Berlin, D; Wang, T; Woltman, M; Mylly, A; Sharp, R; Major, C; Cooper, G
The Esquimalt Graving Dock (EGD) is located on federal Crown-owned property in Esquimalt Harbour on Vancouver Island, British Columbia, and is managed by the federal custodian Public Works and Government Services Canada (PWGSC). The EGD facility has been operating for the repair and maintenance of military and civilian vessels since 1927, and it is the largest solid-bottom commercial dry dock on the West Coast of the Americas. Historical contamination includes a broad range of chemicals, such as metals, polychlorinated biphenyls (PCBs), tributyltin (TBT), and polycyclic aromatic hydrocarbons (PAHs). In support of objectives of the Federal Contaminated Sites Action Plan (FCSAP), as well as a potential governance change of the EGD facility, PWGSC developed a multi-phase remedial action plan for cleaning up contaminated sediments in and adjacent to the EGD waterlot. Phase 1A was completed in 2013 and included installation of a sheetpile perimeter wall around the existing timber jetty structures to prevent re-contamination of remediated sediments during subsequent phases of the project. Phase 1B was completed in March 2014 and included 144,000 cubic metres (m(3)) of remedial dredging and off-site upland disposal of contaminated sediments, placement of approximately 24,000 m(3) of in-water slope armour, and placement of residuals management cover (RMC) over approximately 74,000 square metres. This paper discusses the key challenges encountered during the Phase 1B remedial design, contracting, and construction, including development of the dredge design, residuals management approach, accommodating highly variable operational needs into the construction sequencing approach, developing contract documents to account for local contractor experience, and specific elements that presented a challenge during construction.