North Huron council updated on progress of floodplain mapping by Maitland Conservation

·3 min read

NORTH HURON – Maitland Conservation (MC) updated North Huron council recently on the progress of the floodplain mapping project currently being undertaken in North Huron and Morris-Turnberry.

Steve Jackson, MC’s flood and erosion safety services coordinator, made the presentation, giving council a timeline of activity.

Jackson explained that the project is delayed by about six months, mainly due to COVID-19 and the public information centre’s postponement.

The map is defined by a single significant event, in this case by Hurricane Hazel. This catastrophic storm happened in Southern Ontario in 1954.

Jackson told council that the province directed them to plan the map as if Hurricane Hazel happened right over Wingham to gauge what type of flooding could be caused.

He added that a flood of this magnitude has never happened in this area.

The last time floodplain mapping was updated was in 1978.

In the fall of 2018, the National Disaster Mitigation Program approved funding for the project. In early 2019, Light Detection and Ranging (LiDAR) was flown over the area.

LiDAR is a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variable distances) to the Earth, according to the National Ocean Service. These light pulses, combined with other data recorded by the airborne system, generate precise, three-dimensional information about Earth’s shape and its surface characteristics.

The project was awarded to GeoProcess Research Associates in July 2019, and the fieldwork was completed in the fall of 2019.

The fieldwork included surveying bridges and checking depth levels in the rivers and other waterways.

Engineering was completed in January 2020, and the public information centre was delayed but has recently been completed, Jackson said.

He was impressed by the amount of detailed feedback they received by holding the public information centre by appointment, saying that “a lot of times in public information centres it’s difficult to have really detailed conversations with people,” speaking of in-person meetings.

“One of the advantages of setting up appointments and doing this over three days is that you get to spend a fair bit of time with all the property owners in the area and really understand their concerns and have more time to address them,” he said.

The MC board approved the mapping in January 2021, except for one property in Morris-Turnberry.

Several new areas in North Huron were identified and included in the new floodplain map, and some areas were removed.

Jackson responded to questions about the effects of the Howson Dam removal and showed a model comparing the floodway with the dam and without, remarking that “there are significant portions of the floodway in Morris-Turnberry that are a direct result of the Howson Dam (based on the model).”

The plans are to meet with municipal staff from North Huron and Morris-Turnberry and develop a series of maps that show flood inundation at various levels.

This mapping will identify road closures, evacuations and critical infrastructure that would be included in the Municipal Emergency Plan.

“Boots on the ground would already have maps prepared that show where that flood will progress,” Jackson said, adding that knowledge would help them to get to the most at-risk people and places first.

Cory Bilyea, Local Journalism Initiative Reporter, Wingham Advance Times