Project Overview
The City of Toronto, together with Toronto and Region Conservation Authority (TRCA), have initiated a Municipal Class Environmental Assessment (MCEA) to determine a preferred riverine flood mitigation strategy for the Rockcliffe-Smythe neighbourhood.
This study will build upon recent advancements in the understanding of the causes of flooding within the community. Completion of the MCEA is the next step necessary to meet regulatory requirements prior to construction.
The primary objectives of the riverine flood mitigation strategy are:
- To minimize riverine flood risk in the Rockcliffe-Smythe neighbourhood to the extent practical
- To develop robust and low-maintenance flood mitigation solutions
- To minimize and mitigate potential impacts resulting from the implementation of flood mitigation solutions
- To coordinate riverine flood mitigation designs with concurrent transportation, sewer, and drainage projects in the study area
Frequently Asked Questions:
Public Information Centre #1 – June 16, 2021
Q. Will this project stop my basement from flooding?
A. While this project addresses riverine flooding and not specifically basement flooding, it will reduce the risk of basement flooding. In some areas this project will achieve the targeted 100-year storm event level of protection from urban flooding. In some other areas, such as along Hilldale Avenue, sewer upgrades will also be required to achieve the full level of urban flooding risk reduction.
Q. How will Smythe Park be impacted by the flood mitigation project?
A. Alternative #1 has significantly fewer impacts to Smythe Park than alternatives #2 and #3. With alternative #1 there are no anticipated permanent, widespread impacts to the baseball fields or the pool. There may be some isolated short-term impacts related to construction access that will be identified and addressed during the next phase of the EA. The project team has heard very clearly from the community that the Smythe Park recreational amenities are very important to the community.
Q. Instead of making the channel wider can you just make it deeper?
A. The proposed alternative solutions include the maximum possible depth for the channel. The channel cannot be made any deeper than Black Creek channel at the downstream (west) end of the construction area in order for water to continue to flow into the unmodified portion of Black Creek and to the Humber River.
Q. Are you able to make the channel look like a “natural” channel similar to the main Humber?
A. The current designs allow for some elements of naturalization to the extent that it is safe to do so. While the modifications may improve the conditions for natural features relative to what is currently there, the large amount of fast-moving water in the creeks during storms has high erosion potential, which limits the extent of naturalized elements as they can be washed away. Options for naturalization will be reviewed further for feasibility and impact during the design concepts phase once a preferred alternative solution is selected.
Q. Can you also protect Smythe Park from flooding?
A. Smythe Park is located within the bottom of the creek valley system and so is within the natural floodplain of the creek. The park is currently at risk of flooding during larger storm events and will continue to be at risk of flooding after the proposed solution is implemented. Given its location within the natural floodplain it would require extraordinary measures to protect it from flooding.
Q. Can the amount of concrete used be reduced? Can it be permeable (to allow water to soak through)?
A. The extent to which the channel can be naturalized will be examined in the next phase of the Environmental Assessment.
We are working within some constraints, such as the fact that the roughness of the channel surface directly affects the ability of the channel to convey water quickly in a flood situation. As a result, a naturalized channel will have higher water levels during a flood in comparison to a smoother channel (such as exists now). Our preliminary assessments indicate a 1.5 m higher water level in a naturalized channel in comparison to a smoother engineered channel. Therefore, a fully naturalized channel would significantly reduce the flood reduction benefits or would need to be much larger to convey the same amount of water.
Another important consideration is the erosive power of flood waters. Flow in the Black Creek channel has a lot of energy, which would cause significant channel erosion if the channel was naturalized. Significantly more land would be required to create a naturalized channel with meanders, pools, and other energy dissipation features. A permeable channel surface would not assist with providing flood mitigation as the volume and speed of water during a flood event far exceeds what could soak through a permeable channel surface.
That said, all efforts will be made to naturalize the channel as much as possible in the next phase of the Environmental Assessment. The study team will strive to develop a design that considers aesthetics, terrestrial and aquatic habitat, and maintainability, among other factors, while ensuring flood protection is not compromised.
