overflow started at 5:43 a.m. and continued for 37 hours. The Emergency Plant By-pass was opened at 7:35 a.m. and effectively bypassed any excess flow to Pontiac Pump Station.

Pumping stations

All Pumping Stations operated without loss of service.

Retention Treatment Basin (RTB)

The Retention Treatment Basin operated as per design with no operational issues.

Contributing Factors

Contributing factors to the flooding which occurred include:

Detroit River – High Water Level

With record Detroit River levels as well as high levels in Turkey Creek and other drainage outlets to the river, the amount of storm relief that existed in the past is no longer available. River gates are unable to open as early as they have in the past. More combined sewage needed to be treated by the plant. The August 28th event saw significant overland flooding on the City’s West side. Overland flooding can further exacerbate the volume of flow directed to the plant as stormwater enters the sanitary system through manhole cover openings.

Herb Gray Parkway – Observed Blockage

While investigating the stormwater infrastructure within the City, it was discovered that a drain on the Herb Gray Parkway was partially obstructed. See Appendix C for a picture taken during the storm event showing the obstruction as well as a picture taken afterwards. While a blockage was observed, it is not currently known if or to what extent the blockage contributed to the flooding that occurred in Ward 1. Administration will be making the Parkway aware of this observation.

Climate Change

As a result of global climate change, extreme events including extreme precipitation and flooding have been occurring more frequently. These extreme events are expected to continue into the future.

Recommendations to Mitigate Future Risks of Basement Flooding:

Mandatory Downspout Disconnection

In order to reduce the amount of storm water entering the system in this neighbourhood, it is recommended that Council endorse the mandatory disconnection of downspouts within the area of the City hardest hit by flooding on August 28, 2020. The recommended area is that bounded by Norfolk Street to the North, Dougall Ave/Howard Avenue to the East and the Herb Gray Parkway to the West and South.