Conestogo Dam Rehabilitation Project

Located about 30-minutes northwest of Elmira, the Conestogo Dam was built in 1958 and is one of seven multi-purpose dams built by the GRCA to help reduce the impact of flooding year-round and augment river flows during periods of low flow.

Maintenance projects are regularly completed to ensure the dam is operating safely. Multiple projects have been completed to maintain and upgrade the dam over the years, including earlier phases of this multi-year comprehensive concrete rehabilitation project beginning in 2019. In 2021, an assessment of the upstream face of the dam showed that years of wind, water and ice exposure had resulted in concrete degradation. As a result, the GRCA contracted a company to repair portions of the dam. Work on the downstream walls of the dam was undertaken in 2019, 2020 and 2021, and on the road deck in 2022.

The next phase of this comprehensive project began in the summer of 2024, with the first stage completed in December 2024. This part of the project consists of concrete repairs to the upstream (reservoir facing) side of the dam. The second stage of this portion of the rehabilitation work will begin in June 2025, and is anticipated to be completed by December 2025, subject to change depending on weather conditions or other unforeseen challenges. Future work in 2026 and 2027 will be on the downstream side of the dam and is planned to be scheduled in the fall of each year.

Impact on water levels in the Conestogo Lake reservoir in 2025

To accommodate the concrete work, water in the Conestogo Lake reservoir will be drawn down:

• Water levels will be lower than what would be typical in a normal operating year, similar to 2024. We anticipate water levels will be the same or lower than 2024 to allow adequate time for construction. Conestogo Lake reservoir elevation levels are available on the Conestogo Dam webpage.
• Water levels will be lowered no faster than 20 cm per day in June, July and August 2025. The GRCA has a schedule to keep reservoir elevation at or above the lower rule curve until the Civic Holiday (August 5, 2025).
• Water levels will be lowered no faster than 30 cm per day after Labour Day (September 2, 2025).
• The slope of the shoreline differs throughout the reservoir. Cottagers and boaters should familiarize themselves with the impacts that the drop in height of reservoir water levels of 20 cm and 30 cm/day may have on the amount of shoreline exposed, impacts to docks and boats and other items near the shoreline, and water hazards that may be exposed throughout the season.

Other impacts and service disruptions

• Wellington Road 11 will be reduced to one lane throughout the project, with the exception of long weekends. Please drive with caution and obey all signs and traffic lights.
• Cottagers and recreational users of the reservoir should expect fluctuating water levels beginning in June and through to late fall as the project progresses and adjustments are made to accommodate flood management and flow augmentation. 
• A shorter boating season is expected in 2025. The boat launch and beach at Conestogo Lake Conservation Area may be impacted or out of service earlier in the season than typical. Subject to weather and other factors impacting inflows and reservoir levels, the target is to keep one of the boat launches open until Labour Day weekend. Check the Conservation Area Activity Status page to see the status of the beach and boat launch.As always, the project schedule and operation of the reservoir is subject to change pending weather conditions or other unforeseen challenges.
• There will be no impacts to fisheries within the Conestogo Lake reservoir due to construction or the draw down.