February 11, 2010

CITY OF WINNIPEG

The Deacon Water Treatment Plant was originally budgeted at $205 million, but additional design features pushed that figure to $300 million.

FOCUS | Water & wastewater

Winnipeg enjoys benefits of recently completed Deacon Water Treatment Plant

PETER KENTER

correspondent

Citizens of Winnipeg are enjoying the benefits of the Deacon Water Treatment Plant, completed in December, to provide the area with top-quality clean water.

Derived from Shoal Lake in Ontario, the water is transported through a 150-kilometre aqueduct to the Deacon Reservoir, just east of the city.

The $300-million dollar project, which broke ground in the summer of 2005, employed between 275 and 400 construction workers at any given time.

The plant, the largest capital project in the city’s history, covers 12,000 square metres and can treat up to 400 million litres of water per day.

“The construction of this project wasn’t driven by any regulation,” says Tom Pearson, project director for the plant. “The idea was conceived by the city prior to the development of the Canadian drinking water guidelines.”

The project began with a $50-million upgrade to the aqueduct, which was built during the Second World War.

“It’s constructed of unreinforced concrete because it was built when steel was at a premium,” says Pearson. “It’s essentially a ditch with a lid on it that was designed to last 25 years. With the upgrades, we can extend the life of the aqueduct another 50 years.”

The construction contract for the water treatment plant was split up to ensure competition and to take advantage of the resources offered by many contractors instead of just one through a period of overheated construction in the Winnipeg market.

“We needed to ensure competition,” says Pearson. “It’s never a good idea to put up a contract so large that only one company can bid on it.

“Also, because we were anticipating a period of active construction in the province, we were able to actually start construction on some parts of the project while we were still designing other parts.”

Builders on the project included Gateway Construction & Engineering Ltd., PCL Constructors Canada Inc., Bird Construction and Comstock Canada Ltd. with the smallest contract bid at around $10 million.

The initial budget for the plant was $205 million with a number of factors contributing to the increase in cost.

“Part of it was attributable to design creep,” says Pearson.

“We didn’t originally design the plant to have standby power generation or an on-site chlorine facility. Some of the cost was the result of the overheated construction market and some of the prices of construction materials went up significantly. The unit cost for pilings doubled in a space of months and the price of concrete also increased.”

The project was initially scheduled for completion a year earlier but local concrete contractors were so overworked, they simply couldn’t bid on the project.

“The market was very tight, so when we put the $56-million bulk concrete contract out for tender, the bidders told us that unless we adjusted the project schedule they couldn’t bid at all,” says Pearson.

One of the biggest construction challenges involved soil stability issues while excavating for deeper piping.

“But I think the people with the toughest job were PCL on the concrete work,” Pearson says.

“There were a lot of massive pours and slabs early on in construction and then a lot of complicated formwork around the smaller tanks.” In all, 35,000 cubic metres of concrete were poured.

Once complete, the plant went through an extensive testing regimen before it could supply water to the city.

“Just after we started the tests, the temperature of the water dropped considerably and we had a challenge dialing in the water treatment dose rates and optimizing the process,” says Pearson.

“Our water quality is quite good to begin with in terms of turbidity, but cold water is much tougher to treat than warmer water.”

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