mats were filled by hand. Rock sizes used for gabion fill ranged from 80 to 140 mm. Each mat is 230 mm thick, and was divided by additional gabion meshing into cells 1000 mm by 3000 mm.
1. Project Title: McVicar Creek Rehabilitation
2. Contact
Doug Geiling
Great Lakes Laboratory for Fisheries and Aquatic Sciences, Department of Fisheries and Oceans, 1 Canal Drive, Sault Ste. Marie, Ontario P6A 6W4
Tel.: (705) 942-2848; FAX: (705) 941-3025; E-mail: Geiling@ssmare.ssm.dfo.ca
3. Agencies Involved
North Shore of Lake Superior Remedial Action Plans*, 1194 Dawson Road, Thunder Bay, Ontario P7B 5E3
(* Includes Environment Canada, Great Lakes Cleanup Fund, Ontario Ministries of Natural Resources and Environment and Energy)
Department of Fisheries and Oceans, Great Lakes Laboratory for Fisheries and Aquatic Sciences, 1 Canal Drive, Sault Ste. Marie, Ontario P6A 6W4
4. Restoration Goal
Prevent erosion of the modified creek banks and improve creek bed substrate quality.
5. Project Type
Creek bank stabilization and replacement of a fine sediment laden rocky creek bed.
6. Background and Rationale
In 1985, a road overpass was constructed beside the lower 120 m of McVicar Creek. Sand and debris eroded from embankments, slumped into the creek, settled on the creek bottom, and accreted in the estuary. As a result, interstices in the creek bed were filled and passage of anadromous fish to the upper reaches of the creek was impeded.
McVicar Creek has supported spring spawning runs of at least rainbow trout and smelt. Walleye have also been reported in the lower creek in May, but whether they have used the creek for spawning is uncertain.
Bank stabilization works and replacement of the creek bed were
initiated in December 1991. The portion of work not completed
by the end of March 1992 was resumed in October 1992. Bank
stabilization, replacement of the creek bed, and terracing of
the lower portion of the road embankment were completed by December
1992. The road embankment was seeded with grasses, and 600 mixed
conifers indigenous to the area were planted in the summer of
1993. To ensure the stability of soils on the embankment, further
plantings of up to 1700 mixed shrubs, deciduous and coniferous
trees (all indigenous to the area) will be completed in 1994.
7. Regulatory Considerations
a) Completion of an Ontario Ministry of Natural Resources Class Environmental Assessment for Water Related Excavation, Dredging, and Fill Activities.
b) File a Government of Canada Environmental Assessment Review
Process Screening
Decision Document.
c) Obtain an Ontario Ministry of Natural Resources Work Permit.
d) Ensure rock fill added to the estuary conforms with the Ontario Ministry of Environment and Energy Lake Filling Guidelines.
8. Criteria
Stabilization of the road overpass embankment and creek banks are fundamental concerns. Secondary issues include the removal of any impediment to upstream migration by fish and recreating spawning habitat in the lower creek. Vegetation and landscaping works were used to combat erosion on the road overpass embankment rather than inclusion of hard structures. Creek bank stabilization structures should not preclude the redevelopment of riparian vegetation.
9. Project Design
Trees were planted on the upper portion of the road overpass embankment to begin stabilization of the soil. Two terraces were designed for the lower portion of the embankment such that materials which eroded during construction and landscaping were less likely to reach the creek. The upper terrace served initially as road access to the site; ultimately, both terraces can be used as walkways along the lower creek.
Gabion mats were dug into the creek banks to prevent slumping of the banks into the creek. The mats will gradually fill in with organic matter and materials transported by surface runoff, allowing for gradual revegetation of the shoreline. The lakeward end of the terraced area was protected from wave action by the placement of armour stone (Figure 1).
Rocky substrate removed from the creek bed by excavation was replaced with a clean assemblage of rock suitable as spawning habitat for rainbow trout, smelt, and walleye. These new materials were placed to allow for unimpeded passage of fish to the upper reaches of the creek, but were not arranged to not create a channelized ditch of uniform depth. The width of the creek was restored to approximate pre-overpass conditions.
10. Implementation
A strip of land to the south of and parallel to the lower creek was leveled to provide access to the site. This strip would later become the upper terrace (Figure 1). Excavating equipment worked its way from the roadway bridge downstream when shaping the banks for gabion mat placement and creation of the lower terrace.
The southern (embankment) creek bank was shaped at a 2:1 horizontal:vertical slope. The slope extended 5 m up from the creek bed. A strip not less than 2.4 m wide was leveled above this slope to form the lower terrace. The slope of the north shore was not altered, but the ground was smoothed to facilitate the placement of gabion mats. From the roadway bridge to 15 m downstream, the northern shore was smoothed from the creek bed to 7 m up the slope, while the rest of the shore was smoothed 8 m wide.
