Drone Systems
Environmental
Surveys
Contactless drone surveys of rivers and streams: water surface elevation, riverbed geometry, flow velocity and discharge. Developed and tested in the EU project UAWOS, now offered as a service by Drone Systems.
Surveys without touching the water
Traditional river surveys require people in the water, a boat or access to the bank at every cross-section. Our drones measure the water surface, the bed and the flow velocity from the air with RTK precision, also where there is no path, bridge or gauging station. The result is data that can go straight into hydraulic models, checks against the watercourse regulations and flood mapping.
The methods are documented in four survey protocols (UAWOS D3.1–D3.4) and tested on rivers in Denmark, Sweden, Germany and Italy. The first commercial job was delivered to Wasserwirtschaftsamt Weilheim, on the Lech, in February 2026.
Water surface elevation
The drone follows the river with a radar altimeter and records the water surface continuously. The result is a water-level profile along the centerline with the water surface slope, ready for hydraulic modelling and water-level checks.
Spacing under 1 m · accuracy 3 cm · 10–45 m flight altitude · delivered as CSV and profile plots in your vertical datum
Datasheet (PDF)Riverbed geometry
One complete cross section from bank to bank with three sensors on the drone: LiDAR maps the banks, floodplain and the dry part of the bed as a terrain model, and below the water either a water-penetrating radar or an echosounder, chosen for the river’s conductivity and flow. All of it is merged into one cross section. The terrain model is also delivered on its own for the whole corridor.
Accuracy 10 cm above and below water · LiDAR 1–4 km of river per hour, bed 0.75–2 sections per hour · cross sections, bed points, point cloud and DTM
Datasheet (PDF)Flow velocity
A Doppler radar measures the surface velocity while the drone hovers 4 m above the water at a series of points across the section. No wading, no boat, and it can be done at high flow.
Accuracy 0.1 m/s · velocity distribution per cross section · CSV and plots
Datasheet (PDF)Discharge
Water surface slope, cross section and surface velocity are combined into an estimate of discharge and hydraulic roughness. Suited to ungauged sites, to checking rating curves, and to measuring during events.
Accuracy 15 % or better · within 3–9 % of ADCP reference on the Torne River · discharge, uncertainty and roughness per cross section
Datasheet (PDF)How we fly
By default, jobs are flown within visual line of sight (VLOS) in the open category. Longer stretches are flown beyond visual line of sight (BVLOS) under EASA PDRA-G03 with a survey drone and a relay that maintains the radio link and the overview. We received our BVLOS authorisation in August 2026, and the first BVLOS surveys have been flown on the Gudenå.
- RTK/PPK positioning
- Terrain-following flight
- Two pilots, specific category
- Relay with camera
- Own base stations and Starlink
- Data in your coordinate system
About UAWOS
UAWOS, Unmanned Airborne Water Observing System, is a Horizon Europe project (2023–2027) developing drone-borne sensors and survey methods for rivers: water surface, bed, flow velocity and discharge at high resolution, as a supplement to gauging stations and satellite data. The project is led by DTU. Drone Systems leads the work package for survey methods and provides the four services as the commercial supplier.
The methods have been field-tested on Rønne Å, the Gudenå, Torne älv, Isar, Lech and Orco, and the sensors are available from SPH Engineering. All protocols and datasets are public at uawos.dtu.dk.
Funded by the European Union, Horizon Europe, grant agreement no. 101081783.References
Wasserwirtschaftsamt Weilheim
Water surface, echo-sounder bathymetry and Doppler velocity downstream of the weir at Epfach. First commercial UAWOS survey, delivered after quality review.
First BVLOS survey
Water surface elevations on 8 km of the Gudenå flown beyond visual line of sight under PDRA-G03 with a survey drone and a relay. A second stage with Doppler cross-sections follows in November 2026.
We are always ready for a no-obligation conversation and a quote
Contact us
Sune Nielsen · sune@dronesystems.dk · +45 21 85 17 44
Contact us here