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INUVIK
Inuvik's 50-year-old utilidors require more time, money and personnel than the town has available, meaning repair costs will rise while replacement of the corridors moves at a snail's pace.

Inuvik's 50-year-old utilidors require more time, money and personnel than the town has available. A recent update by engineers let town council know how bad the situation was. - Samantha Stokell/NNSL photo

Two engineers with AECom presented Inuvik's town council with a grim picture of the state of utilidors – the town's answer for sewage and water in a landscape with thaw-sensitive ground - during the Nov. 7 council meeting.

Inuvik has 17 km of utilidors which carry water and sewage to and from buildings. To replace the entire aging infrastructure would cost an estimated $140 to $170 million, 10 times the cost in the south. The town currently has $80 million worth of utilidor to replace, which the town is doing at a rate of 150 metres per year. At that rate, it would take more than 50 years to complete.

"You can't afford to replace, so you have to maintain it," said Michael Maltais, the utilidor engineer with AECom. "Most of it is in fairly good shape, but it needs continual maintenance. It should last until a program allows you to replace it, but there are some weaknesses."

The areas of weakness include the wood piles that support the corridors; frost heaves or settlements that change the direction of flow in the pipes; leaks, breaks, blockages or circulation disruptions in the utilidor; and power or heat outages, which could cause the utilidors to freeze.

Sixty per cent of the utilidors are on wooden piles, which eventually rot and collapse. The lifespan of these supports can be extended by using anti-rot treatment, such as inserting a boron rod into the supports.

Frost heaves or settlements can break the pipes in older systems. Changes in grade also cause problems in the sewage pipes, which require gravity to move the material through the pipes.

With last winter's power outages, the engineers had concerns about power and heat outages. Residual heat from the power plant is used during the winter, but an extended power outage would have a significant impact on the utilidor system.

Continual monitoring of the system could prevent much of the damage from frost heaves, grade changes, rotted pilings and breaks in the system. Having replacement parts on hand would also prevent necessary repairs from being delayed due to shipping from the south.

If the town owned a backup heat exchanger, that would ensure the utilidors wouldn't freeze during an extended power outage. Regular inspection and maintenance of the heat exchange system is also needed.

One more issue is the Supervisory Control and Data Acquisition (SCADA) system, which is a computer that monitors the utilidors. The Inuvik system, which allows for early detection, was installed in the mid-80s and is now obsolete and doesn't work. This puts extra work on the utilidor crew, who must check the system manually.

"I walked the entire utilidor and there's much maintenance needs, some major, some minor," Maltais said. "The quick and short answer is that you're understaffed with three people. You need a full crew to inspect and maintain the system. At least one more, possibly two. A full crew all the time to repair stuff, observe and do inspection."

Right now the town's approach is reactive, rather than pro-active. The lack of staffing means repairs are done once something is broken, not to prevent breaks, leaks or rotting pilings.

Replacing the utilidors happens only during the warm months and is done at a cost of $1.5 million each year. Dowlands won the contract to replace the utilidor. The company purchases the materials and then provides the skilled labour to do the work. Coun. Terry Halifax asked about the possibility of doing the work in-house.

"We're held by the contractors to do the work. Should we look more towards doing it with our staff in the future?" Halifax asked during the council meeting. "Last year we had only one bidder on the job and it was 50 per cent higher than other years."

Councillors debated the pros and cons of purchasing the materials, training staff and doing the replacement themselves, or signing a long-term contract with one company. Money could be saved by purchasing the materials themselves, but that could bring in a whole host of other issues related to liability.

"Now you're the one who is responsible because you bought the materials," Maltais said. "If it failed, is it because of the way they installed it or because the town purchased the materials?"

Another area of concern is the Hidden Lake pumphouse, which provides water to the town in the summer months. During an inspection, signs of the earth shifting were observed, which Maltais describes as is a severe issue with little option for repair. A new pumphouse or water treatment plant is needed. The town has set aside funds for that investment.

The engineers concluded no amount of maintenance can repair a utilidor and eventually all 17 km will need to be replaced.

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