Ashbridges Bay/Coatsworth Cut Erosion Control Project
ASHBRIDGE’S BAY/COATSWORTH CUT
CLASS ENVIRONMENTAL ASSESSMENT
(ABCC Class EA)
Study Area
Ashbridge’s Bay is located on the north shore of Lake Ontario in Toronto, Ontario. Within the local study area, Coatworth Cut serves as an access route to the lake for several boat clubs, and a public boat launch, and offers sheltered water for sailing, kayaking, and canoeing. Lands surrounding the local study area include Woodbine Beach, Ashbridge’s Bay Park, Tommy Thompson Park, and Toronto Water’s Ashbridge’s Bay Wastewater Treatment Plant.
Background
Following construction of Ashbridges Bay Park in the mid-1970s, sediment eroding from the Scarborough Bluffs was transported westward and deposited in the eastern embayment creating a large beach. As the embayment filled in, a sandbar began to form offshore, causing the sediment to bypass the park. In 1999, Baird and Associates estimated 10,000 m3 of sediments are transported, around the Ashbridges headlands on an annual basis. Particle tracking indicates that most of this sediment is deposited in front of the Ashbridge’s Bay Wastewater Treatment Plant, with some 2,000 m3 making its way into the entrance of Coatsworth Cut.
Toronto and Region Conservation (TRCA) currently maintains navigation and recreational opportunities in Coatsworth Cut. In 1983, TRCA began dredging operations at Coatsworth Cut to maintain the navigation channel. Ever increasing dredging volumes and associated expenses prompted TRCA to investigate a more permanent solution. In 2002, TRCA initiated a Class Environmental Assessment (EA) to remediate navigation hazards resulting from the deposition of sediments in Ashbridge’s Bay/Coatsworth Cut. The EA explored all reasonable and feasible alternative solutions to address the problems associated with the Coatsworth Cut navigation channel (See Figures 1-6). The alternative solutions were evaluated, considering the positive and negative impacts on the existing physical, biological, socio-economic, and cultural environments, as well as technical concerns, cost and feasibility.
Based on the results of the evaluation, Option 2a was selected as the preferred approach. As outlined in Figure 4, this option proposed a 600 m breakwater south of the Ashbridge’s Bay Water and Sewage Treatment Plant, a 100 m breakwater west of the treatment plant overflow gates and an extension of one of the headlands at Ashbridge’s Bay Park.
Figure 1 Plan showing Alternative 1
Figure 2 Plan showing Alternative 1A
Figure 3 Plan showing Alternative 2
Figure 4 Plan showing Alternative 2A
Figure 5 Plan showing Alternative 3
Figure 6 Plan showing Alternative 4
On November 7, 2002, TRCA hosted a public open house to receive feedback on the preferred alternative. During the public meeting, concerns about water quality were raised in connection with the ‘Learn to Sail’ programs, which operate in Coatsworth Cut. It was raised to the attention of TRCA that the City of Toronto had adjusted the 25 Year Implementation Plan for the Wet Weather Flow Management Master Plan (WWFMMP) to make provisions for additional storage and treatment of stormwater discharging into Ashbridge’s Bay/Coatsworth Cut. TRCA committed to assess the potential impact of the proposed breakwater on water quality in Ashbridge’s Bay and to determine what if any implications the City of Toronto’s proposed water quality improvements may have on TRCA’s project.
TRCA completed a detailed water quality study to assess the potential impact of the preferred alternative using the same numerical model used in the development of the WWFMMP. The results of this modeling indicated that based on the existing conditions the creation of the proposed breakwater would increase bacteria concentrations, turbidity and nutrient loading in Ashbridge’s Bay/Coatsworth Cut.
At this time, TRCA also learned of other proposed projects within the Ashbridges Bay area, which could potentially affect the TRCA's work including the construction of a new outfall for the Toronto Water’s Ashbridges Bay Treatment Plant and the initial development stages of a Master Plan for Lake Ontario Park led by the Toronto Waterfront Revitalization Corporation (TWRC), now known publicly as Waterfront Toronto.
Based on these issues, TRCA staff decided to suspend the Class EA until the parallel planning initiatives by Toronto Water and Waterfront Toronto were completed.
