CAA-Approved Flood Risk DTMs

Drone Flood Risk & Hydraulic Surveys.

Compare quotes from specialist UK drone operators for high-resolution DTMs feeding TUFLOW / HEC-RAS, drain and culvert capacity inventories, SUDS design surveys, and rapid post-flood damage documentation.

“Every drone pilot on this network is personally vetted by me — insurance, qualifications, flight history.”

Peter Leslie · Founder & GVC Drone Pilot

Trusted by site managers & agencies across the UK

Need a flood risk survey?

Post your details to compare quotes from flood-risk specialist drone pilots.

Free LIDAR is not good enough for a 1:100 FRA.

Flood-risk consultants, drainage engineers, and loss adjusters need ground-truth topography. The Environment Agency's national LIDAR composite is a superb starting point — but not a finishing one.

Composite LIDAR Is Too Coarse

EA LIDAR Composite at 1 m or 2 m resolution is fine for catchment-scale modelling but smooths out kerb lines, low boundary walls, and garden features that absolutely govern surface-water behaviour on a single development site.

Drain & Culvert Capacity Unknown

Most local-authority culvert and gully records are incomplete or decades out of date. A drone orthomosaic with an annotated inventory fills the gap in hours, letting drainage engineers model real-world capacity, not paper capacity.

Slow, Expensive Post-Flood Adjusting

Loss adjusters and engineers arriving a week after the event find evidence already washed away. A rapid-response drone flight creates a dated, defensible record of damage extent, freeboard, and debris lines while they are still visible.

FRA deliverables have to line up with EA data.

By Peter Leslie, Founder & GVC Drone Pilot

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A flood-risk assessment is only as defensible as the topographic base it sits on. If the drone DTM doesn't tie into OSGB heights, or doesn't mesh with the EA's flood map boundaries, the modeller has to start again.

Every flood-risk survey on this network is flown by drone operators delivering DTMs in OSGB36 / ODN, co-registered to EA LIDAR, with documented accuracy and residuals. Drop it straight into TUFLOW, HEC-RAS, or InfoWorks ICM.

The result is a topographic dataset the Lead Local Flood Authority, the EA, and the developer's insurer can all agree on.

OSGB36 / ODN Aligned

PDRA01 & £5M Public Liability

Topography your hydraulic modeller can use.

Our network operators deliver survey-grade topography and evidence packs ready for FRA submission, drainage design, and insurance claims.

High-Resolution DTMs

Bare-earth DTMs at 5–10 cm GSD, supplied as GeoTIFF or LAS point cloud. Co-registered to OSGB36 / ODN so they drop straight into TUFLOW, HEC-RAS, InfoWorks ICM, or MIKE without reprojection.

Drain & Culvert Inventories

Annotated orthomosaics locating every gully, inlet, culvert headwall, and outfall across the study area. Dimensions and condition notes captured at site, feeding straight into the drainage schedule.

Post-Flood Damage Reports

Rapid-response flights capture debris lines, freeboard against fixed structures, and damage extent before evidence is lost. Dated orthomosaics and annotated reports hold up under insurer and tribunal scrutiny.

Book your flood-risk survey in 3 steps.

We connect you with the specific flood-risk and drainage specialists you need, instantly.

Describe the Catchment

Tell us the site, the purpose (FRA, drainage, SUDS, post-flood), and the modelling package the output will feed. Takes under two minutes.

Compare Specialists

We route your brief to PDRA01-holding topographic drone operators in your region. You receive competitive quotes with DTM accuracy and deliverable format.

Fly & Deliver

Your drone pilot locks in ground control, flies the catchment, and delivers DTM, contour plan, orthomosaic, and drain/culvert inventory, ODN-referenced.

Start Your Project Brief

FRAs approved, claims evidenced.

See how flood-risk consultants, drainage engineers, and loss adjusters use drone topography through our network.

"Our TUFLOW model was being choked by coarse composite LIDAR at the kerb line. Dropping in a 5 cm drone DTM for the site and 50 m beyond changed the surface-water flow paths materially — and the FRA held up at planning."

Priya S.

Flood Risk Consultant, Reading

"The drain and culvert inventory arrived as a properly attributed shapefile. Dropped into InfoWorks ICM and we were modelling real-world capacity the same afternoon. Saved easily a week of site walking."

Daniel O.

Drainage Engineer, Hull

"A drone pilot on this network mobilised inside 36 hours of a major fluvial event. The orthomosaic and freeboard measurements closed three claims we would otherwise have had to litigate. Outstanding value."

Caroline J.

Loss Adjuster, Tewkesbury

Flood Risk Survey FAQ

Technical questions on DTMs, modelling, and post-flood mobilisation.

How do drone DTMs align with EA LIDAR and flood maps?

Network operators co-register drone outputs to OSGB36 / ODN using surveyed ground control, and mesh the drone DTM into the EA National LIDAR Programme boundary so the modeller has a seamless topographic surface. Residuals between the datasets are quantified and reported.

Photogrammetry or LiDAR for hydraulic modelling?

Photogrammetry is ideal for open urban, development, and bare-earth sites. LiDAR earns its place on heavily vegetated catchments, riparian corridors, and culvert inlets where ground is obscured. Our drone operators will advise which is the right tool for your catchment as part of the quote.

Can you model a 1:100-year event from the survey?

No — drone surveys produce the topographic base, not the hydraulic model. What we deliver is a DTM, orthomosaic, and drainage inventory that drops cleanly into TUFLOW, HEC-RAS, InfoWorks ICM, or MIKE, where your flood-risk consultant runs the 1:100 and 1:1000-year scenarios.

How quickly can you mobilise after a flood event?

Rapid-response network operators target 24–72 hours for post-flood deployment subject to airspace clearance and safe flight conditions. Capturing the site while debris lines and freeboard marks are still fresh is usually decisive for the subsequent claim or tribunal.