How To Plan A Flood Protection Project In Toronto

Transcription

1 Lower Don River West Remedial Flood Protection Project Public Open House and Meeting #3 Meeting Notes September 21,

2 PUBLIC OPEN HOUSE AND MEETING #3 1.0 Public Open House Tuesday, September 21, 2004 Metro Hall Room 308/ John Street, Toronto 6:30 9:30 p.m. SUMMARY NOTES The Open House opened at 6:30 p.m. Members of the public viewed display panels showing different aspects of the Lower Don River West Remedial Flood Protection Project (LDRW). Toronto and Region Conservation (TRCA), and members of the consulting team from Dillon Consulting Limited, Acres International and ENVision the Hough Group were on hand to answer questions during the Open House. All participants received the following information: Public Open House & Meeting No. 3: Summary of EA Process & Functional Design - Workbook Lower Don River West News newsletter, Edition Welcome and Introductions Adele Freeman (Acting Director of Watershed Management, TRCA) opened the meeting at 7:35 p.m. She thanked the members of the Community Liaison Committee for their ongoing advice and hard work, and Joe Puopolo (Dillon Consulting Limited) and the entire consulting team for their leadership and the design being presented. All those involved have tried to keep to the October 15, 2004 deadline the anniversary of Hurricane Hazel. The Lower Don River area has been a priority for many years. It is intended that there will be a draft document by mid-october. Later in the fall, it is likely that there will be a consultation initiative to discuss all activities related to the Precinct Planning initiative. All stakeholder names will be provided to the Toronto Waterfront Revitalization Corporation (TWRC) so information/notification can be circulated as it becomes available.. Appendix A contains a list of all those who signed in at the meeting. Appendix B contains a list of project team members who were at the meeting. 2

3 3.0 Project Presentation 3.1 Study Overview Joe Puopolo started the presentation by giving an overview of the study. He explained that under a storm event the size of Hurricane Hazel, the anticipated floodplain surrounding the lower Don River and Keating Channel would extend to the west, east and south of the river. This floodplain has been broken into three Spill Zones. This study covers Spill Zone 3 (210 hectares), which extends to the west of the Lower Don River and south of the CNR embankment along Toronto s central waterfront. The purpose of the study is to protect Spill Zone 3 should severe weather such as Hurricane Hazel ever occur again. This study is being conducted as a Conservation Authority Class EA (Class EA) at the provincial level. At the federal level, this project falls under the Canadian Environmental Assessment Act (CEAA). These pieces of legislation require public consultation and an evaluation of a range of alternatives. The West Don Lands Precinct Plan and the Master Servicing Class EA for the West Don Lands are also being undertaken by the TWRC. Two previous Public Information Centres have been held in January and April, Project-related information is posted on the TRCA website for anyone who is interested. 3.2 Study Process Joe Puopolo described the planning process followed in this study. First, a long list of 13 alternatives was developed that either alone or in combination could potentially provide the flood protection that is being sought in Spill Zone 3. Next, a screening process was carried out to determine if the alternatives satisfied each of the following three mandatory criteria: - Does the alternative achieve flood protection to the Regulatory Flood Level for the Lower Don River West Lands/Spill Zone 3? - Does the alternative comply with current provincial floodplain policies, including the technical requirements associated with a permanent solution? - Is the alternative technically feasible/proven? Once these screening criteria were applied, 8 of the 13 options were eliminated from further consideration. The remaining 5 alternatives met all screening criteria and were carried forward to a short list. These options were: A Flood Protection Landform (Berm) with East Dyke (Berm) and Culvert B Wedge with East Dyke (Berm) & Culvert C CNR Bridge & Channel Widening D Secondary Channel with Flood Protection Landform E River Dredging This information was presented at the second public information centre and is available on the TRCA website. 3

