LiDAR SurveyPerth property mapping
Application · Flood & stormwater

Hydrologically-correct DTMs — the foundation under every flood model.

Flood models are only as defensible as the terrain they run on. Drone LiDAR captures the bare-earth surface beneath vegetation, resolves the levees, swales and creek geometry that drive flow paths, and produces the hydro-enforced DTM 1D and 2D modellers actually need — to AHD, at sub-metre resolution, across the full study area.

Interactive · AEP explorer

Step through AEP events on a real floodplain geometry.

Snap to preset AEP levels or scrub the slider. The plan view shows inundated cells against the captured terrain; the cross- section shows the water surface against floor-finished levels. Same LiDAR DTM in both — the same surface that would drive a TUFLOW or HEC-RAS run.

Water surface · 3.40 m AHD (above creek bed)Range · 010 m
Inundated area
14.1 ha
Peak depth
3.40 m
Floors over FFL
2 / 6
Cell resolution
≈ 16 × 16 m
CafeRiverside housesHousesSchoolHousesChurchTRANSECT A–A'PLAN VIEW · LIDAR DTM + WATER OVERLAY · 16 m CELLS2468101214m AHD3.40 mSECTION A–A' · TRANSECT ACROSS FLOODPLAIN

Hydrologically-correct DTM in, defensible flood map out. The same LiDAR-derived DTM that drives the 1D/2D hydraulic model drives this inundation map. Adjust the water surface to step through AEP events, or scrub the slider to see how marginal floor-finished-level decisions look in real terrain.

±50 mm
DTM vertical accuracy
Validated to AHD
1 m
Cell resolution
Standard hydro DTM
300 ha
Captured / day
Urban or rural floodplain
Yes
Under-canopy
Multi-return ground capture
The problem

Why flood models built on the wrong terrain fail expensively.

The hardest part of a flood study isn't the hydraulics — it's producing a defensible bare-earth surface to run them on. Most legacy DTM sources have problems that quietly propagate into every result the model produces.

  • 01 · Photogrammetry misses the ground under cover

    Photogrammetric DEMs over creek lines, levees and floodplain vegetation include the canopy as the surface. Flow paths get diverted, levee crests get smoothed away, and inundation maps shift in the wrong direction.

  • 02 · Government LiDAR is rarely current enough

    Open ELVIS LiDAR is invaluable as a starting point — but on a fast-changing floodplain, a five-year-old surface misses every new levee, road embankment, swale and structure that the current model needs to honour.

  • 03 · Hydro-enforcement is invisible until the model breaks

    Bridges, culverts and pipe inlets are vertical features the DTM has to represent honestly. Without explicit hydro-enforcement, the model routes flood water onto roads it physically can't reach.

  • 04 · Structure inundation lives or dies on FFL accuracy

    Floor-finished-level decisions get challenged in council and insurance. Property-level inundation calls based on a metre-resolution photogrammetric DEM rarely survive a follow-up site survey.

Why LiDAR

LiDAR makes the terrain layer the most defensible part of the model.

A drone LiDAR capture produces the hydro-DTM that 1D and 2D models need: bare earth, hydro-enforced at structures, validated to AHD, captured across the full study area to a resolution modellers can actually use.

  • Bare earth, even under canopy

    Multi-return capture and classification recover the ground beneath riparian vegetation, dense floodplain canopy and creekside scrub. Levee crests stay intact; swales stay open.

  • Hydro-enforced at every structure

    Bridges, culverts, pipe inlets and weirs explicitly resolved as breaklines in the DTM, with deck levels, soffit levels and invert levels surveyed and embedded.

  • Defensible to AHD

    Captures validated against AHD GNSS control. Every result the model produces references the same vertical datum the council, insurer and regulator expect.

  • Building footprints + FFL

    Structures captured directly from the cloud — outline, eave height, roof type — with floor-finished levels survey-validated for the structures inside the inundation envelope.

  • Post-event change detection

    Same capture, same control, after the event. Scour, breach, sedimentation and structural damage drop out as period-on-period comparisons — for FRP audit, insurance and rebuild scope.

  • Cross-checkable with public LiDAR

    Drone capture overlaid against ELVIS or state LiDAR to flag genuine change vs. acquisition difference. Lets the model author defend any departure from the public surface.

Outputs

Deliverables hydraulic modellers and flood engineers can use.

Outputs are formatted for direct use in TUFLOW, HEC-RAS, MIKE, XP-SWMM, RORB, WBNM and the GIS workflows that surround them.

GeoTIFF · ASC · LandXML
Hydrologically-correct DTM

Bare-earth surface at 0.5 – 1 m cell resolution, hydro-enforced at structures with breaklines along ridges, drains and creek thalwegs.

DWG · SHP · CSV
Hydro breakline pack

3D breaklines at every culvert, bridge, pipe inlet, weir, levee and creek edge — ready to enforce in the model terrain.

SHP · GeoJSON · CSV
Building footprint + FFL

Per-structure footprint, eave height, roof type and floor-finished level — ready for property-level inundation reporting.

GeoTIFF · SHP
Land cover / Manning's n

Land-cover raster classified from the LiDAR + ortho — feeds roughness coefficients into 2D hydraulic models.

DWG · CSV · LandXML
Cross-sections + long sections

Cross-sections at any chainage interval for 1D models, with bank stations, thalweg picks and structure deck/soffit levels annotated.

GeoTIFF · DWG · PDF
Post-event change detection

Pre/post comparison of channel geometry, levees and structures after a flood event for FRP audit, damage reporting and rebuild scope.

Workflow

A typical flood capture, end to end.

  1. 01
    Scope & control

    Confirm study area, model framework (1D vs 2D, software), hydro-enforcement extent and AHD control strategy with the flood engineer.

  2. 02
    Capture

    Single-mobilisation drone flight covering the floodplain at multi-return density. Riparian vegetation and structures captured in the same pass.

  3. 03
    Classify & enforce

    Ground classification, structure extraction, hydro breakline generation. Independent QA against control and ELVIS overlay.

  4. 04
    Deliver

    Hydro-DTM, breakline pack, building/FFL register and supporting layers — formatted for the modeller's preferred software.

Next step

Got a flood study that needs a defensible terrain layer?

We capture floodplain surfaces for flood engineers, council stormwater teams, water utilities and FRP consultants across Australia. Tell us the catchment, the modelling framework and the AEPs of interest — we'll scope a capture window and a deliverable pack the model author can build on.