In November 2007, the Toronto Water completed a Municipal Class Environmental Assessment for the Coatsworth Cut CSO and Stormwater Outfalls Control. The preferred solution includes source and conveyance controls throughout the sewershed as well as a 10 ha treatment wetland, proposed south of the treatment plant (see Figure 7). The Environmental Study Report prepared in support of this EA, also however noted the need to coordinate design of the wetland in tandem with Waterfront Toronto’s plans for Ashbridge’s Bay as per the Lake Ontario Park Master Plan.
Figure 7 Municipal Class EA for the Coatsworth Cut CSO and Stormwater Outfalls Control Preferred Alternative
Lake Ontario Park (LOP), as envisioned by Waterfront Toronto, is a waterfront park spanning from Cherry Beach in the west to the R.C. Harris Filtration Plant in the east. This large-scale Park, will include the Ashbridge’s Bay shoreline to achieve the goal of restoring a wetland complex originally found in the area. According to the LOP Master Plan, the location of the proposed wetland is in Coatsworth Cut, rather than south of the Ashbridge’s Bay Wastewater Treatment Plant.
Since the Lake Ontario Park Master Plan was released at the end of 2008, TRCA, Toronto Water, and Waterfront Toronto have agreed to work cooperatively to achieve Waterfront Toronto’s vision for Ashbridge’s Bay Park and Coatsworth Cut. On May 13, 2009, Waterfront Toronto received Board approval to proceed with Phase 1 of Lake Ontario Park (see Figure 8), which includes construction of a new landform at Ashbridge’s Bay Park to facilitate relocation of the boat clubs currently located in Coatsworth Cut to the boat basin currently occupied solely by Ashbridge’s Bay Yacht Club. The pedestrian connection between Tommy Thompson Park and Ashbridge’s Bay Park, as well as the 1200m x 90m rowing channel outlined in Figure 8 are not part of Waterfront Toronto’s approved scope of work. 
Figure 8 Ashbridge’s Bay Park conceptual plan as per Lake Ontario Park Master Plan
As part of this partnership, TRCA has been requested by Waterfront Toronto and the City of Toronto to reinitiate the Conservation Ontario Class Environmental Assessment (Class EA) for the Ashbridge’s Bay/Coatsworth Cut Erosion Control Project. TRCA will undertake the ABCC Class EA to identify a preferred alternative from an expanded list of alternatives,that will address the existing navigation risk caused by sediment deposition at the harbour entrance of the Ashbridge’s Bay headland, thereby reducing the need for maintenance dredging on an annual basis. It is anticipated that an Environmental Screening Report will also be required to address Federal Environmental Assessment considerations.
WHAT’S NEW
NOTICE OF RECOMMENCEMENT August 2009
Toronto and Region Conservation's Ashbridge's Bay/Coatsworth Cut Erosion Control Class Environmental Assessment
PROJECT ARCHIVE
NOTICE October 2004
Toronto and Region Conservation's Decision to Suspend the Ashbridges Bay/Coatsworth Cut
Erosion Control Class Environmental Assessment
NOTICE October 2004:
October 2004
NOTICE
Toronto and Region Conservation's Decision
to Suspend the Ashbridges Bay/Coatsworth Cut Erosion Control
Class Environmental Assessment
On November 7, 2002 Toronto and Region Conservation hosted a public open house regarding the Class Environmental Assessment to remediate navigation hazards resulting from the deposition of sediments in Ashbridges Bay/Coatsworth Cut. The purpose of this open house was to present the revised preferred concept for Option 2a and to receive public questions, comments and concerns. The preferred concept included a 600 m breakwater south of the Ashbridges Bay Treatment Plant, a 100 m breakwater west of the treatment plant overflow gates and an extension of Headland C at Ashbridges Bay Park.
A local community member in attendance at the open house identified that he had attended the City of Toronto's Wet Weather Flow Management Master Plan (WWFMMP) open houses, held Oct 17 - 18, 2002, at which concerns about water quality were raised in connection with the 'Learn to Sail' programs which operate in areas such as Ashbridges Bay. As this recreational use often results in full body contact with the water, the public requested that the City make provisions in the WWFMMP to provide Ashbridges Bay and other boating areas with the same designation and protection as outlined for beaches.