4 Six different disciplines (physical, biological, cultural, socio-economic, technical/engineering, cost) evaluated this short list to devise a ranking. In total, there were 39 criteria considered across the disciplines. Each alternative was considered in terms of its impact both during construction and throughout the lifespan. Option A emerged as the preferred alternative. This option is composed of five elements. 1. Flood Protection Landform 2. Flood Protection Works for the East Bank (interim and may be altered as part of naturalization of the mouth of the don project) 3. Culverts under CNR Embankment 4. Continued Dredging of Keating Channel (to ensure proper hydraulic capacity) 5. Modification to the Utility Bridge Many elements have been harmonized with the Precinct Planning efforts that are going on. A computer rendering of the flood protection landform was shown. The flood protection landform will only result in a slight rise/roll on the topography. There is one final piece of work being completed: to provide guidance to the Precinct Planners on the kind of plantings that can go on in the flood protection zone. Five vegetation zones have been identified. Zone 1 is the most restrictive zone, which covers the western bank of the Don River and the eastern (riverside) slope of the landform. The consultants recommend that no heavy trees be planted here, only herbaceous species and shrubbery. In Zone 2 (at the apex of the landform), it is recommended that any plantings that may prevent future alterations to the landform be restricted (for example large trees may inhibit the expansion of the peak of the landform to address potential climate change issues). There are fewer restrictions as one moves west through Zones 3, 4 and 5. In Zone 5, there are very few restrictions on the types of planting. 3.3 Next steps: The project team would like to get feedback by October 6, 2004 on the materials presented at this meeting. The handout contains a number of discussion questions that participants were encouraged to give feedback on. Draft Class EA and CEAA documents are to be completed in October In November, geotechnical/geoenvironmental fieldwork for the CNR Crossing will take place. In December, the Functional Design will be completed. 4.0 Questions Regarding the Presentation: After the presentation, stakeholders were invited to ask questions of the project team. 1. Can you expand on how the wetland to the south deals with the flood problems in Zones 1 and 2? 4

5 Joe Puopolo explained that a separate project - the Don Mouth Naturalization and Port Lands Flood Protection Project - will address Spill Zones 1 and 2. This separate project will provide flood protection for Spill Zones 1 and 2 (to the south and east of the Don River), and will also explore potential naturalization options for the mouth of the Don River and the Don Narrows. Although the proposed flood protection works for the Lower Don River West Remedial Flood Protection Project do not address the issue of flooding through Spill Zones 1 and 2, a key criterion for the evaluation of the preferred alternative was that it would not aggravate flooding in these Spill Zones. In essence, the floodwaters that would be redirected by the landform will be conveyed south - through the CN Rail berm - by the proposed culverts. Adele Freeman added that the Don Mouth Naturalization and Port Lands Flood Protection Project is moving forward at this time. The consulting team, led by Gartner Lee Limited will be engaged in the upcoming months as the study moves forward. Public consultation will be an integral part of this project. 2. Have you done any hydraulic modeling? Joe Puopolo stated that hydraulic modeling has been completed to evaluate all flood protection options, to refine the Functional Design and to determine the size of the culverts. The computer model has been calibrated to a physical model. A two-dimensional modeling system was used to address the issues of water moving down the river and spilling over the banks on either side (water movement to the south, as well as east-west). This was the model carried forward and used to look at the long list of options for the project. A one-dimensional model is being used to evaluate the functional design and the configuration of the culverts under the CN Rail tracks. The water will be somewhat confined by the flood protection landform (no movement to the west, only south), and so a one-dimensional assessment should suffice for this stage of evaluation. 3. If you replace the concrete with wire mesh on the Utility Bridge, who will manage the debris once the water levels recede? Adele Freemen explained that some planning still needs to be done to address this. Sometimes the TRCA has maintenance agreements with other agencies to take care of these needs. There is a whole series of operational issues like this that need to be investigated and tied in to the final design. 4. What are the cost estimates for the design, landform, and remediation work? 5

