Eel protection devices and operations at 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 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 km 2 Mean annual water flow: 30.8 m 3 /s Run-of-river 3.5 MW hydroelectric dam Located 6.5 km from estuary Maximum turbined flow: 26 m 3 /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 DeviceWaterflow to device m³/s Waterflow to turbines m³/s Efficiency % 42Halog0.5 (7 eels) 4.7 (35 eels) Halog0.5 (7 eels) 9.0 (35 eels) 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 m 3 /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