The Tree Nurturing System (TNS™) is distributed subsurface retention that removes surface water where pits and pipes can’t.
With the ponding goes the hazard, the mosquitoes and the complaints.
Consistent with AustRoads limits on standing water in traffickable zones.
On a site designed around the system, distributed nodes take the place of an outfall main and a centralised basin. The design removes the pumps, the single point of failure and the basin’s claim on public open space.
The TNS™ provides retention, storage and passive irrigation. It is recorded as a retention asset and is not part of the minor drainage system – not a treatment device, and not an infiltration system where the node is lined. In device-type terms it is a water wise street tree, which is the category the regional stormwater quality guidance already names as an accepted device. Cleaning is carried out to keep water passing through the asset. The maintenance program →
Gross debris is excluded at the kerb line and never enters the structure. Monitoring flags a node before it blocks, and the deviation sets the response – sweeping, then pressure cleaning the tray, then filter replacement.
You aren’t inheriting an asset nobody knows how to service.
Passive irrigation to the root zone, structural soil cells sized to the mature tree – canopy retention without reticulated irrigation or water trucks.
Resolving drainage constraints unlocks adjacent land, often at no cost to Council.
A whole-of-life servicing cost comparison against a centralised basin is prepared for the project.
The approval conversation and the funding conversation are different conversations, with different officers. This section takes the funding conversation and walks the node through the nine steps of the asset management planning framework. The framework is set out in the Green Infrastructure Management Manual published by the Institute of Public Works Engineering Australasia (IPWEA).
Why the register entry has to span both. With canopy policy in parks and drainage in engineering, the street tree falls through the gap between the two teams. SA HB 214:2023 Urban Green Infrastructure – Planning and decision framework, a Standards Australia handbook, asks at Clause 3.3.9 that green infrastructure be expanded with no net loss. At Clause 3.3.6 the handbook asks that green infrastructure be integrated with the water systems that sustain it. A council pursuing a canopy target under a strategy with no water in it misses Clause 3.3.6, and through it Clause 3.3.9. Both documents are references for planning and managing green infrastructure, with no certification role. The TNS™ has no endorsement from Standards Australia or from IPWEA.
There are two entries, at two levels: the node is recorded as a hybrid green infrastructure asset; the EnviroKerb® units and EnviroKerb Tray Inlet (ETI) trays are recorded as engineered components supporting it. Under the manual’s own reporting groupings both belong on the asset register. Components carry their own lifecycle – tree, soil cell, tank module, kerb unit, tray, filter.
Canopy cover and tree survival, retention volume delivered, and the response time on a flagged node. The technical level of service sits under a community level of service the ward can actually recognise – a street that is shaded and does not flood.
The node reports on itself, with performance read from monitoring data per node rather than reconstructed from an annual inspection round.
Environmental sustainability and climate change are the two demand drivers the manual names for green infrastructure. Both move the same way for canopy and for retention, in the present and projected.
A tiered maintenance response: sweep, pressure clean the tray, replace the filter, replace the module. The unit of renewal is a single module, not a length of street – so renewal is granular and can be scheduled against condition.
The node takes a risk register entry alongside its asset register entry. Distributed nodes carry no single point of failure, which is a materially different consequence rating from one basin or one outfall main.
A green asset can be carried at replacement cost, amenity value or ecosystem services value – the manual sets out the options and the recognition tests. Capital cost lands at establishment; operating cost is known by tier.
Hybrid green infrastructure assets and the engineered assets that support them are both long-term financial plan inclusions under the manual’s reporting groupings. Step 08 turns a canopy target into a funded line.
Per-node data is the evidence an asset management plan for green infrastructure normally lacks. It is also what lifts asset management maturity on the next review.
Maintenance is a street sweeper on the rounds the street already gets, per PPCA-OM-001 Rev B, with the filter element replaced by removal. Matter SensAI measures intake against a calibrated baseline at every node and flags an inspection when intake drops, well before a blockage forms.
Where the drainage network has been designed on the reduced flows, the maintenance schedule and the monitoring are put to council at pre-lodgement with the model.
Each node serves the smallest contributing area that is practicable, which keeps runoff from being gathered up and carried elsewhere to be dealt with. Small volumes held at the kerb line are easier to handle than one large volume at the bottom of the hill. The storage also arrives with the street, in place of a separate structure on land that could have served another use.
A centralised basin takes land, takes capital, and carries a whole-of-life cost that council carries after handover. Distributed nodes take none of that land, with the monitoring telling council which node needs attention without an inspection round to find it.
On the register entry, and the order it is made in. The drainage register entry, which reads stormwater quantity asset, comes first and stays. The green infrastructure classification sits over it as evidence of multiple function, for the asset management and valuation conversation and not the assessment one. Led with on its own, green infrastructure invites an assessor to read the node as a landscape asset, which takes the trunk stormwater function off the table. Within that entry there are two levels: the node is the hybrid green infrastructure asset, and the EnviroKerb® units and ETI trays are engineered components supporting it. The manual already models a complex asset this way, with components carrying their own lifespans and maintenance regimes.
We’ll map the nodes, size the storage and set out the maintenance regime and costings.
Arrange a briefing