eel protection devices and operations at the rimouski river hydroelectric powerplant: a win/win...
TRANSCRIPT
Eel protection devices and operationsat the Rimouski River Hydroelectric Powerplant:
a Win/Win approach that works
Guy Verreault and Jean Therrien
Ministère des Ressources naturelles, de la faune et des parcs du Québec
Genivar Consultants
Introduction
• Research / licensing process• Dam and hydropower plant rebuilt in 1996-1997• Eel migration surveys (upstream and
downstream) since 1994• Salmon and eel upstream and downstream
facilities• Downstream device tested: bypass with light in
1997, and with screen in 1998• Main task: eliminate turbine mortality without
significant loss of electricity production
Study area: Rimouski River
River drainage: 1637 km2
Mean annual water flow: 30.8 m3/s
Run-of-river 3.5 MW hydroelectric dam
Located 6.5 km from estuary
Maximum turbined flow: 26 m3/s
Water intake velocity: 0.7 m/s
STUDY AREA - DAM VICINITY
Downstream device
• In 1997, three components: a light barrier, a bypass, and a fine grid (1 cm) inclined screen (effectiveness evaluation)– Light device (90 W submersible mercury
bulbs, 40 Lux at 2 m with 30˚angle) in the water intake
– Bypass in the wall of spillway gate– Fine grid (1 cm) inclined screen behind
lighting barrier• In 1998, two components: a bypass and a
fine grid inclined screen.
BYPASS PLAN VIEW
The results
Ligth avoidance device
Sample Device Waterflow to device
m³/s
Waterflow
to turbines
m³/s
Efficiency
%
42 Halog 0.5
(7 eels)
4.7
(35 eels)
7.7
42 Halog 0.5
(7 eels)
9.0
(35 eels)
12.5
26 Halog
+ Hg
0.5
(0 eel)
8.8
(26 eels)
0
• Efficiency of the light system in 1997: 0 to 12.5%
• Unsufficient lighting on edges
• Backup screen diverted all migrants
Light avoidance behavior
• Current velocity was not too fast (Taft, 1998)
• Water flow in the bypass was correct (0.5 m3/s)• Problem lies in:
– Dark coloring of the water– Low intensity of lighting
• Behavioral barrier are not 100% effective with eel… (Hadderingh et al., 1992) and many other animals
• Field experiments may differ with laboratory observations
Experimental design: alternative diversion
Efficiency: 100%
• Physical barrier tested the following year
• Total efficiency when adequately installed
• Minor adjustments required for total diversion
• Great concern with leaf clogging
• Physical barrier is effective in any water condition
Clogging with leaves and debris was of great concern
Air compressors
Conclusion• High survival rates could be achieved
with simple device at small hydrodams
• Technical problems could be solved with imagination
• No significant loss in electricity production when protection devices are installed and well operated
• Moreover, strong involvement from dam operators is the main factor for a successful protection of downstream migrants