2. Fish passage facilities, fish pass efficiency and monitoring techniques
Matthieu CHANSEAU, Michel LARINIER
Association Migrateurs Garonne-Dordogne (MIGADO)
ONEMA-GHAAPPE

3. M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
REGULATIONS
A french law adopted in 1984 requires that any hydro plant must include facilities to guarantee free passage (upstream and downstream) for migratory species
at existing plants in rivers classified as necessary for 'migratory fish'
at new or relicenced plants in all rivers (even those not classified as migratory rivers)
an obligation to ensure upstream and downstream passage
Species considered in the french law
8 diadromous fish : salmon, sea trout, lamprey (2), shads (2), sturgeon, eel
3 « riverine » fish : trout, grayling and pike
European Water Framework Directive : concept of ecological continuity
 the passage of all species has to be taken into account in a more determined way

4. AN OVERVIEW OF DAMS IN THE DORDOGNE BASIN
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
AN OVERVIEW OF DAMS IN THE DORDOGNE BASIN

5. M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
Fish pass facilities

6. Selective for small species
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
DENIL FISH PASS
Selective for small species
Can tolerate only moderate variations in upstream water level
Easier and cheeper than others FP
Discharge generally less than 1 m3/s
Small river

7. A Denill fish pass on a Dordogne tributary

8. Most frequently used type of FP in France and in the Dordogne basin
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
POOL FISH PASS
Most frequently used type of FP in France and in the Dordogne basin
Several types for all species if
Drop from 15 cm to 35 cm
Dissipated power W/m3
Pool hydrodynamic
All rivers
All species

9. Ex. : Bergerac pool fish pass (Dordogne river)
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
Ex. : Bergerac pool fish pass (Dordogne river)
Discharge between 2 and 6 m3/s
Upstream level variation : 2 m
Attraction flow up to 5 m3/s

10. Ex. : Mauzac pool fish pass (Dordogne river)
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
Ex. : Mauzac pool fish pass (Dordogne river)
Discharge : 1 m3/s
Upstream level variation : 1 m
Attraction flow up to 5 m3/s

11. Ex. : Iffezheim pool fish pass (Rhine river)
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
Ex. : Iffezheim pool fish pass (Rhine river)

12. Generally used in 8 m and higher dams Very large numbers of fish
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
FISH LIFTS
Generally used in 8 m and higher dams
Very large numbers of fish
Some problems with small species ; not
adapted to eel
Small overall dimensions
Low sensitivity to upstream water
level variations
But
High operating costs
Low efficiency for small fish because fine
screens (< 3 cm) require for maintenance

13. Ex. : Tuilieres fish lift (Dordogne river)
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
Ex. : Tuilieres fish lift (Dordogne river)
Discharge : 1 m3/s
Attraction flow up to 5 m3/s
Cost : 1.3 M€

14. Ex. : Golfech fish lift (Garonne river)
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
Ex. : Golfech fish lift (Garonne river)

15. No more considered to be an option in France
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
FISH LOCKS
No more considered to be an option in France

16. Large diversity of types : from rough ramps to bypass channels
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
« NATURAL » FISH PASS
Large diversity of types : from rough ramps to bypass channels
All species
Low slope  moderate heigh

17. Carennac rough ramp (Dordogne river)
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
Carennac rough ramp (Dordogne river)

18. First pass built 15 years ago Nylon brushes installed on PVC plates
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
EEL FISH PASS
First pass built 15 years ago
Nylon brushes installed on PVC plates
Recent experiments to test other more robust and less expensive substrates
Very low discharge and important slope (up to 45° and more)

19. Tuilieres eel fish pass (Dordogne river) - 1997
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
Tuilieres eel fish pass (Dordogne river)
- 1997

20. Mauzac eel fish pass (Dordogne river) - 2007
TITLE : Fish passage facilities
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
Mauzac eel fish pass (Dordogne river)

21. Golfech eel fish pass (Garonne river) - 2008
TITLE : Fish passage facilities
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
Golfech eel fish pass (Garonne river)

22. DOWNSTREAM DEVICES

23. About 2 000 hydropower plants in France (40 in Dordogne basin)
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
About hydropower plants in France (40 in Dordogne basin)
One of the most important problem : turbine mortality
Experimental studies in the 90’ for salmon and since 2000 for eel
More complicated problems
Actually, no real satisfactory solution for large dams
Principles
Physical barriers which exclude fish from the turbine intakes
Behavioural barriers which guide, attrack or repell fish
System which ensure downstream passage without damage

24. 50% 100% 20% 10% 2-5% For eel : mortality x 4/5
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
50%
100%
20%
10%
2-5%
For eel : mortality x 4/5

25. Turbine Mortality : empirical formulas
- M% = f(turbine characteristics, fish length)
Probability to pass by the turbines or by the dam
- Ratio turbine flow / river flow
- Configuration of the intake canal and dam
- Migratory fish behaviour
Power house
Turbined flow
Turbine mortality
Dam
Flood gates flow

26. Ex. on the Dordogne basin for salmon smolt
Mean mortality of 20%
One obstacle (Tuilieres) is responsible for 70% of mortality

27. BY-PASS COMBINED TO COVENTIONAL TRASHRACKS
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
BY-PASS COMBINED TO COVENTIONAL TRASHRACKS
Surface by-pass for salmon smolt
Surface and bottom by-pass for eel

28. BEHAVIOURAL BARRIERS Sound and electricity Light for smolt
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
BEHAVIOURAL BARRIERS
Sound and electricity
 Low efficiency (0-15%)
Light
 Improve efficiency
for smolt

29. Surface guide walls for salmon smolts) Only one device in the World
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
BEHAVIOURAL BARRIERS
Surface guide walls for salmon
smolts)
Only one device in the World
(Connecticut river) – 75%
But in 2009, another one in
Tuilieres on Dordogne river !

