Costly fix urged to keep water flowing in winter
The city’s 104-year-old purification plant on Lemieux Island is having trouble drawing water from the Ottawa River in winter because slushy ice clogs a shallow intake pipe.
It could cost nearly $20 million to extend a pipe deeper into the river and solve the problem, an environmental report says.
The ice jam in the pipes has become headache in recent years that has cost as much as $700,000 annually, in emergency repairs and overtime, to clear. The work is critical to keeping drinking water flowing to homes across Ottawa.
The plant draws, purifies and pumps enough water to serve half the city. The 55-year-old Britannia plant, which also draws from the Ottawa River, treats enough water for the rest of the city. The ice isn’t as much of a concern there, but the city is monitoring it.
In winter, each plant purifies about 200 million litres of water a day. They are permitted to produce more, but cold weather tends to slow production. Neither plant on its own can generate enough drinking water for the entire city in the winter, based on the average daily demand. Tanks and reservoirs have less than a day’s worth of water, so an extended snafu at a water plant would have serious consequences.
There are four intake pipes at the Lemieux Island plant. They extend about 11 metres from the shoreline and are about 1.5 metres below the water surface.
Before 2013, ice problems at Lemieux Island lasted a day or two at a time. It was so bad in 2013 the city had to spend $750,000 on a temporary extension to the pipe to get below the ice. Since water production falls with the extension, it’s not an all-season solution. Instead, the city applies the extension each fall to get ready for the winter.
In the past two winters, the ice started sticking to the temporary pipe extensions. In some cases, divers had to remove the blockages.
The city has spent more than $2 million since February 2013 to clear ice from the intake pipes at Lemieux Island.
The city commissioned an environmental assessment in 2014 to find a permanent solution.
Of the shortlisted options, ranging in cost from $5.9 million to $18.5 million, the city wants the most expensive technique because it provides the best chance to avoid ice buildups in the pipes.
The solution would involve extending pipes 225 metres from the shoreline to the deepest part of the river, across the Ontario-Quebec border. A preliminary estimate puts the cost between $17.2 million and $18.5 million. The city expects to have it done by the end of 2020.
The problem is, the city only has about $7.7 million in the bank for the project and would need to find a way in the budget to pay for the rest.
As a contingency, the city says it will start a $650,000 project that will put an ice boom in the river to capture the ice.
City staff will ask council’s environment committee next Tuesday to endorse the deep pipe solution.