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Soft Engineering of Shorelines Based on a Binational Conference Sponsored by the Greater Detroit American Heritage River Initiative and Partners |
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Chapter 9 Enhancing Habitat Using Soft Engineering Techniques at the Northeastern Shoreline of Hamilton Harbour, Western Lake Ontario, Burlington, Ontario, Canada (John Hall) Introduction This harbor project is aimed at restructuring the fish community, from a community dominated by carp, to one more diverse and dominated by top order predators. The project is also aimed at providing rare colonial nesting birds with a safe, clean, and permanent habitat. This condition is more in keeping with improved water quality and closer to the harbor's previous relationship with Lake Ontario. Project Description The project included the creation of three islands,
isolated from the shore, to protect nesting birds from predators (Figure
29). Beaches and headlands along the shore provide vegetation and habitat
for wading birds. The islands and a chain of underwater shoals create
a quiet lagoon, resulting in aquatic plant growth, which is a requesite
habitat for fish spawning and nursery. Mudflats, exposed in the fall,
attract migratory birds. Construction began in 1993 and was completed
in 1995.
The shoreline restoration components include a beach,
headlands, wetland, and upland areas. The shoreline extends approximately
400 m and contains two headlands anchoring three beaches. An upland complex
of woodland and meadow is planted between the beach and adjacent highway.
A trail follows the length of the shoreline, terminating in a natural
lookout. At the south end of the project site is a launch ramp for windsurfers.
The upland portion of the shoreline contains a woodland, demonstrating natural succession of plant communities. Some oaks and Carolinian woodland species are included, since these species are native to the area and were recorded as previously growing on the beach. Islands The South Island, closest to the Burlington Ship Canal,
is planted with shrubs and small trees, creating habitat for black-crowned
night herons. Its windward side is constructed of armorstone and an underwater
reef extending approximately 4 m. The cobble slope of the reef is similar
to habitat used by spawning lake trout and whitefish. The lee side of
the island contains a wetland flooded during high water levels and exposed
during low levels. Fish habitat structures are integrated into the shoreline
of the island. The Center Island has shrubs and small trees vegetating
the south half of the island, while sand and pebbles cover the north half.
At the island's center, cormorant nesting platforms are constructed on
wooden poles with a 5 m buffer from the vegetated south half of the island.
A raised knoll at the north end of the island is covered with substrate
suitable for common terns. A fish spawning reef, approximately 4 m wide,
extends the length of the windward side of the island, while a small natural
beach is constructed on the lee. Drift material accumulates on the beach.
Fish habitat structures are integrated into the shoreline. The North Island is covered with a sand, pebble, and cobble surface. The surface also has randomly placed driftwood logs and other structures. Nesting knolls were constructed for Caspian and common terns. A reef extends from the windward side of the island. The lee shoreline contains a mudflat, which emerges during the low water levels in the fall, making it available for migratory shorebirds. Fish habitat structures are also integrated into the shoreline. Shoals The three shoals are connected by 9 emergent shoals which provide spawning habitat for fish and shelter the adjacent shoreline. Every second shoal is submerged during the spring and early summer. Alternate shoals contain higher breakwater mounds, which are visible to boaters. In the fall, when water levels in Lake Ontario drop, the shoals are used by wading shorebirds. Regulatory Considerations Many permits were required under the following agencies:
Cost
Post Project Evaluation of Effectiveness This site has proven to be a major success for colonial
nesting birds and fish (Figure 30). The Canadian Wildlife Service identified
the following bird species using the islands in 1997: Caspian terns, common
terns, black-crowned night herons, ring billed gulls, and herring gulls.
With the reduction in wave action, the aquatic plant community has increased
from zero plants to at least 50% vegetated cover. The fish community has
responded to this improvement. Fish species using this area have increased
in diversity from 6 to 16 species after rehabilitation.
The proponents felt that the best thing this project did was to form a project advisory board of stakeholders once a concept for rehabilitation was developed. This group was a combination of individuals from local interest groups, the science community, and relevant agencies. This group worked through the detailed design and environmental assessment stages. Since these groups had been involved from the beginning of the design stage, permits/funding approvals were easier to obtain. Funding and Implementation Partners Bay Area Restoration Council (representing citizens,
interest groups, municipalities, industries, and landowners);
Contact Persons The Fish and Wildlife Habitat Restoration Project
Vic Cairns |
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Last updated:
July 9, 2008
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