Further to this, Councillor Sandra Bussin identified that a report from the Commissioner of Works & Emergency Services was received at a November 6, 2002 City Council meeting which outlined adjustments to 25 Year Implementation Plan for the WWFMMP. These adjustments included an additional allocation of $12 million in funding between 2008 and 2012 to make provisions for additional storage and treatment of stormwater discharging into Ashbridges Bay/Coatsworth Cut.
Following discussion of the WWFMMP there was general concurrence amongst those in attendance at TRCA's open house that further study may be required to assess the potential impact of the proposed breakwater on water quality in Ashbridges Bay. Of particular concern was the impact that the breakwater may have on the retention of stormwater which is discharged into north end of Ashbridges Bay. TRCA committed to further exploration of this issue and suggested the need to investigate the potential water quality improvements that the implementation of the WWFMMP would help to achieve for this area of the waterfront. Shortly after the public open house in November, TRCA initiated discussions with City staff and consultants responsible for the water quality modeling conducted in support of the WWFMMP. On March 19, 2003 an agreement was struck to model all of the design alternatives (1 through 5) that were explored through the Class EA process and to explore the impact of the preferred design in both of the proposed construction phases.
The water quality study took place from early spring to mid-summer of 2003. The same numerical model used in the development of the WWFMMP was utilized to simulate the existing water quality conditions. This model is considered state-of-the-art, creating a three-dimensional representation of the study area. The data utilized to undertake this modeling was again consistent with that used for the WWFMMP, including daily bacteria data.
The results of this modeling indicated that based on the existing conditions the creation of the proposed breakwater would have major impacts on water quality. Currently bacteria concentrations in Ashbridges Bay/Coatsworth Cut fail to meet the Provincial Water Quality Objectives (PWQO) on average 45% of the 90 day recreational season. The model predicted that this amount would increase to an average of 60% as a result of the breakwater. The projected effect of the breakwater on water clarity and nutrient loading is also detrimental. Of particular concern would be the impact on water quality in the mouth of Coatsworth Cut and in the area of the Ashbridges Bay Yacht Club. For example water quality conditions in the mouth of Coatsworth Cut would not meet the PWQO's for E. coli 73% of the 90 day season as compared to the current 41%. Whereas the amount of time the PWQO would not be met in the area of the yacht club would be more than doubled to account for 20% of the season. Water clarity would also be severely hampered in these areas. The yacht club in particular would see the greatest change in water clarity. Currently water clarity is only hampered for about 1% of the season. This percentage could increase to encompass about 80% of the recreational boating season. Nutrient loadings in the boat basin would also increase, which would be expected to cause an increase in attached algae growth. TRCA also had the consultant model the impact of the proposed breakwater based on the conditions proposed by the City of Toronto through the implementation of the recommendations outlined in the 25 Year Implementation Plan for the WWFMMP. Under these proposed conditions TRCA's preferred design would have much less impact on water quality. Based on the City's WWFMMP water quality targets for the area, the model predicted that the breakwater would have minimal to nonexistent impacts. In some instances the breakwater would actually marginally improve the City's targets for water quality.
On November 6, 2003 TRCA met with City of Toronto Works Department staff to discuss the project as it relates to the City's Class EA for the implementation of the WWFMMP recommendations. City staff identified that the Request for Proposals to initiate the Class EA process for the remediation of the outfalls at the north end of Ashbridges Bay would be developed and released in 2004. This would represent the first Class EA targeted under the 25 Year Plan for the WWFMMP. The recommendation outlined in the WWFMMP 25 Year Plan for Ashbridges Bay is a treatment wetland although other options will be explored through the City's Class EA process.
TRCA has identified our commitment to working with the City of Toronto to resolve any potential project conflicts, address the cumulative effects and ensure that our projects are well integrated. TRCA has also committed to collecting additional data related to fisheries, benthic invertebrate and aquatic plant production in Ashbridges Bay to assist with the City's Class EA process.
At a subsequent meeting of TRCA and City staff held on April 23, 2004, further discussions took place related to the existing and proposed projects within the Ashbridges Bay area. Other projects which could potentially affect the TRCA's work include the construction of a new outfall for the City of Toronto's Ashbridges Bay Treatment Plant and development of a Precinct Plan for Lake Ontario Park by the Toronto Waterfront Revitalization Corporation (TWRC). The Environmental Assessment for the new outfall is currently underway with completion anticipated to take place in early 2005. City staff expects that the construction of the new outfall will commence in late 2008 or early 2009. TWRC will initiate the planning process that will result in the development of a Precinct Plan for Lake Ontario Park this fall, encompassing the waterfront area from Cherry Beach to the Eastern Beaches, including Tommy Thompson Park.
