CASE C30 · FR ·
Rouen: drone survey of about 540 m of never-inspected underground river canals
French firm Sater used a drone to survey about 540 m of two underground river canal tunnels beneath Rouen's wholesale market. The canals had never been inspected since construction and were unsafe for divers or ROVs; data were collected in one day. Flights were limited to low-tide windows, and the source is a manufacturer article.
| Owner | Local authority (not named) |
| Provider | Sater (SARP group, Veolia) |
| Location | Rouen, France (Marché d'Intérêt National) |
| Aircraft | Flyability Elios 3 |
| Sensors | visual camera, LiDAR |
Before
Divers could not enter safely and ROVs risked being swept away or trapped; the canals had not been inspected since construction.
With drones
At the lowest tide, the drone was flown through two parallel 3 m-diameter canal tunnels from manholes, capturing video and LiDAR.
Outcomes
| Metric | Value | Basis |
|---|---|---|
| data collection | within 1 day vs several days of planning and set-up | Reported |
| coverage | about 540 m across two 3 m pipes, beyond the original scope | Reported |
Caveats & limits
- Manufacturer case study; year and owner not stated.
- Tides and rain change water levels, so flights were limited to low-tide windows; beyond line of sight the pilot navigated by camera and live point cloud.
Sources
- A drone river inspection for underground canalsFlyability Full text read
Sources checked: 2026-10-22