Saut Maman Valentin: seven survey campaigns on the banks downstream of the plant
Since October 2020, drone LiDAR and photogrammetry downstream of the hydroelectric plant on the Mana: point clouds, 3 cm orthophotos and differential plans of the islet from one campaign to the next.
Background
Voltalia operates the Saut Maman Valentin hydroelectric plant on the Mana river. Downstream of the structure, the banks and an islet change with each flood and low-water season. The operator wanted to measure these changes from year to year, with a repeatable method.
What we did
First campaign in late October 2020, at low water: LiDAR point cloud, photogrammetric point cloud, digital elevation model and orthophotos. In September 2021 the differential plan measured the footprint of the islet: 1.43 ha in 2020, 1.40 ha in 2021. Further campaigns followed after the July 2022 flood, at low water in November 2022, then in April 2023, March 2024 and 2025: 50 cm contour lines, classified point clouds, terrain and surface models, 3 cm orthophoto. Since late 2022, three points marked on the ground and measured in the NGG datum by a land surveyor, visible from the drone, have been used to register each survey. In April 2023 the comparison showed gradual erosion of the islet; in March 2024 its emerged area had increased, a sign of a lower water level than during the previous surveys. In 2025 a virtual tour of the plant was published online.
2 related missions in the log
Photos then a virtual tour of the Saut Maman Valentin hydroelectric plant
Virtual tour published online in June 2025 and hosted for the client.
Annual photogrammetric survey of the reservoir and islet
Campaign of the monitoring started in October 2020: acquisition on 11 March 2024, point cloud, terrain and surface models, 50 cm contour lines, 3 cm orthophoto and a plan of the footprints from 2020 to 2024. The emerged area of the islet increased, a sign of a lower water level than during the previous surveys.
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