After considering the potential impacts of the proposed breakwater on water quality and with knowledge of the many other planning initiatives that are underway or planned to commence this fall within the project study area, TRCA has decided to suspend the Ashbridges Bay/Coatsworth Cut Erosion Control Class EA. TRCA's Class EA process will not be resumed until the City of Toronto has developed its own plan as related to the recommendations outlined in the WWFMMP 25 Year Implementation Plan and can provide new water quality data.
TRCA will also continue to work with our partners to explore potential opportunities to remediate the existing navigation hazards through the other initiatives which are planned or underway within this area. Although a long-term solution to protecting the navigation of Ashbridges Bay/Coatsworth Cut has been delayed, TRCA remains committed to protecting the navigability of Coatsworth Cut. In 2003, 9,000 m3 of sand was dredged from Coatsworth Cut to ensure safe navigation. TRCA budgeted to continue our dredging operations in 2004. It is expected that 3,500 m3 of sand will be dredged from the mouth of the navigation channel this year as part of our fall work schedule.
For more information, please contact:
Moranne Burnet, Project Planning Coordinator at 416-392-9690 or mburnet@trca.on.ca
Laura Stephenson, Waterfront - Special Projects at 416-661-6600, ext. 5296 or lstephenson@trca.on.ca
NOTICE OF RECOMMENCEMENT August 2009:
August 2009NOTICE OF RECOMMENCEMENT
Toronto and Region Conservation's
Ashbridge's Bay/Coatsworth Cut
Erosion Control Class Environmental Assessment
In October of 2004, Toronto and Region Conservation notified the public and other interested stakeholders about TRCA's decision to suspend the Ashbridge's Bay/Coatsworth Cut Class Environmental Assessment (ABCC Class EA). The objective of the ABCC Class EA was to remediate navigation hazards resulting from the deposition of sediments in the harbour entrance to Ashbridge's Bay and Coatsworth Cut. TRCA's original decision to suspend the Class Environmental Assessment was based on concerns related to the potential for interference with City of Toronto's storm water management plan for the area, and Waterfront Toronto's plans for what would become the Lake Ontario Park (LOP) Master Plan (Fall 2008).
Since the Class EA process was suspended in 2004, TRCA has continued ongoing dredging of Coatsworth Cut to ensure safe navigation. TRCA has also been working cooperatively with the City of Toronto and Waterfront Toronto on a long-term vision for the Ashbridge's Bay area. LOP, as envisioned by Waterfront Toronto, is a waterfront park spanning from Cherry Beach in the west to the R.C. Harris Filtration Plant in the east. This large-scale Park, includes Ashbridge's Bay. The LOP Master Plan, proposes a treatment wetland in Coatsworth Cut and construction of a new landform at Ashbridge's Bay Park to facilitate relocation of the boat clubs currently located in Coatsworth Cut.
On May 13, 2009, Waterfront Toronto received Board approval to proceed with Phase 1 of LOP. In June 2009, TRCA decided to reinitiate the ABCC Class EA that was suspended in 2004. The objective of the Class EA remains as stated previously, "to identify a preferred solution that addresses navigation hazards due to localized sediment erosion and deposition". However, the alternatives will also be evaluated based on their ability to meet the long-term waterfront vision for this area as outlined in the LOP Master Plan.
The ABCC Class EA will proceed in accordance with the requirements of the Conservation Ontario Class Environmental Assessment for Remedial Flood and Erosion Control Projects (2001). Two Public Information Centres (PIC's) will be held during the study to provide information and allow for public comment. Notification of the PIC's will be advertised in the local newspaper and posted on TRCA's website: www.trca.on.ca.
This notice issued August 18, 2009.
For further information on this project, please contact:
Kenneth Dion, Senior Project Manager
Toronto and Region Conservation Authority
5 Shoreham Drive
Downsview, ON M3N 1S4
Phone: 416-661-6600 ext. 5230 Fax: 416-667-6278
Email: kdion@trca.on.ca
To find out more about the City of Toronto's Coatsworth Cut Sewershed Class Environmental Assessment,
please visit: City of Toronto.
