Pointe du Bois Spillway Replacement
The spillway facilities at Pointe du Bois require replacement in order to maintain public and dam safety and to provide a modern and safer working environment for staff.
The Pointe du Bois Spillway Replacement project includes:
- spillway located on the east shore;
- spillway approach and discharge channels;
- earthfill dams;
- transition structures;
- decommissioning of the existing spillway structure.
Key factors considered for the general arrangement of the spillways were:
- maintaining dam safety during construction;
- protecting and maintaining existing lake sturgeon habitat;
- maintaining historic water levels and limit changes to water flow patterns;
- overall cost;
- constructability of the project;
- accommodating the option of building a new powerhouse at a future date.
There are no plans to rebuild the powerhouse at this time. The existing powerhouse will continue to operate with on-going activities to maintain safety and reliability. With these improvements, modern dam safety guidelines will be addressed.
Manitoba Hydro submitted an Environmental Impact Statement to federal and provincial regulators on June 17, 2011. During final design, it was determined that a Revised Arrangement to the spillway and dams would reduce cost, schedule and potential environmental effects. As a result, Manitoba Hydro is seeking regulatory approval for a Revised Arrangement of the principal structures at Pointe du Bois. An alteration to the Original Arrangement was submitted for regulatory approval on August 17, 2012. The revised arrangement includes:
- elimination of the secondary spillway;
- increasing the size of the primary spillway from 5 to 7 bays;
- shifting the primary spillway structure, and associated approach and discharge channels, to the east; and
- main earthfill dam constructed mid-way down the spillway shelf.
- Channel excavation will be completed.
- Installation of the mechanical spillway gates ongoing.