Multibeam and single beam bathymetry
Bathymetry enables topographic measurements to be taken of submerged areas of lakes, réservoirs and watercourses.
This information is essential in a number of areas such as hydroelectricity (aggradation, storage capacity and functionality of the production equipment), environment (protection against flooding) and safety (navigable waterways, sub-lake instabilities).
In this context, multibeam technology opens up new perspectives. This procedure enables to carry out continuous, geo-referenced and high resolution scans of the reservoir’s ground in a very short execution time. The quality and precision of the measurements enables an accurate reproduction of the topographic and geometric structure of the reservoir. In fact, a more realistic monitoring of overall silting evolution is possible. Furthermore, the level of aggradation around the production and/or safety equipment can be accurately recorded, thus contributing towards better anticipation of any maintenance activities required and ensuring the longevity of the installation regarding this phenomenon. This technology is installed on a small heliportable boat. It can be deployed on all lakes even those where access is limited.
The « traditional » single beam method is still used for small lakes, shallow water measurements (from 20 cm) and/or in faster currents. Mounted onboard of a small remote-controlled boat or on any kind of small boat, the single beam system offers simplicity, speed and ease of implementation as well as extensive flexibility.
Methodology
- collection of historical data
- single and multibeam bathymetric measurements
- GNSS RTK positioning
- digital terrain model (DTM) and differential calculations
- spatial distribution of sediment deposits
- height/volume curves
- recommendations regarding sediment management
Specific skills
Our Expertise & Development department offers the following specific competences and tools:
- advice, analyses, interpretation of results and recommendations by multi-disciplinary specialists and experts
- multibeam system adapted to the peculiar configurations of alpine lakes
- expertise in acoustic technology for measurements in aquatic environments
- treatment of point clouds and sonar images
- a team that is experienced in these types of readings
- unique system in Switzerland in terms of resolution
Client benefits
The owners of hydroelectric developments benefit from solutions and treatments adapted to their specific needs. It can optimise its production in relation to the actual storage volumes. It can also :
- gain knowledge of the condition of its reservoir and monitor the evolution of aggradation
- optimise and manage purges
- anticipate and plan investments linked to the silting of reservoirs
- understand the sediment dynamic of the lake
- have access to essential data for a global study on sediment transportation in the installation
Other benefits (excluding the hydroelectric sector) :
- precise modelling of watercourses (risk of the water level rising)
- installation of cables, submerged pipelines
- monitoring of sub-lake instabilities and water scouring
- condition of aggradation at ports and in navigable waterways
- quantification of sediment volume evacuated during extraction operations
- quantification of volumes available for extraction (gravel pits or other)
- search for wreckages
- scientific research
