Land recovered from detention can lift lot yield by up to ~4%.

Frequent flow objectives, met by retention

Sized to deliver the runoff volume reduction the code asks for, with flow monitoring providing the record.

Infrastructure charges

Where works are dedicated as a council asset, we pursue the trunk stormwater function argument. Positions confirmed in writing with the clause named, before anything is relied on.

Sells better

Cooler, greener streets, and a better flood status on search reports.

Where a development also carries stormwater quality obligations, those are met by separate, appropriately certified measures. We’ll model your site before you commit.

The economics

The cost case is what it displaces.

Retention at the source takes conventional infrastructure out of the civil scope rather than adding a new asset alongside it. That is where the money moves – and because it moves differently on every layout, we cost it against your site rather than quoting a rate.

01

What comes out of the scope

The detention basin, the outfall main that serves it, and the pump station where levels demand one. Where a basin is no longer required, the land it occupied returns to the developable area.

02

What replaces it

Modular storage in the road reserve, installed with the kerb and pavement works – inside the civil program and the same trades, not a separate package with its own mobilisation.

03

What it costs to hold

Servicing is surface work on plant the asset owner already operates: sweeping, a removable tray, a consumable filter, no confined-space entry. The maintenance case →

We cost it for your site, not from a rate card. The per-lot comparison against centralised detention and outfall drainage is prepared on your actual layout – your catchments, your civil scope, your plant rates – and it comes with the feasibility assessment. A published figure would not survive the variation between sites.

For developers

Tell us the site and the constraint.

We’ll model your site before you commit, and show what the retention approach recovers in developable land.

Request a site feasibility assessment