Environnemental Engineering (Fish pass structures)
- Client: VOEnergies Production SA
- Assignment: Complete Project Management
- Total cost of work: 400 kCHF
- Total cost of the assignment: 48 kCHF
- Completion date: 2009-2013
PROJECT DESCRIPTION AND CHARACTERISTICS
As part of the construction of the Moulinets dam, GEOS studied a concept of crossing the fall of nearly 7m to ensure the free migration of fish.
Given the difficulties encountered in installing a conventional poolway, the installation of a fish lift has proved to be a proven solution in narrow situations where there is a clear lack of space.
The principle of such a structure is relatively simple: by placing the lift in the same place where the fish accumulate at the foot of the dam, the fish are attracted by an attraction flow of 350 l / s, supplied by a DN350 stainless steel pipe from the reservoir to the lift. For the attracting current produced to be sufficient (with a speed of 1.5 m / s), an opening of reduced size is placed at the lift entrance.
The fish are therefore attracted to a net that carries them about 7m higher. From there, they are brought to harbor with the aid of water pumped in a pipe over the crest of the dam.
The climbing and descent movements are automated and according to a periodicity depending on the time of year and the species to be transported.
With regard to downstream migration, a system of removable flaps has been implemented in the control grid of the plant. When the grid flaps are raised, fish can pass through the grid. They are then recovered in a chute, followed by a trapping tank and a downstream discharge pipe.
ASSIGNMENT
These studies consist in particular of performing the following services (according to SIA 103 (Swiss Standard)):
- Phase 31: Pre- Project;
- Phase 32: Design of works;
- Phase 33: Application Procedure;
- Phase 41: Invitations to tender, comparisons of bids, proposals for tenders;
- Phase 51: Implementation Project;
- Phase 52: Execution of works;
- Phase 53: Commissioning, completion