6 Joe Puopolo explained that the Ontario Realty Corporation (ORC) and the TWRC are developing a strategy for the remediation work. This strategy will consider the bigger picture. In terms of individual elements of this project, the east bank will cost $250,000; the culverts and landform are estimated to cost approximately $14 million, however these figures still need to be refined. The landform itself is anticipated to cost roughly $2 million. Adele Freeman added that the TWRC still needs to develop a contribution agreement from all levels of government. Currently, this project isn t at this stage yet. It is at the point of finalizing the design. 5. What did the modeling show for the necessary flood protection for the east side? Joe Puopolo explained that the criteria used for this project was that flooding on the east side could not be worsened (i.e. a zero sum gain). Spill Zones 1 and 2 don t get altered by this project; they are taken care of by the next project Adele Freeman added that the TWRC now has the money for that additional study to go ahead. An individual Environmental Assessment (EA) will go ahead to deal with the other two Spill Zones. The large landform proposed by this project is permanent and will stay, independent of the outcome of the other study. 6. I understand that there is funding to do the studies, but no funding to actually do the implementation work. Will this project get part of the $330 million announced this summer? Adele Freeman explained that once the Functional Design has been refined and the EA reports completed, detailed cost estimates will be provided to TWRC. They may incorporate this into the West Don Lands Precinct Planning envelope. This will then be taken forward to the three levels of government for funding approval before the implementation of the final design. 7. What would naturalization look like for the mouth of the Don? Adele Freeman stated that TRCA has done some research on this. Additionally, during the consultant selection process for the Don Mouth Naturalization and Port Lands Flood Protection Project, consultant teams were asked to provide their own visions for the mouth of the Don. A naturalized mouth of the Don River may include: the presence of enhanced habitat for pike and walleye populations; an estuary; reconfiguration of some of the roads; The area may be lowered and blend with the New Commissioner s Park; and There may be some changes to the Keating Channel. 6

7 8. I am trying to envision the tunnel. How will this be made friendly for the public? Is there a budget item for public art projects? On the Gardiner East project, the public art budget helped to make the project more acceptable/ sustainable/ friendly. This budget line should be added now, so there is recognition that this is important. Adele Freeman explained that ENVision the Hough Group has been asked to provide some sketches to show what the entrances of the tunnel will look like. It is acknowledged that this is an important consideration. The TRCA also plans to work with the City of Toronto Parks Department. Some type of meshing could be incorporated into the design to narrow it down a bit. Lighting will be key. 9. What is the timing for the culvert? How long will it take to complete? Joe Puopolo stated that the planning for the culverts is currently underway. Ideally, the construction of the culverts will start in the spring of 2005 and take 2 or 3 months to complete. It will be necessary to coordinate the construction of the culverts with the schedules of CN Rail and GO Transit. The timing of the construction will be constrained by the need to maintain traffic along the rail lines most likely limiting work time to nights and long weekends. 10. How much fill will be needed for the landform? Joe Puopolo responded that although the landform covers a wide area, not much height will be added over the current grading due to its gentle slope. As a very rough estimate, the amount of fill needed is likely in the range of 200,000 cubic metres. 11. What is the average flow (cubic metres per second) on the Don? How about through the culverts? Don Haley responded that the average flow during regular flow conditions on the Don River is approximately 3 cubic metres per second. During normal spring flood conditions (when the banks are full), the flow is cubic metres per second. During Hurricane Hazel, the flow was 1600 cubic metres per second. Water is moving 6 metres per second. The capacity of the culvert will be approximately 1550 cubic metres per second. This will provide conveyance under the CN Rail berm for all of the floodwaters that have been redirected by the flood protection landform. The additional flow of 50 cubic metres per second (the regulatory flow to the east - into Spill Zones 1 and 2) will be addressed by the flood protection works associated with the Don Mouth Naturalization and Port Lands Flood Protection Project. 12. Spill Zones don t represent the original floodplains, aren t they man made? 7

