Revealed – most flood-prone cities in Ontario

Revealed – most flood-prone cities in Ontario | Insurance Business Canada

Catastrophe & Flood

Revealed – most flood-prone cities in Ontario

Study also looked at government funding allocation

Catastrophe & Flood

By
Terry Gangcuangco

A new study by insurance comparison platform MyChoice has identified the areas in Ontario that are most vulnerable to flooding. The research also examined current and planned infrastructure projects aimed at mitigating flood risks and enhancing preparedness throughout the province.

The analysis drew on the flood susceptibility index dataset, which is made available by the Government of Canada, Natural Resources Canada, and the Strategic Policy and Innovation Sector. By processing the coordinate data from the dataset, the study pinpointed the cities in Ontario most at risk.

The research accounted for a broad range of factors, including meteorological conditions like daily precipitation and annual rainfall, hydrography such as proximity to rivers and drainage density, as well as geological and ecological factors like land use and soil moisture. Terrain characteristics, including slope and elevation, and urban infrastructure like road density, were also analyzed.

Each city in Ontario was assigned a flood risk score on a scale from 1 to 5 based on the analysis. The research then calculated the extent and concentration of high-risk zones within these cities. Cities such as Ajax (4.6), Ottawa (4.5), Mississauga (4.4), and Toronto (4.3) emerged as the most flood-prone areas in Ontario, with a notable cluster of at-risk municipalities located in the Greater Toronto Area and Eastern Ontario.

These cities share characteristics such as dense populations, significant infrastructure, and growing urbanization, which contribute to their heightened flood vulnerability. Additionally, Brampton (4.3), Brantford (4.2), and Vaughan (4.2) also showed high flood risk scores, underscoring the widespread nature of the flood threat across the province.

City

Flood risk score

Ajax

4.6

Ottawa

4.5

Mississauga

4.4

Toronto

4.3

Brampton

4.3

Brantford

4.2

Vaughan

4.2

Sarnia

4.1

Markham

3.9

Lakeshore

3.9

Brockville

3.8

Belleville

3.8

Oshawa

3.7

St. Catharines

3.7

Caledon

3.7

Kingston

3.6

Burlington

3.6

LaSalle

3.5

Windsor

3.4

Peterborough

3.3

MyChoice’s team reviewed current and upcoming climate resilience infrastructure projects in Ontario, focusing on stormwater management, flood defences, and emergency preparedness in flood-prone regions. The study assessed whether the government’s allocation of funding and resources aligns with the high-risk areas identified.

While cities like Toronto, Ottawa, and Mississauga, which were identified as having significant flood vulnerabilities, are receiving considerable investment in flood defence and mitigation projects, other high-risk areas like Ajax and Brampton appear to be receiving less attention.

The discrepancy suggests that while the government’s response is generally aligned with the identified risks, there may be gaps that need to be addressed to ensure comprehensive flood protection across all high-risk zones.

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