Possibility of high water levels on Burntwood River
May 11, 2017
Water flow at Manasan Control Structure near maximum operating limits
Manitoba Hydro is issuing a warning to residents and businesses along the Burntwood River near Thompson of the possibility of high water levels and high flows along the river. Water levels behind the Manasan Control Structure, upstream of the city, have reached 649.0 feet above sea level (ASL). This level is near the maximum normal operating limit of the structure before the structure's emergency fuse plug — designed to provide an additional passage for water to flow through the structure — goes into operation. The high water conditions are a result of this spring's snow melt.
The fuse plug is designed to activate under high flows to prevent damage to the rest of the structure. Once the fuse plug is overtopped, it is designed to erode in several hours, lowering water levels behind the structure. However, this could result in an estimated water level increase in Thompson of one to three feet on the Burntwood River over the course of a day.
The Manasan Control Structure, eight kilometres upstream from Thompson, helps provide a stable ice cover on the river to prevent ice jamming and associated problems in the Thompson area, and provide adequate discharge during times of high water flows.
"We are currently monitoring the situation very carefully," said Scott Powell Director of Corporate Communications for Manitoba Hydro. "At this stage we are not anticipating an issue, but we believe it is prudent to notify all residents in the Thompson area of the possibility of this rapid rise in water levels along the river."
Powell said Manitoba Hydro has reduced outflows from the Notigi Control Structure to reduce the amount of water flowing into the Burntwood from the Churchill River Diversion and reduce stress on the Manasan structure. However, any major precipitation poses a risk of further increasing water levels, despite flow reductions at Notigi.
"We are currently placing sandbags on top of the fuse plug simply to provide some additional reinforcement of the structure," said Powell. "Thanks to flow reductions at Notigi, water levels are stabilizing, and we just want to ensure we have no seepage or other issues at Manasan caused by levels being so close to the maximum operations limit."
Manitoba Hydro has advised the RCMP and emergency officials in the City of Thompson of the status of water levels and flows at the Manasan Control Structure as a precautionary measure. The current five-day Thompson weather forecast does not include any significant rain.