8 Don Haley responded that the entire Toronto waterfront is man-made. The original Ashbridges Bay marsh was filled in at the turn of the century, and much of the shoreline has experienced infilling as well. This is evidenced by the lack of valley walls in the lower Don, where the gentle topography exacerbates the flooding by allowing the water to spread out to the east and west. 13. Why isn t vegetation on the landform part of this design? Why were the option of upstream storage and other forms of remediation upstream discarded? Adele Freeman explained that the naturalization of the Don River is a key priority for TRCA. This study focuses strictly on providing flood protection for Spill Zone 3. The recommended vegetation zones developed by the consultant team relate to the hydraulic requirements of the floodplain underneath the landform. The Task Force to Bring Back the Don asked TWRC whether the naturalization of the Don Narrows could be considered as part of this project. The design is constrained by the Don Valley Parkway and the CN Rail lines, and there is not much that can be done with this area, as most alternatives are too costly. Naturalization alternatives for this stretch will be explored as part of the Don Mouth Naturalization and Port Lands Flood Protection Project, and have not been included in this Class EA. Joe Puopolo added that upstream storage was explained at a previous open house. Based on the volume of water associated with the regional flood, upstream storage sites would not provide adequate storage. It has been assessed that 25 to 30 major structures the size of G. Ross Lord Dam would be necessary to eliminate the flood risk for the river. Millions of cubic metres of storage would be necessary, and this cannot be achieved without a serious negative impact on the entire valley system. Achieving such flow reductions would not be technically feasible, and using upstream storage in a smaller capacity to simply mitigate flooding downstream would not make a significant difference on the high volume of flow. Adele Freeman added that the impact that upstream storage sites would have on the flow of water during an event the size of Hurricane Hazel would be negligible. Given this fact however, it should be noted that although TRCA will not be including upstream storage as part of this particular project, the Authority still actively pursues all opportunities to enhance the stormwater management capacity of the watershed outside of this flood protection work. TRCA will be working with the City of Toronto to implement the Wet Weather Flow Management Master Plan (WWFMMP) to achieve enhancements in quality/quantity storage on the Don River wherever possible. Unfortunately this is very difficult in such a built up, urban area. 14. What is the technical reason why you don t want vegetation in Zone 1? 8

9 Joe Puopolo explained that since Vegetation Zone 1 is the floodplain of the river, vegetation must be limited by the hydraulic requirements of the area. Larger vegetation would provide a rougher flow surface along the floodplain, which would slow down the flow of water, effectively backing up the river. In the case of a regulatory flood, the intent is to convey this high volume of water past the landform and through the culverts too much roughage would inhibit the effectiveness of the flood protection works, and cause problems upstream. For this reason, vegetation within zone 1 must be limited to herbaceous plants and shrubbery. In addition, large trees would present a risk to the function of the culverts and the stability of the landform. If such trees were dislodged during a flood event, they could get caught in the culverts, seriously impacting their ability to convey floodwater under the CN Rail berm. If trees with deep roots were uprooted by the force of the flood, they would expose the soil of the landform to intense erosive forces, which in turn could compromise the integrity of the structure. 15. This isn t really a floodplain. Who will manage this? There should be some consideration to planting some trees on the top of the landform. There is a mandatory 40 metre setback from the foot of the landform to allow sufficient hydraulic capacity, and this will act as the floodplain. There are operational considerations that still need to be worked out with the Precinct Plans to determine the management of the area after construction. 16. What is the rationale for stability of the landform? The landform is essentially fill with some grass and shrubbery on it. Is there some rubble material needed at the base of the construction? Don Haley explained that the flow velocity during a flood the size of Hurricane Hazel would drop from 6 metres per second in the centre of the river to 2 metres per second at the edges the landform will contain and redirect the floodwaters, but will not meet with the brunt of the force flowing downriver. These factors will be considered during the design phase. Joe Puopolo added that there are compaction specifications that will be met to ensure a stable and permanent landform. Rubble material is not needed. 17. In heavy rains, we hear about Combined Sewer Overflows (CSOs). To what extent do storm sewers emptying into the Don contribute to the flows? Joe Puopolo explained that the four CSOs that currently empty into the lower Don River will be eliminated through the Master Servicing Plan of the West Don Lands. They will be moved and empty to Cherry Street. 9

