MINTO – Town council has authorized staff, consulting engineers and the Maitland Valley Conservation Authority (MVCA) to continue with a Harriston flood mitigation study for presentation to the public and council in the fall.
In a resolution at the June 18 meeting, council also directed that individual projects to improve flood conditions proceed as soon as the budget and approval process allow.
Acting CAO Chris Harrow told council the town, along with Triton Engineering and the MVCA, are “all working together on this to help with the Harriston flooding issues.”
“We all remember it – June 23, 2017, the seven inches in seven hours that fell and the flooding that we had … that was our one-in-100-years event,” said Harrow.
Since the flood, which caused major damages to homes, businesses and municipal facilities in Harriston, Harrow said, “We have done a lot of work and we have been continuing to push forward.”
Harrow pointed out aerial photography and digital mapping have been completed.
“Maitland Valley has done some phenomenal modelling to be able to tell us exactly where the floods came from and how it affected different communities,” Harrow explained.
“But even better, with the modeling, is any work that we do, they can run the model before we do the work to show us how much that work is going to improve on the flooding.”
For example, Harrow noted downstream work done to remove trees and shrubs along the river bank and clearing the North Ward Drain outlet has been run through the modelling process.
“We’ve already seen what that’s going to do and how much that’s going to help with the flooding,” he said.
Harrow added that keeping the North Ward Drain outlet on the southwestern side of town is key to flood mitigation efforts for the northern portion.
“To keep it simple … there’s a great big pipe under there that goes from the north end of George street all the way under the town and comes out near Speare Seeds and that helps drain that whole area, and by clearing that outlet we can let the water get away quicker,” he pointed out.
At a Nov. 27, 2018 public meeting the MVCA presented 14 potential scenarios to reduce flooding.
The most drastic, with a potential cost upwards of $25 million, was to fully divert the Maitland River around Harriston. Less costly work such as downstream floodplain channelization was also presented.
Harrow said council was asked for direction on how flood planning should proceed, based on a report from Triton Engineering senior planner Bill White.
The report notes three potential options;
– watershed planning using 2018 draft guidelines consistent with the Growth Plan for the Greater Golden Horseshoe;
– a Class Environmental Assessment process under the Environmental Protection Act; or
– a flood mitigation plan.
Harrow explained the flood mitigation plan was the recommended option, as the other two would be time consuming and costly.
“When we talk about moving the river, as people have talked about, and redirecting the river so it doesn’t come into Harriston, that is a very expensive process to do that, obviously, between land acquisition and digging and all that stuff; but not only that, to do an Environmental Assessment on that entire process would be very time consuming, very expensive and we might not ever use it,” he said.
“So what we’re recommending is we don’t go down that road right now; we work on the downstream stuff, we see how the modelling reacts to it and how we can affect the flooding … and that keeps us away from us having to do any Environmental Assessments at this time.”
“I agree with the process,” said deputy mayor Dave Turton.
He noted his discussions with MVCA officials indicate “with what we’ve done we’ve already taken some good steps.”
Harrow said the town, with assistance from Triton and the MVCA, can come up with a flood mitigation study to be presented at a public meeting in October. Meanwhile, mitigation projects can proceed as approved and funded.
The report notes the town has received two grants under the National Disaster Mitigation Program.
The program funds up to half of eligible costs for risk assessments, flood mapping, mitigation planning and investments in small scale mitigation work. The Town’s 2019 budget includes $262,300 for this work, 50% funded by the grant.
Council received the report and directed staff, the MVCA and Triton to continue with the Harriston Flood Mitigation Study.
It is to be presented to the public and council in the fall.
Town council also authorized individual project work to improve flood conditions, subject to the town budget and any approvals that are required.
