Auckland
SAE Ltd operates in Auckland in two capacities: as direct project engineer for standalone flood assessments and stormwater design, and as CPEng reviewing and authorising engineer for residential infill RC reports.
Regional expertise
Auckland has the most complex and most actively developed civil engineering framework in New Zealand. Auckland Council's Unitary Plan, the Auckland Stormwater Code of Practice v4 (2024), Watercare Code of Practice 2023, and the Stormwater Management Area Framework (SMAF) create a regulatory environment that differs significantly from other NZ regions.
Auckland-specific technical requirements SAE routinely applies include: TP108 SCS stormwater modelling (Ia = max 5 mm - more conservative than standard SCS), SMAF zone classification (SMAF-1 vs SMAF-2 retention/detention volumes per GD01 calculator), Watercare capacity verification, AUP E12/E27/E36/PC79 compliance, and 2D HEC-RAS flood modelling on 2024 LINZ LiDAR where Auckland Council requires it.
SAE has also published a free interactive Auckland flood map showing over 1.1 million overland flow paths derived from 2024 LiDAR at 1m resolution. Use it to check flow paths on your site before requesting a formal assessment.
Technical notes
Auckland Council requires stormwater modelling to be performed using the TP108 SCS method, which uses an initial abstraction cap of Ia = max 5 mm - more conservative than the standard SCS (λ = 0.2) or Brazilian SCS (λ = 0.05). This produces higher estimated peak flows, larger detention volumes, and more conservative flood levels than other NZ methods. All SAE Auckland stormwater designs are modelled to TP108, with NIWA HIRDS V4 rainfall data at RCP 8.5 (3.8°C) for Auckland projects.
Where Auckland Council requires a full flood hazard study as a resource consent condition, SAE produces 2D HEC-RAS models on 1 m×1 m grids using 2024 LINZ LiDAR. The Glendale Rd, Glen Eden study demonstrated overland flow paths of 0.469 m³/s and 4.28 m³/s, flood depths to 1.2 m, and included pedestrian hazard mapping as required by Auckland Council. For flood-prone Auckland infill sites, HEC-RAS flood levels determine minimum finish floor levels and may require piled foundations or raised building platforms.
Selected work
| Project | Key detail |
|---|---|
| Glendale Rd, Glen Eden | Full 2D HEC-RAS; 1 m x 1 m grid; 2024 LINZ LiDAR; OLFP1 0.469 m3/s, OLFP2 4.28 m3/s; depths to 1.2 m; pedestrian hazard mapping |
| Downing St, Glenfield | 3-lot infill; HEC-HMS; 2 x 3,700 L tanks; Auckland NDC |
| Crystal Ave, Glendene | 5-lot infill; full infrastructure; WW pump station (Lots 1-3) |
| Nigel Rd, Browns Bay | 17-lot terrace housing; individual detention tanks; deep infrastructure DTI 4.1-5.35 m |
SAE provides direct engineering services and CPEng reviewing engineer services for Auckland residential and commercial development. Enquire today.
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