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SMAF Requirements

Have you ever worked on a project in a SMAF area and met the stormwater regulations required, but not known why those regulations are in place? We are experts on SMAF regulations and thought we would share some of our knowledge to help you understand why you have to do what you’re doing!


The Auckland Unitary Plan introduced stormwater regulations in the Auckland region including detention and retention (reuse) flow controls for sites located in SMAF (Stormwater Management Areas: Flow) areas. These areas have been identified due to the drains deemed as sensitive to changes in stormwater flows, have high natural values, and are at potential risk from an increase in the impervious area associated with future development. 


The increase of impervious surfaces from the growing rate of housing developments increases the flow rate and volume of stormwater runoff. Unless this increased stormwater runoff is managed, there would be numerous negative effects on the surrounding environment. These effects include accelerating river and stream erosion, bank instability, and creating hydrological conditions that do not support healthy aquatic ecosystems. In developed urban catchments with large areas of impervious surface, increased runoff is one of the primary causes of degraded river and stream health. SMAF regulations have been placed to protect and enhance rivers, streams and aquatic biodiversity within Auckland’s urban areas, whilst also allowing developments to continue. Detention tanks capture stormwater runoff.


Image: Blue highlighted sections represent SMAF areas within Auckland region.

SMAF areas have been divided into two different types;

  • Stormwater management area control – Flow 1 are those catchments that discharge to sensitive or high-value streams that have relatively low levels of existing impervious area. 
  • Stormwater management area control – Flow 2 areas typically discharge to streams with moderate to high values and sensitivity to stormwater, but generally with higher levels of an existing impervious area within the catchment. 


In Stormwater management area control – Flow 1 and Stormwater management area control – Flow 2, future development and redevelopment is still enabled, but it is subject to standards to reduce stormwater runoff to protect Auckland’s aquatic biodiversity and other values from further decline and enhance them where possible.

Aquacomb is the complete hidden stormwater solution for water detention and reuse (retention) to meet all of your SMAF requirements – it will save you time, space, and money too! The fully modular system isn’t just a tank. It is a clever way to capture, reuse and detain water while preventing the loss of valuable space around your development. Store them in the slab, deck, lawn, patio, JOAL, and/or driveway. Stack them on their edge under soffits, behind retaining walls, or even under stairs. Completely hidden from view, say goodbye to above-ground pipes and big, ugly water tanks that take up valuable space. Even better, Aquacomb can be installed on sites with high invert levels or where discharge to curb is required. 

Image: AquaPit Section Drawing for Combined Detention and Retention System

Laid at grade, or in-slab means they are above council pipes but still hidden. Installed in a driveway or in the slab of a house, they can still drain to a stormwater pipe with a high invert level. Being modular, the overall capacity of an average system can vary anywhere from 3,000 to 30,000 litres. Aquacomb is cost-effective and in many cases less expensive than other detention and re-use systems.


Learn more about Aquacomb here or contact our friendly team today via 0800 11 08 08

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