Rouge River Tributary 5 Environmental Assessment

The City of Markham is conducting a Schedule 'B' Municipal Class Environmental Assessment (EA) study for the Rouge River Tributary 5 watercourse. The study area is a key area for future development and, under existing conditions, the lands around the watercourse have potential flood risks during large storms. The purpose of this study is to assess potential flood mitigation and stormwater servicing for Tributary 5 of the Rouge River, and establish options to provide stormwater management solutions to facilitate future development of lands within the Markham City Centre.

The main Tributary 5 channel generally flows in a northerly direction and connects into the Rouge River. The project study area is primarily bounded the Metrolinx Rail corridor to the west, Highway 407 to the south, Kennedy Road to the east and just north of Unionville Gate to the north. Tributary 5 begins at the southeast portion of the study area at Highway 407 and connects to the Rouge River north of Unionville Gate. Please see the attached figure for the study area location.

Background investigations and assessments have been completed and will inform the development of the alternative solutions and selection of the recommended solution.

Get Involved

We value your input in the development of the optimal solution to address flooding concerns in the Tributary 5 study area. A pre-recorded virtual Public Information Centre (PIC) took place from February 25, 2025 to March 25, 2025. The City would like to thank the community for their participation in the virtual PIC.

The virtual PIC presented an overview of the study purpose, existing conditions, evaluation of alternative solutions, the recommended solution, and project next steps. The preliminary recommended option includes piping the majority of the channel to convey the regional storm flows. The fully piped option will remove flooding potential from virtually all of the Study Area, will open up the development potential of lands that are currently impacted by Tributary 5, and won't displace residents or businesses.

A virtual pre-recorded PIC presentation video was available for viewing and public feedback from February 25, 2025 to March 25, 2025. Feedback collected during the PIC period will be taken into consideration as the study moves forward. A copy of the PIC presentation slides have been provided on this webpage under the Documents tab.

A Notice of the pre-recorded virtual PIC was also sent to stakeholders and members of the public, and is also posted on this webpage under the Documents tab.

Other Ways to Get Involved

1. Stay updated: Save this website to your browser favourites.
2. Provide your feedback: Contact the Project Study Lead listed on the sidebar and provide your feedback or ask further questions you may have regarding the project.