1. Project Title: Ruwe Marsh Protection Project - Phase 1
2. Contact
Don Hector, Project Coordinator
Lisa Tulen, Project Facilitator
Ontario Ministry of Natural Resources
1023 Richmond St. West, Chatham, Ontario N7M 5J5
P.O. Box 1168 N7M 5L8
Tel. (519) 354-7340; Fax (519) 354-0313
3. Agencies Involved
Great Lakes Cleanup Fund
Landowner and Leasee
Ducks Unlimited
Canadian Wildlife Service
Essex Region Conservation Authority
University of Guelph
Local Girl Guide chapter
Ministry of Natural Resources
U.S. Biological Survey, Dr. Bruce Manny
Dean Construction
4. Restoration Goal
The Ministry of Natural Resources, through the Detroit River Remedial Action Plan, is proposing the repair of an existing finger dyke structure at the Ruwe marsh at the mouth of the Canard River within the Detroit River. This finger dyke is essential in maintaining the integrity of downstream wetlands and dykes protecting the Canard River marsh system. Wind, ice and wave action have caused erosion of the existing clay structure.
5. Project Type
Dyke repair and re-construction; this will involve transportation of armour stone to the site by barge and placement.
6. Background and Rationale
The Ruwe marsh is a privately owned Class 1 marsh located north of the Canard River access in the Detroit River and is part of a 580.26 hectare wetland complex. This marsh complex consists of two water impoundment cells and an open water marsh mostly within the Detroit River proper. To the north of the wetland cells a long "finger dyke" runs parallel to the wetland dyke. This finger dyke protrudes into the Detroit River approximately 1 125 m and eventually turns in a downstream direction. The finger dyke extends into the Detroit River and effectively trains and re-directs the flow from the Fighting Island Channel around the wetland cells and associated shallow water areas. The recognized significance of the Canard River Marsh ecosystem as staging areas for Canvasback and Redhead ducks, especially during fall migration, results from the finger dyke's diversion of suspended sediments from the marsh. The finger dyke effectively creates a significant amount of calm water area and associated aquatic vegetation. Decreased turbidity allows diverse, abundant aquatic vegetation with high value as food for wildlife. The functional values of the finger dyke sheltering the Ruwe marsh extend throughout the wetland system. The finger dyke and aquatic vegetation of the Ruwe marsh buffer the remainder of the wetlands and dykes from the brunt of riverine forces, shipping channel wash, and ice scour, as well as diverting sediments.
Expected date of implementation pending funding and further approvals: January 1995
7. Regulatory Considerations
All approvals received:
1. Environmental Assessment - Provincal Class EA Planning Procedure;
Federal Environmental Assessment Review Process, because we were using federal funds (Environment Canada's Great Lakes Cleanup Fund);
2. Fisheries Act - approval from Department of Fisheries and Oceans (December 21, 1994), project deemed mitigable, no compensation necessary;
3. Navigable Waters Protection Act - Approval from Canadian Coast Guard, September 8, 1994;
4. Flood and Fill Regulations -- received review comments November 10, 1994, from Essex Region Conservation Authority, requested work permit.
8. Criteria
The key objective of this project is the protection of the existing habitat in this important area of the Detroit River. The existing finger dyke at the north end of the area is under stress from wave action and currents and has eroded considerably. Without this finger dyke, the calm water area to the south of the dyke would be affected by river sediments and current. The finger dyke is essential to maintain the integrity of downstream wetlands and dykes protecting the Canard River marsh system. As the present dyke is composed of clay, further loss of structure and habitat will result if not protected. Side slopes of the dykes should be no greater than 2:1 with 3:1 being preferred. Clean, sediment-free armourstone obtained from the local quarry will be used to repair this dyke.
9. Project Design
Repair and re-construction of the finger dyke will ensure protection of the existing wetland and allow enhancement and maintenance of wetland vegetation through a decrease in current and erosion.
Final engineering designs have been prepared by Jeff Jilek at the London Zone MNR office and are available from the project facilitator.
10. Implementation
Material required for reconstruction of the finger dyke will be from the local Amherst quarry. Construction will be by a private contractor responsible for obtaining material from the quarry, transporting it to the river front, transporting by barge to the site and placement onto the dyke.
11. Degree of Environmental Intervention
This project will require large marine equipment for transportation and placement of material. As this dyke has existed for several years, impacts will be minimal. Material necessary for re-construction will be brought to the site by barge to ensure all existing trees and vegetation will remain intact.
12. Cost
Preliminary project costs for phase 1 of the project have been estimated by Greg Wild of Ducks Unlimited and Dean Construction to cost approximately $300 K. Construction will be tendered to a local marine construction company.
13. Biological Assessment
The Canard River has been chosen as a marsh bird monitoring station for the Area of Concern wide marsh bird monitoring survey program. Reptile and amphibian monitoring will be coordinated by Brian McHattie of the Great Lakes Cleanup Fund. The Ontario MNR has conducted electrofishing surveys of the area in 1992 and a seining program for fish inventory has recently been completed at the wetland in 1994. A specific monitoring program for this project is being developed as a deliverable for the Great Lakes Cleanup Fund proposal.
Recently, Jim Corrigan of the University of Guelph, Biological Control Research Associate, released Galerucella sp. beetles as a control for purple loosestrife infestations within the dyked marsh. Future monitoring of purple loosestrife and Galerucella sp. colonies will be coordinated by Jim Corrigan and the marsh manager.
14. Measures of Success
Re-construction of this finger dyke structure will protect approximately 366 ha of provincially significant class 1 wetland including the dyked cell and open water marsh with both provincial and national significance. Re-construction will also provide protection to the inner dyke which is also composed of clay and is eroding due to holes in the outer finger dyke.
Success Rating: 1
15. Key References
Ministry of Natural Resources. 1994. draft version, "Survey of Candidate Sites on the St. Clair and Detroit Rivers for Potential Habitat Rehabilitation/Enhancement".
Correct citation for this contribution:
Hector, D., and Tulen, L. 1995. Ruwe marsh protection project - phase 1, p. 154-157. 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.