10 Adele Freeman added that there are many more CSOs upstream that have a greater impact on the Don River. When the WWFMMP is implemented, overflows should be reduced from overflows per year to 3 overflows per year. 18. It is the City s policy to increase tree cover, where possible. Should this be sent back to design so that they could consider flipping the current design to increase cover (i.e. put the playing field adjacent to the river)? Adele Freeman/Ken Dion responded that the park is to be an integrated use park. The vegetation restrictions on the landform were developed in January 2004, and the Precinct Planning group was aware of this when they developed their design. Joe Puopolo added that if there is grading above the 82 metre elevation mark (the minimum elevation of the landform), there is the opportunity to add more plantings. Most restrictions on vegetation are only for the first 60 metres of the landform there are few limitations on plantings west of the top of the landform. It is noted that the concepts presented tonight are open for comment, and feedback is welcomed on the recommended vegetation zones. 10

11 5.0 Closing Adele Freeman thanked participants for their questions and input and encouraged people to mail in any additional comments they might have. Comments should be forwarded to: Alex Blasko Don Watershed Technical Clerk Toronto and Region Conservation 5 Shoreham Drive Downsview, ON M3N 1S4 ablasko@trca.on.ca Copies of the panels from the open house and the meeting summary from this evening will be posted on the TRCA website at: Comments are appreciated and taken seriously. The TRCA and the consulting team will be working towards incorporating stakeholder ideas into the final document. The meeting closed at 9:07 p.m. Participants were invited to remain and view the display boards and/or talk to project team members. Prepared by: Tracey Ehl, Principal (905) tracey@ehlharrison.com 11

12 Lower Don River West Remedial Flood Protection Project Public Open House and Meeting #3 Appendix A List of Participants September 21,

13 Appendix A: List of Participants Name Dennis Bartels Bryan Bertie Laurie Bruce Margaret Buchinger Carmela Canzonieri Peter Cely Angus Cranston John Crawford Tija Dirks Michael Giulioni Chris Holz Karine Jaovich Greg Lintern John MacMillan Peter Pfingst Richard Reinert Bill Snodgrass Kelly Snow David White John Wilson Paul Young Affiliation Citizen Task Force to Bring Back the Don Consultant to HRSDC Don Watershed Regeneration Council Don Watershed Regeneration Council Grace City of Toronto Resident Task Force to Bring Back the Don Citizen ORC/The Fettey Group Foodshare Field to Table City of Toronto Planning Citizen Self/Community Air and Vision (GWNA Newsletter) City of Toronto Water and Wastewater Services City Planning Resident Task Force to Bring Back the Don SRCHC 13

14 Lower Don River West Remedial Flood Protection Project Public Open House and Meeting #3 Appendix B List of Project Team Members September 21,

15 Appendix B: Project Team members Adele Freeman Don Haley Ken Dion Alex Blasko AmyThurston Joe Puopolo Don McKinnon Jennifer Harris Carl Bodimeade Caroline Marshall Tracey Ehl TRCA Project Manager TRCA Senior Hydrologist TRCA Watershed Resources Senior Planner TRCA Don Watershed Technical Clerk TRCA Don Watershed Resources Planner Dillon Consulting Limited Project Lead Dillon Consulting Limited Dillon Consulting Limited ACRES International Consultant Lead on Soil and Groundwater Contaminants ENVision the Hough Group Eh Harrison Consulting Inc. (Meeting Notes) 15