Whoa water!
Project too close to water table; ditches collapse
Bob Vrbanac, Waterloo Chronicle (Jul 5, 2006)

Fears of building on the Waterloo moraine came true last week when construction crews had to pump thousands of gallons of fresh water out of the Wideman Road extension and flush it out into local storm water management ponds.
Kevin Thomason, president of the Sunfish Lake neighbourhood association and a big backer of the Environmentally Sensitive Lands designation for the Laurel Creek head waters, said he was shocked to see all the water being siphoned off, especially when he and others had warned the city of potential problems with a road that goes nowhere.
Thomason said he was at the council meeting in May when council approved the Wideman Road extension to service the new subdivision.
But he was concerned that after the first 200 metres of the project, the roadway was only going to service a potential development on the much-contested Owens property.
It's in an area where the water table is particularly close to the surface and ripe for these types of problems, he said.
Those fears came true last week when construction crews from PEIL Contracting completed the first 200 metres of the road extension and were starting work on the remainder.
They found they were entering the more sandy parts of the moraine, which help convert rainwater into potable water that ends up in the aquifer below.
The excavation ditches started to collapse and became swamped by the sheer volume of water rushing in.
It was at that point that the contractor and city sought Ministry of the Environment and Waterloo Region approval to dewater the area and put in a sanitary sewer pipe more than four to five metres down.
They got approval to remove up to 360,000 litres a day over a two-week period that ended last Friday.
Thomason said that dewatering lowered the local water table in outlying wetlands and wells surrounding the site. It also raised the level of water that would be lost to evaporation in local stormwater ponds.
He took many pictures to provide evidence of the dewatering.
It was a waste of water he never expected on that scale, especially with the region imposing strict water restrictions for this summer. And it left him wondering when this valuable resource would be returned to the local water table dependent on rain water for replenishment.
He sent his concerns to the city and has yet to see a response from anyone on council.
Thomason said he doesn't feel city staff adequately explained the potential for dewatering when the original motion was presented, which was supported by all of council except for Coun. Jan d'Ailly.
"That's been one of the most disturbing things here is the complete lack of communication," he said. "There wasn't enough communication from staff to council and the public about the scope of this, and what this project entailed to begin with.
"The people who live on Wideman Road are still waiting for any communication from the city."
Thomason said he never thought they would dig a sewer line almost three storeys deep into the moraine area. He was stunned by the outcome.
"We no more envisioned that they would try to do that than if they tried to hang the sewer from the trees," he said. "Even if these are normal construction practices, this is not a normal area.
"This is the one and only source for our drinking water and we've got to treat it better."
Thomason said in addition to the environmental costs, he wondered about the cost overruns of all that pumping.
Thomas Daniel, the project manager for the Wideman Road extension for the city, said the potential for dewatering was always part of the proposal. The costs are in keeping with the original $1.4-million project that was tendered, he said.
"It is a common practice to do dewatering," said Daniel. "There is a high water table there, and we had included those items in the contract and the contractor quoted for that item.
"We don't have to pay any extra money for the dewatering at all."
He said the contractor didn't originally apply for a permit to dewater from the ministry because initial drilling suggested it wasn't a problem. When the work advanced past the first 200 metres that's when it started to become an issue.
"The test pits did not have that much water," said Daniel. "That's why they decided to start the project without a permit from the MOE."
Daniel said the city has had previous experience dealing with projects that are building close to the water table in areas like Eastbridge and Laurelwood.
"Our experience is that the water table will be coming back in a day or two," said Daniel. "We have a hydrologist checking that and monitoring that, and we have three flow monitors installed along the Environmental Sensitive Protected Area.
"The maximum area it is going to affect is 20 to 30 metres from the site. That's the maximum area. It's not going to affect 100 metres away from the centre line of the well-point system."
Daniel said some of the concerns, especially about the stormwater ponds rising beyond acceptable levels, aren't accurate.
"Not that much water is coming out," he said. "It's totally exaggerated."
But at least one city councillor is concerned.
"I am always concerned when we put a sewer pipe to nowhere," said d'Ailly.