Watering lawns will no longer be p pipe dream
More water will be piped to the filtration plant in Vaudreuil to meet growing demand of residents
Thankfully, Sandy was merciful.
The aftermath of the tropical storm brought some heavy winds and a little rain to the region, but not with the intensity that was forecast.
While that was good news for the public, it was even better news for Marc Côté, chief of technical services for the city of Vaudreuil, who was worried about losing a 660-metre long pipe, 40 inches in diameter, that was floating in the Vaudreuil Bay of Lake of Two Mountains, behind the city’s beach volleyball courts.
Made of high-density polyethylene, the pipe will be the new intake for the ever-growing city, so that it can meet demand of residents who have already endured lawn watering bans for three consecutive summers.
The city is adding a wider pipe to the bay, which will bring more water to the filtration plant. Begun this year, the $12-million project has met a few challenges along the way. It was delayed for several weeks because the traditional method of directional drilling underneath the riverbed wasn’t possible, because work crews ran into huge rocks they couldn’t drill through. The city had to ask the provincial environment ministry for permission to dig a trench where the pipe will sit, and then bury it. That method causes more damage to the marine life in the lake, so the city had to take some additional precautions, like surrounding the work site with a large curtain, which will limit the effects. The curtain will be removed once the project is completed and all the sediment has resettled on the river bed.
But time isn’t on Côté’s side. The city faces a government-imposed Dec. 20 deadline to complete the project before work must halt for the winter.
If that wasn’t enough, crews lost two days of work because of the threat from the hurricane. They spent most of Friday and Monday shoring up the pipe, by dumping huge concrete blocks into the water and attaching them to the pipe with chains. They were worried high winds could take the pipe away, or break it. The wind didn’t affect the pipe at all, the city confirmed Tuesday, but crews will have to undo the chains and bring up the blocks after the storm passes through.
“This is what happens when you work with nature,” Côté said Monday afternoon as he surveyed the site.
Côté is hoping there aren’t any other unforeseen events until the end of the year.
Getting the pipe in place has been a challenge. It arrived in 15-metrelong segments and had to be soldered together on the water.
After the pipe is buried, a vertical piece will protrude into the river. It will be covered with a protective cage made of wood, which will prevent large pieces of debris from getting into the pipe.
Last year, the city drilled underground and added the pipe leading from the city’s filtration plant to the water. The two pipes will sit next to each other underground, and a basin will be built around them so that water from the water-bound pipe goes into the section connected to the filtration plant.
“We don’t connect the pipes, because that way if there is something wrong, and we have to go in, we have access,” Côté explained.
When the project is completed, the new pipe will add 24,000 cubic metres of capacity per day to the city’s filtration plant. The current pipe has a maximum capacity of 16,000 cubic metres per day.
But even after the pipe is connected, there won’t be instant relief for thirsty lawns.
The city’s filtration plant has built a temporary basin for the new pipe to increase capacity by 5,000 cubic metres per day, just for next year.
For the summer of 2014, the city plans to add pumps, and new filtration equipment, and build a much larger basin to meet the capacity of the new pipe. That project is estimated to cost $17 million, and would necessitate enlarging the building, said Christian Gendron, director of water services for the city.
Gendron said the goal is to respond to the maximum demand by city residents. The average demand is 11,000 cubic metres per day, but in the summer, when people are watering their lawns, it has ballooned to 30,000 cubic metres in one day.
But capacity is also dependent on the level of water in the lake. “Last summer, the level dropped dramatically by 15 centimetres in just a few days,” he said.
He explained that when the lake levels are low, the pressure in the intake pipes is also low, so the city can’t produce as much clean water for residents.
Capacity dipped to 11,000 cubic metres per day last summer, when the city decided to put in place a ban on watering lawns.
“The ultimate goal is for there not to be watering bans,” Gendron said. “Of course, there will always be restrictions so that we don’t waste it.”