Dams and hydraulic Engineering (Hydro-electric power plant)
- Client: Collectivité Eau du Bassin Rennais (CEBR)
- Assignment: Project management for rehabilitation of the power station:
-
- installation of a new turbine
- works to restore free movement of eels (upstream and downstream migration);
- automatization of spillway valves and adaptation of the control-command and monitoring of the structure
- Assistance to the project manager for the regulatory monitoring of the dam
- Operator: Local Public Company (SPL) Eau du Bassin Rennais
- Completion date: 2014 – 2019
- Total cost of the assignment: 210k €
PROJECT DESCRIPTION AND CHARACTERISTICS
The Rophémel dam is built on the coastal river of Rance, upstream of the famous tidal plant located at the estuary. It is a construction built from 1931 to 1938 of multiple vaults in concrete support system ” Considère”, leaning on granite. The dam consists of 16 thin reinforced concrete vaults of 5,40 m of opening between walls and of 10,80 m to 25,60 m of variable height. Its crest length is 126 m, its height above the natural ground is 26 m (class A) and it creates a reservoir of 4.4 million m³.
This development is dual-use: drinking water production and electricity production.
The hydroelectric plant located at the foot of the dam is currently equipped with two Kaplan turbines that will be replaced by a single turbine:
- Equipment flow rate: 13.5 m³ / s
- Max. : 23.8 m
- Installed turbines: Kaplan type with vertical axis
- Electrical power max. : 2.65 MW
- Estimated annual production: 2.47 GWh
ASSIGNMENT
The Rophémel sur la Rance dam was commissioned in 1934 as part of a hydroelectric concession entrusted to EDF. Since 1963, it has been used for two purposes: water production for the Rennes basin and electricity production during peak periods.
The SMPBR entrusted GEOS Ingénieurs Conseils with project management (design studies and follow-up) relating to:
- installation of a new turbine,
- carrying out work to restore the free movement of eels, both for the upstream and downstream migration,
- automatization of the spillway valves and adaptation of the control-command and monitoring of the structure.
The assistance mission to the project manager for the regulatory monitoring of the dam includes:
- Monitoring and analysis of auscultation data
- Preparation of an annual report on auscultation
- Advanced Technical Visits
- Full Technical Exam
- Security review
