Like many communities in southern Ontario, including London, Mississauga, and Toronto, the Municipality Middlesex Centre experienced flooding following significant and intense rainfall events during the week of July 14. The following provides a brief overview of the rainfall event, its impacts, and the municipal response to date.
Significant Rainfall Event
Following significant rain from the remnants of Hurricane Beryl during the week of July 8, southern Ontario including Middlesex Centre saw significant rainfalls July 14 to 16.
- Environment Canada reports show that London received 104 mm of rain on just July 15 and 16, days, compared to a usual average of around 55 mm for the entire month of July.
- The Upper Thames River Conservation Authority (UTRCA) reported that their watershed received between 75 mm and 175 mm of rain over the past week.
- The Ausable Bayfield Conservation Authority (ABCA) reported that the Nairn area received between 120 mm and 150 mm on just July 16, and rains continued after the message was released at 5:00 pm.
Between 8:00 am and 9:30 am on July 16, the rain came as torrential downpours over this very short period of time. Staff are still collecting rainfall data, but it is believed that the intensity of the storm over this brief period of time exceeded a 1-in-100-year storm in some areas of the municipality.
The amount of runoff generated was compounded with the intense rainfall adding to ground which was already saturated from previous rains on July 15 and early on the morning of July 16. The result was an unprecedented amount of runoff and flooding including in areas where flooding has not typically been seen and levels of flooding in some low-lying areas not previously recorded.
Flood Event & Municipal Infrastructure
The municipal underground system (stormwater, culverts, etc.) is not designed to handle rainfall of this intensity, and as a result we experienced surface flooding which is normal and expected under severe storm events. Surface flooding is intended to be temporary until the runoff is transported by either:
- the underground storm sewer system, or
- by overland flow routes on the surface of the ground that typically follow roadways, rear yard swales and walkways as well as other designed locations.
While flooding affected the entire municipality, the worst of the situation seems to have occurred in the northern portion of the municipality, including Ilderton and Arva.
- There have been numerous reports of flooded basements due to sump pumps that could not keep up with the inflow and reports of temporary surface flooding.
- Generally speaking, municipal infrastructure functioned well under these extreme conditions. Staff are accessing infrastructure for damage and collecting data for future use (asset management, identification of flood risk areas).
Updates on Municipal Services
- Flood Alerts: All five local conservation authorities with jurisdiction in Middlesex Centre issued flood bulletins, ranging from water safety messages up to flood warnings. Conservation authorities continue to remind people to stay far away from waterways as the high, fast flows pose a significant safety risk.
- Road Closures: Middlesex Centre staff have been closing local roads due to flooding and culvert failures. More than 15 road closure events occurred between July 15 to today (July 17). Road closures continue as the runoff makes its way downstream causing streams to overflow their banks and staff undertake necessary repairs.
- Sports Field Closures: Middlesex Centre staff closed all soccer and baseball fields on July 15 and 16 due to the field conditions. Most fields reopened as of July 17 (exclusions: Denfield baseball diamond and Heritage Park baseball diamond #2 and the t-ball diamond).
- Extended Waste Drop-Off at Enviro Depot: Residents with flood-related garbage may bring it to the Denfield EnviroDepot free of charge this coming weekend July 20 (depot hours extended to 8:00 am to 6:00 pm) and the weekend of July 27 (normal hours). .All other normal rules and rates apply.
- Actions by Residents: Council and staff would like to extend a big thank-you to all the residents who assisted in picking up garbage and recycling and clearing catch basins grates, as well as helping their neighbours. We appreciate the kind and caring nature of our neighbourhoods and community!
We would ask that residents continue to check the catch basins near their homes and clear any materials that may be blocking the grate. If the grate cannot be easily cleared, residents are asked to contact the office to let staff know, including leaving the location of the grate in the message.
Residents should continue to monitor their sump pump and the grading around their property to ensure both are working to move water away from their foundation. More information is available on the website.
Sharing Information
Details about Middlesex Centre’s flood event were shared with residents through response to phone, email and web-based inquiries by staff, messages to affected groups (such as emails to baseball teams about field closures), and through the following:
- Website – Municipal alerts are posted along the top Middlesex Centre website and are updated as new information is available.
- Social Media – Key information (closures, etc.) continues to be shared on Middlesex Centre’s Facebook, X, and Instagram pages.
- Municipal 511 – Road closures are posted on the Municipal 511 site, a link to which can be found on the municipal website.
- Reporting Concerns – Residents are asked to report any concerns to Middlesex Centre using the Report a Concern form found at the bottom of every website page (middlesexcentre.ca/report-a-concern) or to contact Public Works & Engineering.
Notifications will continue as appropriate.
Top Photo: Flooding on 9 Mile Rd.