Q. Will wildlife and trees be removed?
A. The purpose of this study is to reduce the risk of riverine flooding for this area. Trees located within the new channel footprint will be removed. New trees will be planted to compensate for removed trees in accordance with the applicable City of Toronto bylaws and TRCA policies and guidelines. Opportunities for improvements to the area, such as improved terrestrial and aquatic environments, are being explored while ensuring the primary objective of riverine flood mitigation is still achieved.
Q. Can anything be done upstream to reduce the high flows to this area?
A. Through the Environmental Assessment process, we look at a number of different ways in which the project objective (of providing flood protection for the area) can be achieved. The process starts with a long list of options that could potentially provide flood protection for the area. Any options on this list that do not provide adequate flood protection or are not feasible to implement are screened out.
Upstream flow diversion, reduction of flows, and upstream storage of water were all assessed and screened out. The three alternatives presented at the Public Information Centre are those that best meet the project objectives of providing flood mitigation throughout the study area with robust and low-maintenance flood mitigation solutions while being mindful of the existing environment and infrastructure.
Q. How is the sewage overflow in the creek being addressed?
A. With respect to discharge from the combined sewer system, none of the proposed alternatives would increase combined sewer discharges to the Black Creek watercourse. Toronto Water is currently undertaking parallel projects that would reduce combined sewer discharges to the watercourse. Please visit toronto.ca/blackcreekstudy for further information.
Frequently Asked Questions:
Public Information Centre #2 – March 1, 2022
Q. Will Scarlett Road bridge be built before Jane Street bridge?
A. In future stages of design work, a detailed implementation plan will be developed to determine the phasing and timing of construction for all components of the proposed solution, including the expansion of the Scarlett Road bridge. The development of the implementation plan will include examining current flood risks and potential adverse impacts on the community as the solution is being constructed. The plan will also consider higher areas of flood risk, assign priority to the most vulnerable properties in the community, and ensure there are no significant adverse impacts in any interim scenario.
Q. How will green space, vegetation, and trees be protected?
A. The preferred solution for the project will limit impacts to green space, vegetation, and trees to the extent practical, while also adequately addressing riverine flooding in the area and limiting other adverse impacts to the community, private properties, and infrastructure. Additional field studies will be conducted during the detailed design phase to inventory trees and further develop plans to minimize impacts to greenspace and restore trees or vegetation. Plantings around the channel and private property to improve aesthetics and privacy (referred to as “screenings”) will also be considered.
Q. Will the width of the trail along Lavender Creek decrease?
A. The Lavender Creek trail that runs east-west from Gunns Road to Symes Road will remain intact and the width of the trail will not be reduced. The Lavender Creek trail that runs south-north from Symes Road to Hilldale Road is an informal trail. New trails are out of scope of the study, but we are ensuring the space required for a formal trail in this location is available in the future.
Q. What will be done to protect residents during the flood mitigation construction process?
A. Mitigation plans will be prepared to minimize and monitor impacts where possible. Following the environmental assessment, detailed design work will include more information on construction staging and what can be expected for the duration of construction. During construction, there will be an identified contact number for residents to discuss construction impacts or issues that need to be addressed as the project unfolds.
Q. How is this project being funded?
A. The City applied for Disaster Mitigation Adaptation Funding (DMAF) in October 2021, which is a request at the federal level for cost-share funding for the entirety of the project. The Jane Street bridge and Symes Road culvert already have approved federal and/or City funding. The City is continuing to search for funding opportunities, including Provincial infrastructure funding.
Q. What is the timeline for this project?
A. This is a very complex project with multiple parts. A project of this scale requires significant funding and will be implemented in phases. The preliminary construction schedule for the riverine flood mitigation works will have construction complete as early as the end of 2032, if fully funded. There are large underground services and utilities that require significant coordination and planning to ensure the planned road and flood protection works can begin.
PLEASE NOTE: Even though Basement Flooding Protection Projects (BFPP) and proposed riverine flooding mitigation infrastructure is hydraulically inter-connected, the 10-year project timeline for the riverine flood mitigation works does not delay the BFPP projects in this area. BFPP project works in the Rockcliffe area are scheduled to begin construction in 2027.