Flood mitigation plan costs estimated at $40 M

MINTO – The total cost of measures to reduce or eliminate the chance of flooding to virtually all at-risk properties in Harriston could total around $40 million over 20 years, a draft study suggests.

Triton Engineering Services presented a draft Harriston Tributary Maitland River Flood Mitigation Study to town council at a Nov. 19 public meeting.

The study outlines 10 scenarios, ranging from a moderate flood channel downstream from town, to a complete diversion of the river around Harriston.

Triton senior planner Bill White told council the study’s focus has been narrowed to three of the 10 scenarios:

– a moderate flood control channel downstream of Harriston, from the Arthur Street bridge to Wellington Road 87 at a cost of $2.5 million;

– a major downstream flood control channel; hydraulic improvements in the urban areas and adding one metre of depth to the downtown conduit for $13.5 million; and

– diverting the river at the Blind Line flowing east of Harriston and connecting with Dredge Creek, and a farmland spill channel upstream of the town, at an estimated cost of $23 million.

While the total projected cost for all three scenarios exceeds $39 million, White noted the third option could include some portions of the other two projects, which would reduce the overall total.

He stressed the first scenario is the only one the municipality could consider financing on its own and suggested the town start looking for upper tier funding and private sector partnerships to help with costs.

“The flood mitigation study proposes practical corrective actions in a realistic 20-year funding plan the town and partners can implement to increase public safety and reduce property damage from flooding if flows were at Hurricane Hazel levels,” the report explains.

“Ten corrective scenarios were modelled and assessed based on cost, percent of properties removed from flood fringe, public disruption, nuisance, private land right obstacles and natural environment impact.”

The report continues, “The 20-year phase in cost of $39.58 million includes an estimated $580,000 for the Class EA process approvals. The total cost could be funded with no less than 35% federal government, 35% provincial government, 15% area property tax and area rating, 12% other potential public partners and 3% other revenue.

“The final flood mitigation study will be the document upon which funding requests can be made.”

White explained scenario one would remove about 25 properties from the flood fringe, while causing minimal disruption to the public and environment.

Scenario two would take about 200 properties out of the flood fringe, but would be highly disruptive to both the public and the environment.

Scenario three, the river diversion, would benefit nearly 250 properties, but comes at the highest cost in terms of dollars and public and environmental disruption.

White pointed out the town has a long history of flooding, with “about 15 flooding events in 100-plus years.

“So once every six or 10 years or so there’s events. 2017 was a one in one hundred year. That was a pretty severe event. 2018, just a few months after that, was a one -in-10-year event.”

White said the most extreme solution, the river diversion, would basically “take the flow of Hurricane Hazel, which is a lot more than we had in 2017, and take it around town,” he said.

That option includes an upstream spill channel that would mean building two new bridges on Highway 87.


The high end $40 million price tag would be an unprecedented expenditure for the municipality, said White.

“That’s lot of money … it would be the biggest capital project ever for the town.”

White laid out a timeline if all projects in all three scenarios were to proceed that would see scenario one completed within five years, the second scenario within 10 and the third and final stage completed in 20 years.

The downstream projects that involve “channelization” White noted, “would involve taking trees out.”

While stressing the plan would call for replanting efforts of “at least two or three to the ones that are lost somewhere else in the watershed,” White reminded council of the strong public reaction to recent flood mitigation efforts that involved cutting down trees along the river’s northeastern bank last year.

“I know it was heartbreaking for many people to see the trees that had to come out before … I don’t think you could go ahead with this without considerable public input,” he suggested.

Councillor Mark MacKenzie pointed out none of the scenarios under consideration removed from the flood zone properties in the southernmost corner of town, where considerable residential development is currently underway.

Maitland Valley Conservation Authority flood and erosion safety services coordinator Stephen Jackson told council that because the undeveloped land in question is in the flood plain, fill could be used to make it serviceable.

“Are we worried about downstream communities like Fordwich and Gorrie? Are we going to flood those people because we took care of our flooding?” asked councillor Ron Elliott.

Jackson said the design of the project would prevent that.

Mayor George Bridge said council shouldn’t let the cost deter them from dealing with the problem.

“I know the number looks big. But I guess, like anything else, you eat an elephant one little bite at a time and you can’t get scared away from a big project,” he said.

While noting, “you certainly do need the federal and provincial government,” Bridge pointed out, “according to everybody, nobody has any money – so we’ll see where it goes.”

“I think we committed a year or so ago that this council is serious about trying to do something,” said deputy mayor Dave Turton. “But I agree with our mayor that we certainly need the support from upper tiers.”

Turton said the 2017 flood, which caused millions in damage and led local officials to declare a state of emergency, brought home the potential for disaster.

“I think, also, some of us were sitting in the wings thinking what the hell is a 100-year flood? And we know what it is now. It’s kind of tough. We live on a river here in Harriston and there’s not much we can do about that.”

Triton officials anticipate finalizing the draft report in January, with a commentary period slated for February and final consideration by council in March.