Lafleche Dam Low Level Outlet Conduit Remediation
The Lafleche Dam in southwestern Saskatchewan was originally constructed in 1958. The dam’s reservoir (Thomson Lake) is used for municipal water supply, irrigation and recreation. The dam offers flood protection, and its low level outlet conduit is needed for reservoir management and riparian flow passage.
In 2018, an inspection of the conduit revealed severe deterioration of the pipe which presented a significant dam safety risk due to internal erosion. KGS Group developed a solution using an array of innovative conduit replacement and rehabilitation methods, including trenchless technologies such as slip-lining and Cured in Place Pipe (CIPP) replacement. The work required excavations and other construction activities at the toe of the in-service dam which necessitated a comprehensive dam safety surveillance program. KGS implemented a state-of-the-art instrumentation plan with telemetry to monitor the performance of the dam during critical high risk construction stages.
The project was completed on schedule and within budget just before winter onset, under a relatively short construction season. The low level outlet was returned to full service in September 2022 following final commissioning of the new slide gate equipped with a cathodic protection system.
Project Highlights
- Inspection and assessment, detailed design, construction supervision, dam safety surveillance and real‑time instrumentation with telemetry
- Renewal of low‑level outlet conduit at an in‑service dam and work at the dam toe through a short construction season
- Trenchless methods (slip‑lining, Cured‑in‑Place Pipe), new slide gate, cathodic protection system and state‑of‑the‑art monitoring through critical stages
Caribou Falls Block Dam 2 Reconstruction
Block Dam 2 is one of four embankment dams that contain the Caribou Falls Generating Station reservoir in northwestern Ontario. After 60 years of operation, the dam sustained unexpected slope movements. With KGS Group retained to carryout detailed design and construction supervision, Ontario Power Generation awarded the construction contract to Peter Kiewit Sons Ltd. Together, OPG, KGS and Kiewit reconstructed the dam through most of 2019 and finalized the work in late 2020.
The team applied advanced investigation and laboratory testing techniques, innovative materials, sound engineering judgement and progressive construction methodologies to design and build a new zoned rockfill dam with a cement-bentonite wall (CB wall) core. The design integrated constructability, risk mitigation and schedule saving strategies at the planning level.
Despite unforeseen challenges, all parties persevered using a “One Team” approach. As a result, the project was successfully completed, restoring the dam to modern standards and the station’s generating capacity while preserving the natural surroundings in this wild and beautiful project setting.
Project Highlights
- Detailed design, materials and lab testing, constructability planning, risk management assessments and construction supervision
- Full reconstruction of a 60-year-old structure
- New rockfill dam with cement‑bentonite cutoff wall core
- Progressive construction methodologies and schedule‑saving strategies embedded at planning
- Restored generating capacity and dam service, compliance with modern standards and improved stability and performance