33. DOWNSTREAM PASSAGE Trapping and transport M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
DOWNSTREAM PASSAGE
Trapping and transport

34. STOPPING POWER STATION AND OPENING GATES High energetic cost
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
STOPPING POWER STATION AND OPENING GATES
High energetic cost
Good knowledge of migration timing
Goog knowledge of fish behaviour
 first experimentation in Tuilieres in 2009 (eel)

35. FISH PASS EFFICIENCY

36. Need of efficiency is variable and depends on
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
FISH PASS EFFICIENCY
Need of efficiency is variable and depends on
the species (ex. : for cyprinids, avoid isolation of the populations)
the location of obstacles
the numbers of obstacles
Efficiency difficult to determine
Percentage of passage (%)
Delays (hours, days)
Number of fish
Number of species
Hydraulic conditions
Efficiency depends on
Location
Discharge / Attractivity
Maintenance
For salmon, the whole population on spawning ground

37. FISH PASS LOCATION 4 entrances M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
FISH PASS LOCATION
4 entrances

38. Ex. Mauzac (Dordogne river)

39.  50% to 70% for salmon

40. DISCHARGE / ATTRACTIVITY Generally between 2 and 10% of concurent flow
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
DISCHARGE / ATTRACTIVITY
Generally between 2 and 10% of concurent flow
Fish pass entrance in a not disturbed area
Ex. Mauzac
(Dordogne river)

41. Dissipated power : 100 W/m3 up to 300 W/m3
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
HYDRAULIC CONDITIONS
Current speed
2.5 m/s for large species
1.5 m/s for small species
Drop : between 0.2 and 0.5 m
Dissipated power : 100 W/m3 up to 300 W/m3
Minimal depth between 0.2 and 0.4 m
For all fish
For large fish

42. One of the main problem on french fish passes
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
MAINTENANCE
One of the main problem on french fish passes
Natural fish passes are less sensitive
Ex. on Dordogne tributaries (summer 2007)

43. For salmon : up to 100% without delay For shad : between 50% and 75%
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
FINALLY
For salmon : up to 100% without delay
For shad : between 50% and 75%
For eel : ???
For lamprey : > 75% ?
For others species : ???

44. DOWNSTREAM DEVICES EFFICIENCY
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
DOWNSTREAM DEVICES EFFICIENCY
Location of by-pass

45. DOWNSTREAM DEVICES EFFICIENCY
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
DOWNSTREAM DEVICES EFFICIENCY
Flow between 2% to 10% of the turbine discharge
Low current velocity (< 0.8 m/s)
Local hydraulic conditions (for ex. no upwelling)

46. BPD : 0.8 m3/s
1.5 m upstream trashrack
BPD : 1.8 m3/s
1.5 m upstream trashrack
upwelling removal by deflector
BPD : 0.6 m3/s
6m upstream trashrack
Bypass efficiency

47. Efficiency for smolts between 55% and 90%
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
FINALLY
Efficiency for smolts between 55% and 90%
Efficiency for eel between 20% and 60%
For others species : ???

48. MONITORING TECHNIQUES Automatic resistivity counter
Trapping
Automatic resistivity counter
Video control
Telemetry
TIRIS tag

49. Fish species recognition Biological characteristics
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
TRAPPING
Fish species recognition
Biological characteristics
But risks of injury (death) or stress
High manpower requirement
No continuous real-time data
(with or without mark/recapture operations)

52. AUTOMATIC RESISTIVITY COUNTER Low cost But no fish recognition
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
AUTOMATIC RESISTIVITY COUNTER
Low cost
But no fish recognition
Only 3 sizes
Tuilieres counter (Dordogne river)

53. Fish species recognition Continuous real-time data
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
VIDEO CONTROL
Fish species recognition
Continuous real-time data
But not all biological characteristics
Problem with turbidity

54. Special counting system

56. Comparison of shad passages at
Tuilieres and Mauzac video stations
Shad passages and water
discharge at Mauzac station

57. Expensive technique (equipment and manpower)
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
TELEMETRY
Expensive technique (equipment and manpower)
But very precise informations about
Fish behaviour
Delays…
The best technique to understand the problems
and to find adapted solutions

59. Atlantic salmon (Mauzac – Dordogne river) Year 2008 0 / 5 upstream
Delay up to 3 months
All fish received at the new fish pass entrance
0 fish received at the old fish pass entrance
Good location of the new entrance
But low attractivity

60. Power plant Trap Pool Inlet canal Discharge Canal canal de fuite 10 m
10 m BR OC EC T DC FC T1 T3 RB Sb FP Bb

61. SEA LAMPREY Golfech (Garonne river) Year 2007
21 sea lamprey just below Golfech
2 pass upstream
19 come into fish lift and 17 go out !

62. Individual informations Passive mark : small reception area
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
TIRIS and PIT TAG
Relatively Low cost
Individual informations
Passive mark : small reception area
SHAD and LAMPREY
(Mauzac – 2005)
75% of fish use the new fish pass entrance

63. M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
IN CONCLUSION
Progress in technology as a result of in situ experiments and assessment of existing structures
A multi-disciplinary approach, calling on both engineers and biologists, is necessary
Residual impact of dams on diadromous species is significant, even with « efficient » fish passage facilities.
The best way to restore longitudinal continuity : remove dams where possible

64. THE BEST SOLUTION FOR FISH
M. CHANSEAU et M. LARINIER
MIGADO / ONEMA
THE BEST SOLUTION FOR FISH
NO DAM !