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Hydroelectric plant on the São Francisco river: 2,492 anomalies mapped in three days on site
Baseline survey of a hydroelectric plant on the São Francisco river, in the state of Bahia: 11,809 photos in 33 flights, 9 orthophotos totalling 46 gigapixels, two 3D models, a virtual tour and a web interface for the operator’s engineers.
Background
The plant stands on the São Francisco river, in the state of Bahia. Its dam is of mixed design, combining concrete and rockfill. The engineering firm holding the operator’s contract entrusted us with the photogrammetric acquisition and processing: a baseline of the powerhouse, spillway, water intake and crest, to be compared in future inspections.
What we did
From 21 to 24 January 2025, after the site safety induction, two people worked with a single compact RTK drone, corrected by a permanent station of the IBGE geodetic network 3 km away. On the first day, general flights at 50 m with terrain following produced the 3D models that same evening, on which the close-range flights were computed; the drone then flew along the faces less than 4 m away, targeting 1 mm per pixel, and surveyed the galleries in 360° on the last day: 11,809 photos, 33 flights, more than 11 hours of flight, 66.5 km flown. Ten days of processing produced 9 orthophotos, from 0.85 to 3.08 mm per pixel on the faces and 8 mm on the crest, two 3D models, two modelled spillway trunnion beams and a 10-panorama virtual tour. Anomalies are classified into six types and named by zone, type and number: 2,492 in total, including 2,432 cracks totalling 2.65 km, 1,765 on the powerhouse, 581 on the spillway and 145 on the crest. The report was delivered on 18 February 2025 with a web interface, and the operator filed it in its project document system.
2 related missions in the log
First web interface delivered for a dam inspection
On 18 February 2025, with the plant report: the 9 orthophotos with their anomalies positioned, 4 3D models (powerhouse, spillway, two trunnion beams) and the virtual tour, available online for one year; a video tutorial was added after the technical meeting on 21 February.
- 9 orthophotos online
- 4 3D models
Drone inspection of a hydroelectric plant on the São Francisco river
From 21 to 24 January 2025, after the site safety induction: 11,809 photos in 33 flights and 66.5 km flown, including close-range flights less than 4 m from the faces; 9 orthophotos (46 gigapixels), two 3D models, a virtual tour and 2,492 mapped anomalies, delivered with a web interface.
- 11 809 photos
- 2 492 anomalies mapped
Gallery
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97310 Kourou
French Guiana
Route des Trois-Îlets
97229 Les Trois-Îlets
Martinique
20030-041 Rio de Janeiro – RJ
Brazil