Updated December 15, 2020

The City of Toronto has completed a Municipal Environmental Assessment (EA) Study to achieve the following for the Black Creek Sanitary drainage area:

  • accommodate flows for projecting 2041 population and employment growth and beyond
  • reduce surcharge levels the Black Creek Sanitary Trunk Sewer (STS) during wet weather events
  • reduce combined sewer overflows (CSO) discharge to the Black Creek watercourse
  • reduce stormwater infiltration and inflow into trunk sewers

The following are key study recommendations:

  • implement Wet Weather Flow reduction measures along the existing Black Creek STS
  • install two new sanitary trunk sewers and a new combined storage tank and tunnel in the vicinity of Rockcliffe Court
  • complete sewer upgrades along Keele Street between Eglinton Avenue West and Donald Avenue

Study Links

This study is expected to complete in 2020, with design and construction schedule after 2025.

To receive a high resolution copy of the latest materials or require assistance in reading these files, please email or call the staff contact.

Area Map of the Black Creek Drainage Improvement Study

Black Creek STS Study Area Map
Black Creek STS Study Area Map

Built around 1960, the Black Creek Sanitary Trunk System (STS) is a 15 km long sanitary trunk sewer that services the 5,500-hectare drainage area.  The trunk system ultimately flows to the Humber Wastewater Treatment Plant.

During major storms, flows in the trunk system exceed the design capacity. This has caused overloading and surcharging. Also, during some storms, overflows area released from the combined trunk sewers to the Black Creek watercourse, which need to be controlled according to the Ministry of Environment, Conservation and Parks’ criteria.

Over the next few decades, a population and employment increase is expected within the study area, which will need to be accommodated by the trunk system.

Three rounds of Public Consultation Drop-In Events will occur for this Class EA Study project.

  • The first event took place in April 2016.
  • The second event was on April 4, 2019, at the Falstaff Community Centre.
  • The third event was on December 11, 2019, at the Falstaff Community Centre.

Study overview

In 2015, the City of Toronto has initiated a Municipal Class Environmental Assessment (EA) study to address problems and opportunities with the Black Creek Sanitary Trunk Sewer (STS) within study area.

The purpose of the Class EA study is to assess capacity issues of the Black Creek STS and to develop a plan to:

  • ensure the trunk sewer system has capacity to service future population and employment growth
  • better manage flows in the trunk system during rainfall events
  • reduce combined sewer overflows to Black Creek watercourse
  • reduce stormwater entering the trunk system

The Process

The study is being planned as a Schedule “C” project under the Municipal Class Environmental Assessment document. The Class EA process provides members of the public and interested parties with opportunities to provide input at key stages of the study. The studies will define the problem and the causes of the problem, consider and evaluate alternative solutions, assess impacts of the preferred solutions, and identify measures to lessen any adverse impacts.

What is a Class Environmental Assessment?

Ontario’s Environmental Assessment (EA) program promotes good environmental planning by determining and managing the potential effects of a project prior to implementation.

The EA program ensures that public concerns are heard. EA balances economic, social, cultural and natural environmental needs so that projects benefit Ontario.

This study is being carried out according to the Municipal Class Environmental Assessment process. This is an approved approach to satisfying requirements of the Environmental Assessment Act specifically tailored to municipal infrastructure. The process includes identifying the problem or opportunity to be addressed, developing and evaluating a range of alternative solutions, providing opportunities for public input and identifying a preferred solution.