The excavated slopes were lined with filter cloth prior to placement
of the gabion mats. The gabion mesh was laid in place and the
mats were filled by hand. Rock sizes used for gabion fill ranged
from 80 to 140 mm. Each mat is 230 mm thick, and was divided by
additional gabion meshing into cells 1000 mm by 3000 mm.
The creek bed was excavated wherever fine sediment loading was visually apparent. Excavated materials were trucked off site. Clean cobble (100-250 mm, 205 tonnes) and gravel (5-20 mm, 105 tonnes) were evenly spread among the excavated areas. Final shaping of the creek bed distributed the substrate into a mat averaging about 500 mm thick. This mat is 16 m wide at the roadway bridge narrowing to 5 m wide 26 m downstream. From 26 m downstream to 52 m, the creek bed narrows further to 3 m. The 3 m width is maintained to the mouth of the creek.
After the creek bed was complete, boulders (500-750 mm, 100 tonnes) were randomly placed in the creek along the entire length of the project. The boulders serve to both deflect the currents in the lower creek and to provide refugia.
Armour rock (600 mm minimum, 700 tonnes) was placed along the shoreline to the south of the creek mouth to protect the ends of the terraces and exposed embankment shoreline from wave action. The armour rock was placed back from the shoreline to allow for the redevelopment of a wetland area which existed prior to overpass construction.
The overpass embankment is largely composed of an assemblage of
sizes of inorganic granular fill. This material was first smoothed
and then covered with a 100 mm thick layer of topsoil
(3800 m2). The topsoil was in turn covered with biodegradable
straw erosion control mats. Volunteers planted 600 donated mixed
conifers through holes cut in the mats to help stabilize the soils.
Grasses were not planted as the topsoil was not sterilized and
contained the seeds of various plants.
Excavation of the creek and banks, gabion mat and new substrate placement, and terracing works were initiated in the period December 1991 to March 1992. All of these works were completed between October and December 1992. Landscaping of the embankment and tree planting were completed in the spring and fall of 1993. Augmentative plantings will occur in the summer of 1994 to ensure the stability of embankment soils.
11. Degree of Environmental Intervention
At one time or another, the entire project site was directly impacted by heavy construction equipment. The sparse vegetation on the overpass was largely removed during reshaping of the embankment. Remaining vegetation was covered by topsoil. No effort was made to save resident biota during excavation of the creek bed. However, winter excavation of the creek bed mitigated the effect on fish populations as few fish would be present and no species whose eggs incubate in the substrate over winter were known to use the lower reach of the creek for spawning. The benthic macroinvertebrate community would have been primarily affected.
12. Cost
Construction:
Labour and Materials $145 000
Engineering Design/Support $25 000
Contract Administration $20 000
On-Site Supervision $10 000
Landscaping $15 000
Subtotal, Construction $215 000
Assessment (estimated):
Field Crew (1 person week/year, 5 years) $3 600
Data Analysis & Reporting ($500/year) $2 500
Subtotal, Assessment $6 100
Total Estimated Project Cost $221,100
NOTES: To achieve efficiencies of scale, construction of this project was tendered in conjunction with another local project. Therefore the cost quoted is a best estimate. Also, all costs quoted above except landscaping were inflated by the necessity of changing construction contractors half way through the project.
13. Biological Assessment
Assessment of the McVicar Creek project will be qualitative. The creek mouth has been sampled with a beach seine in spring, summer, and fall each year since 1990. Seine sampling will continue at least until 1996. The use of the lower creek by spawning fish will be visually monitored in daylight in spring and fall. Night visual surveys using a high-powered hand-held spotlight will be added during May to monitor walleye and smelt use of the lower creek.
14. Measures of Success
Success will be estimated in terms of the fish community and the
physical environment. The
project will be deemed at least a partial success if:
1. the overpass embankment is stabilized and doesn't contribute
erosional materials to the
lower creek,
2. the substrate of the lower creek remains largely sediment free
and fish migration is not
impeded, and
3. the gabion mats become vegetated.
Complete success will be assumed if spawning by species in addition
to smelt occurs in the
lower creek.
Success Rating: 1
Final plantings to stabilize the overpass embankment have yet to occur, thus assessment of the physical component of this project is not yet possible. However, early results of fish community monitoring are encouraging. Smelt still use the lower creek for spawning in the spring. Also, chinook salmon have been observed to spawn in the lower creek in the fall of 1992 and 1993. Evidence of chinook spawning in the lower creek prior to rehabilitation is lacking.
15. Key References
None.
Correct citation for this contribution:
Geiling, D. 1995. McVicar Creek rehabilitation, p. 45-50. In J.R.M. Kelso and J.H. Hartig [editors]. Methods of modifying habitat to benefit the Great Lakes ecosystem. CISTI (Can. Inst. Sci. Tech. Inf.) Occas. Pap. No. 1.