Ottawa

Ottawa faces $18.5M fix to unclog frozen pipes, councillors told

Tiny, needle-like ice crystals known as "frazil ice" are causing big problems at one of Ottawa's two water purification plants, and could cost taxpayers millions of dollars to combat, city councillors heard Tuesday.

Environment committee OKs extending Lemieux Island intake pipes to escape troublesome 'frazil ice'

Temporary extensions to the drinking water intake pipes are installed at Ottawa's Lemieux Island water purification plant. (City of Ottawa)

Tiny, needle-like ice crystals known as "frazil ice" are causing big problems at one of Ottawa's two water purification plants, and could cost taxpayers millions of dollars to combat, city councillors heard Tuesday.

Frazil (pronounced "frazzle") ice has become such a challenge at the Lemieux Island plant that divers had to go into the Ottawa River last winter in an attempt to thaw frozen drinking water intake pipes.
Frazil ice forms in the rapids above Lemieux Island. (City of Ottawa)

In a presentation to Ottawa's environment committee, staff described frazil ice as small, needle-like crystals that form on cold, clear nights in the rapids upriver from Lemieux Island.

As frazil ice forms, it sticks to metal objects. When it builds up as a mass of slush under the river's winter cover of ice, it's drawn into the plant's intake wells, clogging pipes.

Ice forces shutdowns

"It's not new. It's been around for some time," plant manager Paul Montgomery told councillors. "Is it getting worse? The answer to that is they seem to be more lasting, and they seem to be more frequent."
A City of Ottawa employee shovels ice from an intake screen at the Lemieux Island water purification plant. (City of Ottawa)

Since January 2013, the city has spent hundreds of thousand of dollars each winter to keep the Lemieux Island plant free of frazil ice. While the Britannia plant upstream has been largely spared because it's surrounded by deeper water, frazil ice "modestly impaired operations" there for a few weeks in 2015, according to the staff report.

Ice buildup has also forced temporary shutdowns at the Lemieux Island plant, cutting its normal daily production of 200 megalitres of drinking water by more than half.

During recent winters, the city has attached temporary extensions to the intake pipes, sending them further and deeper into the river where frazil ice isn't such a problem.

Permanent solution pegged at up to $18.5M

A permanent solution — installing pipes that will stretch to the Quebec side of the river, 225 metres from the Ottawa shoreline — is estimated to cost between $17.2 million and $18.5 million.  

The pipes will draw water from a depth of 17 metres.
City staff presented various options to deal with frazil ice at the Lemieux Island water purification plant. The permanent pipe extension preferred by the environment committee is shown in pink. (City of Ottawa)

Staff have identified $8 million in a capital account for the project, but the remainder of the cost would have to be borne in the city's budget. The city may also seek federal infrastructure funding for the project, should it be approved.

Councillors on the environment committee heard about four other possible solutions, including a berm and a boom to divert frazil ice, but in the end backed staff's top choice to extend the intake pipes.

The committee's decision still needs the approval of city council.