FloodMap.nz is a data product of SAE Ltd, Napier. The aim is straightforward: a consistent national overland flow path layer at the resolution councils, engineers and developers actually need — built on current LiDAR, with the sources and limitations open to inspection.
The gap that needed filling. Every consent application for subdivision, multi-unit residential, or non-trivial earthworks needs an answer to one question: where does surface water flow across this site? In practice, the answer comes from a patchwork — old council GIS layers, district plan overlays, NIWA national products, and a lot of judgement.
The new National Flood Map (Earth Sciences NZ) is excellent at the regional scale, but it covers 256 major floodplains and explicitly excludes property-level detail. Many council overland flow layers were built on 2016 or older LiDAR, and many councils don't model overland flow at all — only big rivers. That's fine for public awareness. It's not enough for an engineer trying to screen a site quickly.
How it started. Andre Magdich has done subdivision and stormwater engineering across Hawke's Bay, Manawatu and Auckland for more than 15 years, now through SAE Ltd, with 300+ projects delivered. Every one of those projects starts with the same exercise: pull the LiDAR, look at where water flows, decide what the constraints are. That work was being done one site at a time. By late 2024, with LINZ's nationwide 1 m LiDAR coverage well advanced and open-source geospatial tooling having matured, it became viable to do the analysis once, for the whole country, and publish the result.
The first region (Auckland) went live in early 2026, derived from the latest LiDAR available for that region. Every region LINZ has flown is now built and published; new areas are added as LINZ releases further survey blocks. Data sources, tier thresholds and limitations are published at /methodology.
What's published today. The public map shows overland flow paths in five tiers, from major rivers (over 5,000 ha catchment) down to small flow paths under 2 ha, plus potential ponding areas. Since October 2026, 20 council areas are mapped on a native 1 m grid. Flow paths and ponding only: no depth or hazard category. It's a screening reference, not a regulatory hazard layer. Free to view, no login, because property-level overland flow visibility is, in our view, public information.
What's coming. Native 1 m detail for more council areas, and data partnerships with councils that want closer integration. Site-specific HEC-RAS 2D flood assessments (depth, velocity, hazard) are currently delivered as bespoke engineering through SAE Ltd — see /flood-report for what those typically cover.
Chartered Professional Engineer, Director of SAE Ltd, based in Napier. Previously Design Engineer at Hawke's Bay Regional Council on flood protection infrastructure — including the Taradale Stopbank, which was tested by Cyclone Gabrielle in 2023 and did not overtop. SAE Ltd specialises in subdivision engineering, stormwater design, flood assessment and three waters infrastructure across Hawke's Bay, Manawatu and Auckland.
Data sources, tier thresholds and limitations are documented at /methodology. If a council, peer reviewer or consultant disagrees with an output, tell us and we will check it.
Built against the latest LINZ composite. As new survey blocks are published, affected regions are reprocessed. No region runs on stale terrain longer than necessary.
The OFP layer is bare-earth-derived. It does not model culverts, stormwater pipes, or constructed drainage, and it does not include depth, velocity or hazard category. It is a screening reference, not a regulatory layer. The methodology page lists every limitation up front.
Tier thresholds reference NZS 4404 and the AUP E36 4,000 m² trigger, so the layer reads the way engineers already work. It stays a screening reference: anything going into a consent needs a site-specific assessment.
The map view is and will remain free for public, professional and council use. Property-level flow visibility is too important to gate.
FloodMap.nz is built and maintained by SAE Ltd. SAE delivers civil engineering for subdivision, stormwater, flood assessment and three waters across New Zealand. Site-specific flood modelling that goes beyond the published OFP layer — HEC-RAS 2D, hydraulic neutrality assessments, consent-grade reports — is commissioned through SAE.
Methodology questions, data discrepancies, council partnership enquiries, media — direct line to Andre.
Get in touch → Read the methodology