Fraser River and Meadow Avenue Remediation
Burnaby, British Columbia
Date of Execution: March 2002
Significant Project Features:
- Removal of existing wharf and obstructions prior to initiation of remedial action.
- Sediment removal conducted using Sevenson's innovative caisson dredging methodology.
- Perimeter installation of low permeability SEAL Wall System as well as traditional steel pile around the site.
- Stabilization of dredge spoils prior to offsite transportation and disposal.
- Installation and O+M of a temporary WWTP sized at 75 gpm to treat recovered groundwater.
- Restoration and capping of site included marsh area plantings.
Location of Project
The Meadow Avenue Remediation site is located along the North Arm of the Fraser River in Burnaby, British Columbia. The Fraser River is a busy route for shipping and transportation.
Description of Work
Sevenson was contracted to manage and execute the remedial action phase of this project. The first work task required the installation and operation of the temporary waste water treatment plant (WWTP). The treatment plant continuously treated recovered groundwater at a rate of 75 gpm to remove dissolved iron, metal hydroxides and PAHs. The final effluent was required to comply with the Greater Vancouver Regional District criteria for sanitary sewer discharge.
Prior to the construction of permanent sheet pile walls and the wharf, above and below water obstructions included three Marine Derricks and the old wharf were removed. The inshore wall, off-shore wall, and wharf wall used varying lengths of Sevenson's patented low permeability SEAL System Sheet Piling totaling 1,970 LF. In conjunction with construction, support systems and backfilling were required behind the inshore wall and wharf.
Dredging activities were performed in six cells using Sevenson's innovative caisson dredging method. Using a caisson, water was pumped from the caisson to the river prior to sediment removal. The sediment was removed using a piletop drill unit. Any remaining water in the caisson was solidified and the area backfilled with sand. The caisson was removed and mobilized to another location to continue sediment removal. Impacted sediment and materials were disposed off-site and the wastewater was treated at the temporary WWTP.
Sevenson constructed a cap over the site. The cap contained an 18 inch Aquablok layer, granular fill layer, riprap and marsh soil.
To complete remediation activities, miscellaneous marine and civil construction was required. This included installation of 1,000 timber densification piles; marker dolphins complete with cap plates and lugs for moorings; and log booms with chain connections. The site was restored with marsh plantings. In addition, two storm drains were installed as well as asphalt paving, and concrete along the Timber Wharf completed the restoration.
Health and Safety Overview:
- Unique Characteristics: Working in and around water; installation of caissons; compliance with Canadian health and safety requirements.
- Health and Safety Measures: Compliance with an approved HASP. Regular site inspections by British Columbia Worker Compensation Board.
- Health and Safety Staff: One (1) Health and Safety Officer
- How 40-Hour Training Was Implemented: Canadian law required training be completed locally. This included site specific, job task specific, and Canadian right to know.