Home > TWAHRS > Consultation
May 15, 2003
Black Creek Pioneer Village
Summary Meeting Notes
Overview of Aquatic Habitat Restoration Strategy Process
Doug Dodge provided an overview of the process that is being used to develop the strategy (showed a powerpoint presentation on CD and the draft strategy document that was provided to meeting participants). He noted that the redevelopment of the Toronto waterfront represents an untapped opportunity to restore some of the ecological integrity of aquatic habitats that has been lost over the past two centuries. The strategy will establish a framework for changes that will lead to a more self-sustaining aquatic ecosystem while recognizing human uses of the waterfront.
Doug invited participants to provide comments on the draft document and powerpoint presentations at any time (to Gord MacPherson at gmacpherson@trca.on.ca, phone 416-661-6600 ext. 5246 or fax 416-667-6277).
Physical Processes, Aquatic Communities & Habitat Restoration Techniques
Gord presented the foundations of the strategy represented by physical processes and the existing aquatic communities on the waterfront. He also introduced participants to a draft compendium of techniques that can be used to restore aquatic habitats.
Questions and discussion included the following points:
Question: have you noticed an increase in dabbling and diving ducks in response to the increases in Vallisneria and other submerged vegetation?
Answer: yes — both resident and migratory birds are increasing in numbers and diversity. For example, canvas-backed ducks have nested recently in Cell 1 in Tommy Thompson Park.
Question: the amount of material removed from the shoreline by stone-hooking is incredible! Where do you expect that we can obtain enough material to put back on the waterfront?
Answer: there are several potential sources, including waste materials from quarries, constructions wastes including brick and concrete rubble, and rocks removed from green-field construction sites.
Question: can you predict the appropriate water levels for establishing emergent vegetation?
Answer: we survey existing wetlands to determine the preferred elevations for specific species and then grade the new shoreline to those elevations. But we still need to develop better understanding of the effects of high and low water levels.
Question: what techniques have you used to create a wetland on a contaminated site in Cell 1 in Tommy Thompson Park?
Answer: we placed 0.5 metre of clean fill over the contaminated sediment. We have tested this method on the 2 hectare Triangle Pond that was built in the early 1970s in Tommy Thompson Park. The sediments were heavily contaminated including lead above the severe effect level. We have done bore-hole testing that confirms that the contaminants are contained below the cap.
Question: do you know the rooting depth of the vegetation?
Answer: mostly 10-15 cm.
Question: there's a lot of work to do to add habitat function to the hard shorewalls around the harbour. How successful has the Harbour Square Park project been?
Answer: it's working well, attracting a variety of birds and fish.
Question: how do you plan to test performance of future restoration projects? You are really undertaking field experiments. Will you have control sites? Are you focusing on quantitative performance standards or qualitative directions?
Answer: we are working with University of Waterloo and DFO to develop performance measures and methods.
Comment: Ken Minns is working on an index of biotic integrity that will measure the performance of re-created shorelines based on 12 metrics in three categories — productivity, diversity and trophic status. It is being used in Hamilton Harbour and we are finding it to be both useful and reproducible.
Break-out Discussions
Participants divided into six groups — two each on open coast habitats, sheltered embayments, and estuaries/wetlands. They were asked to be creative and "think outside the box". As a result, some of the suggestions do not reflect factors such as regulatory requirements and land or waterlot ownership.
The groups discussed the following case studies:
- Open coast – Port Union; Fishleigh
- Sheltered embayments – Ashbridges Bay; Outer Harbour
- Estuaries/wetlands – Lower Don River; Humber River; Mimico Creek
The detailed notes from each group are below.
Plenary Reports and Discussion
Recurring Themes
- Specific objectives and themes should be developed for each case study, including aquatic habitat, terrestrial links, physical processes, water/sediment quality, and human uses.
- Restoration projects should be designed to allow for the ability to manage specific sub-areas (eg for carp control) and avoid re-creating existing problems.
- General acceptance of the proposed habitat restoration techniques.
- New habitat opportunities should be sought as well as retrofit opportunities.
- Recognize that this is an experimental management approach, providing opportunities to "learn-by-doing". Criteria should be developed to monitor success and to enable changes in management if necessary to respond to the results.
- Consider the long-term, big picture.
Constraints
Frequently-mentioned constraints included:
- Contaminants from outfalls (eg at Ashbridges Bay)
- Contaminated sediments (eg mouth of Don River)
- Ongoing sediment deposition and dredging requirements in mouth of Don River
- Transportation and land use constraints at mouth of Don River
- Flood control requirements at mouth of Don River
- Ice movement and scouring in estuaries
- Uncertainty about proposed energy generation projects and their potential impacts
- Dynamic conditions of the open coast
Design Concepts for Wetlands/Estuaries and Embayments
Some recurring ideas included:
- Small islands in the Outer Harbour
- Off-line ponds
- Modify existing water depths to encourage emergent vegetation
- Soften shorelines
- Increase sheltered waters
- Improve circulation
- Braided river in estuaries
- and estuary hooks
- Off-shore shoals
- Carp barriers
- Goose control
Design Concepts for Open Coast
An over-arching theme was to recognize the natural coldwater fishery and dynamic conditions of the open coast. It was suggested that modest shoreline enhancements could be made including:
- Surcharge with rocky materials
- Underwater reefs and shoals
- Repair boulder pavement
- Shoreline hooks
- Soften shorelines
- Woody debris on cobble beaches
- Incorporate habitat opportunities into shoreline erosion protection approaches
"Big Picture" Ideas
Discussion about the "big picture" re-affirmed the guiding principles of the aquatic habitat restoration strategy, with participants suggesting:
- We can make an analogy with human habitats in that we are trying to create a framework for diversity of aquatic life.
- Recognize and incorporate navigation requirements.
- Understand coastal processes including overall sediment transport (from watersheds as well as along-shore), ongoing erosion and shoreline replenishment.
- Avoid moving a problem (eg carp) from one area to another).
- Recognize that "valued ecosystem components" (eg desired fish species) vary from one stakeholder to another.
- Don't improve one valued ecosystem component at the expense of another.
- Define the problem and be specific about objectives for specific species of fish.
- Remove upstream barriers.
- Connect to terrestrial habitats.
- Recognize uncertainties for example invading species.
- Waterfront redevelopment process is iterative and will provide ongoing opportunities to ensure that projects incorporate aquatic habitat.
- Other case studies could include the proposed "deflector arms" at the mouths of the Humber River and Etobicoke Creek; recreational boating and international competition opportunities.
- Imagine 2050 — what will the waterfront look like then?
- Creating a more self-sustaining ecosystem will make it more capable of adapting to changing circumstances.
- Strategy should be both reactive (restore existing places) and proactive (set priorities for new work)
- Focus on building landscapes, not only on requirements of specific species.
Next Steps
Doug Dodge summarized the next steps, including:
- Participants will receive a summary of the workshop.
- Participants will be invited to a Public Forum planned for June 10th, 2003.
- The strategy will be presented to the TRCA Board in September.
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