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Seven Sisters Coffer Dam, Whitemouth, MB

Project data

Location: Whitemouth, MB, Canada

The Seven Sisters Generating Station, located in Lac du Bonnet, Manitoba, is a
hydroelectric generating station that harnesses the power of water to produce
renewable hydroelectricity. Construction of the station commenced in 1929 and
concluded in 1931. However, additional construction occurred between 1948
and 1952 to enhance its capabilities. Presently, the station boasts an electricity
capacity of 165 megawatts, with five transmission lines connected to Winnipeg,
MB; one to Whiteshell, MB; and one to Kenora, ON.


Recently, the Seven Sisters Generating Station faced the need for repairs on its water-facing dam wall, which had experienced delamination and required patching. Since a part of the wall was submerged underwater, the challenge was to develop a solution that would grant access to the affected area while preventing water ingress. Vector Construction turned to PERI for our expertise and assistance.


Vector Construction

Customer's benefit

  • Enclosed work area
  • Prevention of water entry
  • Innovative & efficient solution 

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Mike Berg
Project Manager-Estimator

“From the engineering down to equipment being delivered to site on time, PERI delivered on what they had committed to. The PERI team was great to work with, their professionalism and dedication to the success of the project was very appreciated from the team at Vector Construction.”

PERI solution

PERI provided an innovative and efficient solution for the project. They employed DUO's one- sided wall, anchoring it into the existing structure to ensure stability and support. Additionally, DUO and VARIOKIT were utilized to establish an enclosed work area. The VARIOKIT enclosure not only served as a platform for the construction crew but also provided a structure to attach the DUO formwork, effectively preventing
water from entering the work area.

To manage any water that seeped through, pumps were installed at the bottom of the VARIOKIT enclosure. This ensured that even minimal water ingress was promptly removed. The installation process was facilitated by PERI's engineering installation
sequence drawings and step-bystep guidelines, which offered clear instructions for the construction team to follow.

What sets PERI's solution apart is that competitors had previously shied away from designing systems for such complex underwater repair projects. However, through numerous meetings, conference calls, and guidance from PERI's engineering team and site supervisor, Vector Construction gained the confidence to execute the project successfully.