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An environmental whistleblower says the city continues to ignore flooding dangers for the Kanata west development.
Ted Cooper, a water resources engineer with the City of Ottawa, says a third-party review of the 725-hectare development is flawed, failing to take into account a worst-case scenario for rainfall and possible flooding.
Work on the huge commercial, residential and office development was put on hold last year, over flooding concerns on lands near the Carp River.
City staff had discovered an error in the computer model used to calculate stormwater runoff for the project’s environmental assessment.
Ontario’s Environment Ministry later ordered a halt on all construction on the development pending a third party review of the project’s stormwater management plan.
The city hired Greenland International Consulting, which told councillors on April 9 that work on the development could proceed.
Greenland says the original computer modeling for stormwater runoff was off by 12 per cent, recommending developers provide 85,600 cubic metres of additional storage capacity for rainfall.
The consultant says the storage space will act as an insurance policy in the event of a worst-case scenario storm.
“That’s predicated on the design storm being the right one,” said Cooper, who originally worked on the project, until he was pulled from it by a city planning director.
Greenland calculated flood flows using a 12-hour soil conservation service (SCS) design storm, meant for rural watersheds, said Cooper – but the Kanata west development is urban.
Greenland should have used the 24-hour Chicago design storm, he said.
“The city’s guidelines state that the SCS storm is intended for rural watersheds,” he said.
Using the 12-hour design storm is inconsistent with the city’s position on development on lands near the Carp River, Cooper said.
In 2002, Glen Cairn residents launched a class-action lawsuit against the City of Ottawa for failing to provide necessary stormwater management improvements following a flood in 1996.
The city argued it relied on information provided by a consultant, who used the 12-hour design storm to calculate storm water runoff, when he should have used the 24-hour Chicago storm model, which is more appropriate for urban area, said Cooper.
Cooper presented his concerns to Greenland last October.
“They didn’t even consider any of it,” he said. “Rather than picking the 24-hour Chicago storm (model), they pick the one the city is suing their last expert for using.”
But there isn’t a big difference in the numbers using either model, said Don Moss, a water resources engineer with Greenland International.
“We philosophically disagreed with him and we ran it anyway (using the 24-hour Chicago storm model) and it’s all within one to two centimeters,” he said. “It’s not the catastrophic event that it’s painted out to be.”
Moss said Greenland International used the 12-hour SCS storm design model because a greater percentage of the affected area is in a rural area.
“The model of record includes a downstream area that includes a lot of rural area,” he said. “Ted is correct in what he is saying for smaller catchments in the top end, (but the) greater percentage (of affected land) is in rural form.”
Greenland International used every storm model “that’s ever been produced, including ones presented by the developers,” Moss added.
The engineer said Cooper’s concerns will be answered at the May 11 planning committee meeting.
“Ted has a tendency to go overboard,” said Kanata North Coun. Marianne Wilkinson. “He’s looking at a very rare occurrence.”
Wilkinson said the Greenland International report provides for a worst-case scenario by calling for developers to provide 85,600 square metres of storage capacity for excess rainfall – which could be made available by providing rain barrels to homes built in Kanata west, and using gravel on parts of parking lots and planting vegetation, which will absorb water and gradually release it into the Carp River.
She said the issues which created the Glen Cairn floods are totally different from the Kanata west situation.
“The Glen Cairn situation is totally separate,” she said.
Stittsville-Kanata West Coun. Shad Qadri said he is satisfied with Greenland International’s report.
“Based on that they’re suggesting we’re ok to move forward. I’m happy with the report recommending that the Kanata west lands are OK to move forward for development,” he said.
“This has gone two years now in terms of process,” said Qadri. “I’m sure the third party review has looked at those issues.”
Qadri said the flooding of Glen Cairn was a different scenario.
“Glen Cairn was dealing with water mains, water being pushed through drains rather than flowing water (as is the concern in Kanata west),” he said.
The Kourier-Standard repeatedly called Rob Mackay, manager of strategic projects for the city, for comment. He did not return phone calls.
CONCERNSCooper has a long list of problems with the third party review, including:
* It documents flood level increases of about 30 centimetres in the area of land between Palladium Drive and Hazeldean Road, resulting in flooding of private property.“Flooding of private property must be authorized by the consent of the affected property owners,” said Cooper.
“Here at the (Bell Sensplex), using their own calculations, water is going to back up,” Cooper said. “So people will be at an event, and you’ll have a big rainstorm, and you’ll come out and the parking lot will be full of water – and that could be polluted water.”
* The Kanata west plan allows for development on the fringe of the floodplain, by creating a modified zone. Normally, the city treats a floodplain as one zone and doesn’t allow any development, he said.“That’s the way it should be,” said Cooper. “The floodplain was drawn back in 1983 – you stay out of it.”
The city plans to change its official plan, allowing for a modified one-zone floodplain policy.
“They can’t use one zone and because they can’t use two zones, they’re going to invent a new kind of floodplain policy – and that will be challenged,” Cooper said. “In Ontario you’re supposed to use the preventative approach to floodplain management – you stay away from the floodplains.”
If the city moves ahead with the project, it will have to invest a lot of money in infrastructure, Cooper said.
“It will prove to be inadequate,” he said. “And, after the developers are long gone, just like in Glen Cairn, flooding will arise and the taxpayers will be left with creating the proper drainage system.”
Cooper said councillors are placing too much trust in the city’s approvals process.
“Councillors have been told repeatedly that everything is OK,” Cooper said. “And other people say everything is not OK. They’ve always gone with staff, but they’ve been proven wrong – so, finally, they want to hand it off to a third party review, and they’re just hoping that development can move forward, because they’re getting all kinds of pressure from developers, all kinds of pressure from people who want to move into their homes.”
Cooper will bring his concerns to a city planning and environment meeting on Monday, May 11.
“I think the prudent thing to do would be to ask the third party consultant to run the design storm that they found to be critical in Glen Cairn and to have the design of the drainage system in Kanata west consistent with the standard used in Glen Cairn that the taxpayers paid for.”