P.E.I. creates inland flood maps to mitigate risks

P.E.I. is developing inland flood maps of Charlottetown and Summerside to identify and mitigate risks of destructive rainfall events predicted as climate change progresses. But plans to map other municipalities are not finalized and rural regions are not on the federally cost-shared project agenda.

“We expect to see an increasing number of heavy rainfall events, like the one that took place in Nova Scotia recently,” said Peter Nshimura, manager of the Climate Action Secretariat for the provincial Department of Environment overseeing map development.

In late July, 52-year-old Nicholas Holland as well as two six-year-olds, Natalie Harnish and Colton Sisco, died in Nova Scotia floods when water quickly submerged their vehicles.

“These maps will help us to be better prepared for events like that,” he said.

Inland flooding is a priority climate hazard, according to P.E.I.’s 2021 Climate Change Risk Assessment which reports an annual four per cent chance P.E.I. will experience a rain event so severe it could cause $10 million to $100 million in agriculture, aquaculture and fishing industry losses.

A storm like this is forecast to cause major infrastructure damage and could disrupt utilities including safe drinking water for weeks. It is predicted to cause broader issues that could lead to injury, disease, hospitalizations or possibly death affecting 10 to 100 people.

The risk of a severe rain event directly causing a death is low on P.E.I., according to the report, but not negligible.

As climate change progresses an event this severe is forecast to double in annual likelihood to 10 per cent by 2050. This means it will be expected to happen once every 10 years, compared to once every 25.

“The most important thing is people’s lives,” said Adam Fenech, associate dean of the School of Climate Change and Adaptation at the University of Prince Edward. While the urban maps are a step in the right direction, he said, an Island-wide map would be most beneficial.

It could help identify areas where emergency response routes are likely to be compromised by severe rain. It could also allow Islanders to identify and mitigate risks to their property and follow well-informed emergency plans.

Rimsha Khan is a climate action specialist with the Federation of Agriculture. She said detailed inland flooding maps would be useful for farmers too.

“Not everybody knows every inch of their land or what areas are going to be affected more by inland flooding, so definitely, it would be a big help,” she said. “With a map we can plan and design effective drainage systems and decide where to plant and put fertilizer.”

Drainage systems prevent crops from being destroyed and quality soil and fertilizer from going to waste or damaging aquaculture and fishing environments.

Khan said farmers have already been dealing with more intense rain events and there is a need for solutions.

“We’ve seen instances this year where there has been like just a ton of rain in just five minutes,” she said.

On July 3, in Charlottetown 59.9 mm of rain fell over the course of the day and September 15 up to 50 mm fell, said Jim Prime an Environment Canada meteorologist providing examples of heavy rain days this year. If the one in 25 year rain event described in the Island’s climate assessment materializes, 100 mm of rain or more would fall over the course of 24 hours.

Depending on the region, 100-250+ millimetres of rain fell within 24 hours in Nova Scotia in July this year contributing to the historic and fatal floods.

Rachel Collier is a Local Journalism Initiative Reporter for The Eastern Graphic.