1. Sedimentation control behind a multipurpose tidal hydropower dam on the Rance river estuary
The World Association for
Waterborne Transport Infrastructure
Presentation by Mr Geoffroy CAUDE
Permanent member of the French High Council for Environment and Sustainable Development 1

2. Summary of the presentation
1- The river Rance tidal hydropower dam and the way it has been operated
2- Analysis of the sedimentation process
3- Recommendations produced by the mission to the stakeholders

7. The hydraulic optimization of the tidal dam

8. The increasing sedimentation process in the estuary

9. The Rance estuary ‘s sedimentation between 1889, 1956 and 1982

10. The type of deposited sediments along the Rance estuary ( from C
The type of deposited sediments along the Rance estuary ( from C. Bonnot-Courtois-1982)

11. The existing water levels behind the dam before 1966 and after

12. The CEREMA study’s main conclusions
impossibility to produce a global sediment balance in the estuary since the building of the dam
impossibility to simulate through a numerical model the effects of the dam upon the sedimentation process
the essentially marine origine nature of the deposited sediments themselves
- the sedimentation creates obstacles to the development of some navigation activities

13. The ongoing sedimentation management process in the Rance estuary
1- Flushing at Le Chatelier dam
2- Dredging operations
3- Other hydraulic operations
4- Other possible techniques

14. Flushing operations between 1996 and 2015

15. Recommendations produced by the mission to the stakeholders
A full sedimentation management programm with three combined components :
a short term mud pit operation called Lyvet 3
a 5 years experimental program of sediment management including alternative techniques
- a R and D associated program to improve numerical modelling with stable bathymetry measures in order to progress in the scientifical understanding of the sedimentation process, which would require a scientific committee with international experts

16. Territory project under discussion

17. See you at our next PIANC World Congress
34rd PIANC WORLD CONGRESS
Panama in May 2018
See you at our next PIANC-SMART Rivers Conference
PIANC-SMART Rivers Conference
Lyon, France in September 2019
See you at the next PIANC-COPEDEC Conference
PIANC-COPEDEC X Tehran, Iran in 2020

18. Thank you for attention Merci de votre attention