Proceedings 2009/059
Proceedings of the Central and Arctic Regional Science Advisory Process to assess whether upstream passage is needed for Lake Sturgeon at the Pointe du Bois generating station (Winnipeg River); 22 October, 2009
Chairperson: Thomas Pratt
Editor: Holly Cleator
Summary
Manitoba Hydro must modernize the Pointe du Bois Generating Station on the Winnipeg River, which will involve replacing the spillway and associated dam segments. The new spillway may be located slightly downstream of the existing one, but still on the spillway shelf. The powerhouse may also be replaced by building a new one east of and at the same axis as the existing one, or it may be repaired or rehabilitated with no change in footprint. No decision regarding the powerhouse options has been made. The Winnipeg River, between the Pointe du Bois and Slave Falls Generating Stations, contains abundant numbers of Lake Sturgeon (Acipenser fulvescens) which spawn at the base of Pointe du Bois spillway shelf and at the outlet of the existing powerhouse. Lake Sturgeon in the Winnipeg River were assessed as Endangered in 2006 by the Committee on the Status of Endangered Wildlife in Canada. Changes to the Pointe du Bois Generating Station would likely impact the spawning success of Lake Sturgeon below the Station. For that reason, DFO Habitat Management requested advice from Science on whether upstream passage at the Pointe du Bois Generating Station would be beneficial or detrimental to Lake Sturgeon in the Winnipeg River given the potential negative impacts of the proposed new structures on sturgeon spawning habitat below Pointe du Bois, the overall status of sturgeon in the Winnipeg River and the uncertainty surrounding the quality of habitat upstream of Pointe du Bois.
A regional science peer review meeting was held on 22 October 2009 to develop the science advice. Meeting participants included DFO Science, Habitat Management and Species at Risk sectors of the Central and Arctic Region, and specialists from Manitoba Water Stewardship, Ontario Ministry of Natural Resources, Manitoba Hydro, Sagkeeng First Nation, North/South Consultants Inc. and State University of New York – Oswego. Several conclusions were reached. Modernization of the Pointe du Bois Generating Station would change the configuration of the station, thereby altering current flow patterns and habitat availability. These changes could impact spawning habitat suitability. The extent of impact, and its effect on spawning success, would depend on the Generating Station design option chosen. Potential advantages and disadvantages were identified with providing upstream passage for Lake Sturgeon at the Pointe du Bois Generating Station. The key potential benefits would be to increase genetic diversity within the Winnipeg River and to allow Lake Sturgeon, which may be at or near carrying capacity below the GS, to move upstream into areas where unfilled habitat may be available and Lake Sturgeon abundance is lower. The key potential disadvantage would be the loss of Lake Sturgeon from the healthy population downstream of the GS, to the area upstream where the availability of suitable habitat and potential risk of harm is unknown. Several gaps in knowledge need to be filled before a complete assessment can be conducted.
Accessibility Notice
This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.
- Date modified: