R Thomas Orr Dam

The R Thomas Orr Dam is a recreational structure located on the Avon River in the City of Stratford, east of the Huron Street bridge. The dam was built in 1964 at a cost of $260,000, and replaced an existing structure. The dam creates a reservoir, called Lake Victoria, that is a focal point for the Festival City. The lake is approximately 1.6 kilometres long with an average width of 112 metres, and covers 16 hectares. The upstream drainage area is 89 square kilometres of mainly agricultural land.

Lake Victoria Drawdown – Updates

Lake Victoria has returned to normal summer operating levels after the heavy rainfall on August 28. Water levels had been gradually increasing following the debris removal and closure of the sluice gate at the R. Thomas Orr Dam at the end of July. As the lake was refilling, water was also being released to support aquatic life downstream in the Avon River.

The Rotary Club of Stratford was preparing to pump water into the Avon River from a nearby quarry (with the necessary permit from the Ministry of the Environment, Conservation and Parks) but had not started pumping the water yet.

RT Orr Dam is a recreational structure that provides various recreational opportunities in and around the lake that it creates, which is a focal point in Stratford鈥檚 park system. While not a flood control dam, the dam gates must be able to be operated to avoid upstream flooding. Moving forward, the UTRCA and the City are considering options for debris management to reduce the likelihood of a recurrence.

Aquatic Species:聽An aquatic species recovery effort was undertaken by UTRCA staff during the drawdown of Lake Victoria. Led by our Aquatic Biologist, a team of 12 staff spent three days along the shoreline rescuing stranded mussels, and one puddle of fish (Common Shiner, Bluegill, and Green Sunfish) which were netted back into the water. While some Snapping Turtles were spotted by the reservoir, they had successfully moved to safer areas during the drawdown. Other reports of turtle sightings did not require response.

Due to the extreme heat in the days leading up to the drawdown, water temperatures were found in the 30 to 37 degree range. Water temperatures this hot cause stress for fish, mussels, and other species. The gradual drawdown avoided exacerbating this problem and provided time for staff to respond.

The recovery efforts were successful in moving 1,075 stranded mussels from low water areas to further upstream where water levels remain higher. The types of mussels found include Fatmucket, Slippershell, Creeper, Creek Heelsplitter, Cylindrical Papershell, and Giant Floater.

Freshwater mussels offer several benefits to aquatic ecosystems, including water filtration, nutrient cycling, and support for the food web. They act as natural water filters, improving clarity and removing excess nutrients. Their role in the ecosystem also extends to carbon sequestration and providing a food source for various animals. Freshwater mussels are the most imperiled aquatic species in Ontario and are an important population in the lake鈥檚 ecosystem.

Lake Victoria Filling Progress/Forecast:聽Filling Lake Victoria without significant precipitation will be a slow process and it is difficult to forecast how quickly it can be filled.

The lake has risen 0.6m since the debris was removed from under one of the sluice gates on July 31. The rise will slow as the lake surface area gets bigger (i.e., as the water spreads out over a wider area). Inflows from the Avon River are likely declining as well, making it even more challenging. Flows at most stream gauges across the watershed have been declining, due to the prolonged dry spell.

While there is some rain in the forecasts, the amounts are not likely enough to generate the runoff needed to help fill the lake. We continue to do what we can to bring the lake back up while still maintaining flows downstream.

Debris Removal:聽Part of the efforts by UTRCA staff to get the north sluice gate closed involved removal of debris from in front of the gate. The water levels were low enough that staff could safely access the dam by boat to cut and pry loose the underwater debris, removing branches and debris that were wedged in place, as well as extensive smaller woody material.

When opening the gate, some debris would have passed downstream but not much was visible floating. Since this material was waterlogged, it would tend to stay hidden underwater.

As the reservoir rises, stoplogs can be used to better control flows through the gate. Staff also removed dense mats of small branches from in front of the south gate to allow for stoplogs to be installed.

Debris Cleared and Sluice Gate Closed at RT Orr Dam: 糖心直播 (UTRCA) staff have now safely cleared the debris that had prevented the sluice gate at Stratford鈥檚 RT Orr Dam from closing. With that sluice gate now closed, Lake Victoria will begin to refill. How quickly the reservoir fills, and normal recreational activities can resume, will depend on rainfall.

The UTRCA is closely monitoring flows in the Avon River below the dam. Water levels may be lowered in the channel between the dam and John Street to maintain flows downstream. It is also possible that Lake Victoria may go down slightly as discharge from the dam is fine-tuned but it is not expected to fall significantly.

UTRCA staff continue to move aquatic wildlife that had been stranded as Lake Victoria drained over the past few days, but the gradual change in water levels gave many species enough time to move on their own. Please continue to watch out for turtles that may be moving along or across road, and report any turtle sightings on the聽Turtle Reporting Form. Your report will go directly to the Southern Ontario At Risk Reptiles (SOARR) team who will respond ASAP. If you are unable to complete this form, please call Scott Gillingwater, Species at Risk Biologist: 519-451-2800 ext. 236.

Water levels in Lake Victoria continue to lower at a rate of 25mm/hr. Debris under the sluice gate still prevents the gate from fully closing.

As the water level recedes, the river channel will become narrow, exposing most of the lake bed. The UTRCA鈥檚 Aquatic Biologist has been on site monitoring the water level, quality, and the impact on aquatic species. The gradual draw down has provided time for species to move to larger pools of water; however, as water levels continue to drop and water temperatures increase, some aquatic wildlife may get stranded. The UTRCA will respond to these instances as appropriate and feasible. No aquatic species at risk have been found in the area.

The draw down will continue until the water level reaches a point where staff can safely access the gate and remove the debris. The gate will then be closed again so that the reservoir can begin to refill, while maintaining downstream flows. How quickly it refills will depend on how much rain we get.

During the storm on Thursday, July 24, a sluice gate at the RT Orr Dam in Stratford was operated automatically to release water from the lake and avoid flooding upstream buildings and roads. While the gate was only open a short time, it was long enough to draw debris under the gate so that it could not be closed completely.

Efforts by the 糖心直播 (UTRCA) to flush out the debris have been unsuccessful. As a result, Lake Victoria has been draining. It is likely that the lake will be fully lowered before the debris is able to be removed and the gate closed.

Lake Victoria will begin to refill once the gate is closed again, but how quickly it fills will depend on rainfall. It is important to maintain flow in the Avon River downstream of the dam during this process, to support aquatic health.

The UTRCA understands having the lake down even briefly in the summer causes significant problems. There are a number of businesses, events, and activities that will be affected by this unavoidable drawdown of Lake Victoria.

The UTRCA and the City of Stratford appreciate your patience and understanding as this issue is addressed and will provide updates as available.

Frequently Asked Questions

  • The UTRCA is responsible for the operation and maintenance of the dam. The City of Stratford pays the UTRCA a levy which covers the cost of dam operations, maintenance, and capital projects. The UTRCA contracts some of the monitoring and operations to the City.

  • Seasonally:
    • Winter levels are maintained by stop logs, which are typically installed in front of the south gate, which is raised to allow flows to pass.
    • In April, the gate is lowered incrementally to slowly increase water levels in the lake to the summer level, while maintaining flow downstream.
    • In November, the gate behind the stop logs is opened incrementally, to slowly draw the water level in the lake down to the winter level.
  • During Rain or Runoff Events:
    • Summer water level is maintained by the concrete weir which juts out upstream of the middle of the dam.
    • Gate operations are automated to enable quick response to stormwater runoff.
    • As water levels in the lake rise, the gates are opened to release more water, preventing the lake from flooding properties and roads upstream. As the water levels go back down, the gates automatically close.
  • When a Gate is Removed:
    • The south gate was refurbished over the past winter and put back in place earlier this year. The north gate is also scheduled for refurbishment and maintenance.
    • To allow filling of the lake in spring 2025 while the south gate was still being refurbished, stop logs were installed in its place to bring the water up to the summer level.

  • Woody debris is naturally transported through rivers. Although the parkland surrounding Lake Victoria is well-manicured, there are many trees overhanging the water. In addition, the Avon River upstream of the lake is a natural river with streambank vegetation that can be carried downstream, particularly in the spring.
  • Trash also accumulates in the lake. Items removed from around the dam included various metal objects (e.g., shopping cart, bike tires, bike frame, drone, etc.).

  • Debris is cleared regularly when it affects dam operations. Typically, it is more of a concern in the spring.
  • Debris tends to settle in the deep water in front of the gates, where it cannot easily be removed without fully draining the reservoir due to water depth, clarity, and safety considerations.
  • Previously, when debris has become lodged under a gate it has been resolved by opening the gate to flush the debris out. This is easier in the spring, when debris is more common and the higher inflows into the lake allow the lake to return to summer operating levels faster.

  • The gate opened automatically during the July 24 rainstorm to release water and prevent the lake from flooding properties and roads upstream. During the short time the gate was opened, debris became stuck under it and prevented it from closing again.
  • When UTRCA staff manually operated the gate in an attempt to flush the debris through, the debris did not dislodge. With each attempt, the debris kept the gate further open. Therefore, there was reason to believe that raising the gate even further would make the problem significantly worse and the water level would drop much faster.
  • If the gate were raised too much and could not be quickly closed again, the resulting rapid drawdown of Lake Victoria would threaten aquatic life in the lake.

  • The gate refurbishment is not related to the debris that prevented the gate from closing. Both gates are operating normally.

  • Dredging a lake is a complex undertaking with significant environmental considerations and regulatory approvals. This idea has been raised in the past and may be investigated further in the future.

  • Options for improved debris management in the lake and at the dam will be discussed with the City of Stratford.
  • A major upcoming capital item is a safety boom, which can be designed to also help manage floating debris and keep it back from the dam. The boom is currently being designed. Another capital project is the gate refurbishment, which has been completed on one gate and is planned for the second gate next year.

  • The gradual drawdown provided time for many fish, turtles, and other aquatic life to move as the water receded. UTRCA staff were able to move many more as the lake got lower.

  • UTRCA undertook an aquatic species recovery during the drawdown of Lake Victoria. Led by the UTRCA鈥檚 Aquatic Biologist, a team of 12 staff spent three days along the shoreline and mud flats rescuing stranded mussels as well as moving some fish (Common Shiner, Bluegill, and Green Sunfish) trapped in a puddle.
  • The recovery efforts moved 1,075 stranded mussels from low water areas to further upstream where water levels remain higher. The mussel species included Fatmucket, Slippershell, Creeper, Creek Heelsplitter, Cylindrical Papershell, and Giant Floater.
  • Freshwater mussels offer several benefits to aquatic ecosystems, including water filtration, nutrient cycling, and support for the food web. They act as natural water filters, improving clarity and removing excess nutrients. Their role in the ecosystem also extends to carbon sequestration and providing a food source for various animals. Freshwater mussels are the most imperiled aquatic species in Ontario and are an important population in the lake鈥檚 ecosystem.
  • While some Snapping Turtles were spotted by the reservoir, they had successfully moved to safer areas during the drawdown. Other reports of turtle sightings did not require action.

  • Refilling Lake Victoria will take time and is very dependent on upstream runoff from rain events. The UTRCA will continue to operate the dam to capture runoff but some water must be released through the dam to maintain sufficient flows downstream in the Avon River to support aquatic life.

  • The UTRCA has received various inquiries about opportunities to pump water from upstream sources into the Avon River to help fill Lake Victoria. Staff have calculated that filling the lake by mid-September would be a significant undertaking due to the rate and volume of water that would be required.
  • The Ministry of the Environment, Conservation and Parks is responsible for approvals if pumping is pursued. It is our understanding that a proposal to pump and discharge into the Avon River would be assessed based on water quality, quantity, and duration of pumping. This assessment will need to consider the impact on aquatic life downstream.
  • Should a qualified consultant be hired, UTRCA would provide technical information needed to help determine if an approval application could be initiated with the Ministry.

  • The UTRCA is continuing to review the circumstances and the variables that impacted the operations, including the gates. Staff will be discussing the event with City of Stratford staff and identifying areas for improvement.