Fish injury and mortality in spillage and turbine passage
- RMC Environmental Services, Drumore, PA (United States)
Spillage rather than turbine passage has generally been considered the more benign route for fish passing hydroelectric stations. However, recent studies utilizing the HI-Z Turb`N Tag recapture technique indicate that fish survival may be similar for these passage routes. Short-term ({<=}1 h) survival rates determined during 25 passage tests at propeller turbines on a variety of fish species were compared with those from six sluice/spill tests. Turbine passage survival data were partitioned by fish size, individual turbine unit size, and efficient or inefficient mode of turbine operation. The survival rate in all the turbine passage tests ranged from 81 to 100% (median 96%). Survival estimates were generally similar over the entire range of turbine discharges tested and regardless of operational mode for fish {<=}200 mm (93 to 100%; median 96%). However, studies on fish >200 mm where smaller turbines operated inefficiently were more variable. Estimated survival rates of 81 to 86% were obtained for these larger fish. These latter studies occurred at horizontal propeller type turbines where an inefficient wicket gate or turbine blade setting was tested. Survival rates obtained during the sluice/spill tests ranged from 93 to 100%, with a median of 98%. Although fish species or size did not appear an important factor, the physical characteristics of the sluice/spill area apparently did affect survival. Unobstructed spills yielded higher survival rates. Since similar passage survival rates were obtained for turbine passage (96%) compared to spill passage (98%), the strategy of diverting fishes over spillways or through bypasses should be reexamined. This is especially true when bypasses or spills are suggested as mitigation to protect emigrating juvenile anadromous fishes. Whichever strategy is chosen a quantitative evaluation of each route should be undertaken.
- OSTI ID:
- 220072
- Report Number(s):
- CONF-9507190-; TRN: 96:000708-0154
- Resource Relation:
- Conference: Waterpower 1995: international conference, San Francisco, CA (United States), 25-28 Jul 1995; Other Information: PBD: 1995; Related Information: Is Part Of Waterpower`95. Volume 1-3; Cassidy, J.L. [ed.]; PB: 2869 p.
- Country of Publication:
- United States
- Language:
- English
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