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Implementation of Sediment Remediation in a Working Harbour - Lessons Learned in Esquimalt Harbour
Michael Bodman1, Kristen Ritchot2, Shauna Davis3, Derek Ormerod4
1Department of National Defence
2Public Services and Procurement Canada
3Defence Construction Canada
4Anchor QEA
The objective of this presentation is to share some of the lessons learned in undertaking remediation of 11 separate contaminated sediment sites in Esquimalt Harbour through eight distinct projects with a value of more than $155M.  
Abstract

Esquimalt Harbour, located at the south end of Vancouver Island, British Columbia, is the primary Pacific homeport for the Royal Canadian Navy (RCN). The majority of aquatic lands in the harbour are owned and managed by the Department of National Defence (DND). Addressing environmental risks associated with contaminated sediments in Esquimalt Harbour is a high priority for the RCN and DND based on the levels of contamination present and the potential for these sediments to result in human health and environmental risks. Since much of the sediment contamination present in Esquimalt Harbour is the result of historical activities and sources, the remediation and risk management work in Esquimalt Harbour is eligible under the Federal Contaminated Sites Action Plan (FCSAP) program. The presence of these contaminants and associated risks has also resulted in Esquimalt Harbour being classified as a Class 1 site (high priority for action) under Fisheries and Oceans Canada’s Aquatic Site Classification System. Managing these risks through remediation or other risk management measures supports DND’s environmental stewardship objectives.

The remediation of sediment is being completed through eight separate remedial projects. These projects are being completed by DND, with contracting through Public Services and Procurement Canada and Defence Construction Canada.

Remedial actions for the sites typically consist of remedial dredging with associated environmental controls and subsequent placement of clean backfill material. The extent of removal depends on working within the constraints of the active naval harbour, around functioning jetties, and considering the geotechnical aspects of Esquimalt Harbour. The goal of the remedial designs is to remove the extent of sediment contamination that exceeds project-specific thresholds while maintaining existing structures and protecting engineered slopes (e.g., riprap). To meet the remedial objectives, techniques focus on removal to the extent practicable to facilitate a reduction in DND liability and meet the objectives of the FCSAP funding source (i.e., addressing legacy contamination). Once removal actions have been completed, material placement actions are used to augment the removal actions and meet remedial objectives.

These remedial actions within Esquimalt Harbour flow into a Harbour-Wide Risk Management Plan that considers not only contamination from historic activities, but also the management of residual contamination, contaminants from non-point sources (e.g. storm water) and includes a monitoring program to confirm the effectiveness of the remedial and risk management actions over the long-term.

The project team and remedial designers have realized efficiencies through the multiple projects within the program. Lessons learned from completion of initial sites have and will continue to be incorporated into subsequent designs. Lessons learned include management of unexploded ordnance; identification and preservation of archaeological resources found; identifying opportunities for early action; and encountering variable bedrock surface depths.

Michael Bodman, Esquimalt Harbour Remediation Officer, Formation Safety and Environment, CFB Esquimalt, Department of National Defence
Michael Bodman, B.Sc., PMP, is the Esquimalt Harbour Remediation Officer at Maritime Forces Pacific based in Esquimalt, British Columbia. Michael has been an environmental professional for 19 years and is currently the Project Manager of the Esquimalt Harbour Remediation Project (EHRP). In addition to the EHRP-related duties, Michael provides environmental support to other major capital construction projects at Canadian Forces Base Esquimalt. He has also worked on a range of environmental programs related to environmental assessments, solid waste management, environmental audits, air quality and pollution prevention.

Design and Construction of Engineered Sediment Caps Using Activated Carbon Amendments for the Y Jetty/Lang Cove Remediation Project
Ross Pickering1, Michael Bodman2, Matt Woltman1, Tom Wang1, Derek Ormerod1, David Osguthorpe3, Kristen Ritchot3, Rae-Ann Sharp3 1Anchor QEA 2Department of National Defence 3Public Services and Procurement Canada
The objective of this presentation is to describe how in-situ treatment using activated carbon reduces the bioavailability of certain chemicals of concern, discuss the Y Jetty/Lang Cove site considerations that factored into the decision to use activated carbon in an amended sediment cap, and describe the design criteria. This presentation will also discuss the implementation challenges and lessons learned during construction of amended sediment caps at the site.  
Abstract

The Department of National Defense (DND) is undertaking a comprehensive sediment clean-up of 10 separate contaminated sediment sites in Esquimalt Harbour located in Esquimalt, British Columbia. The majority of aquatic lands in the harbour are owned and managed by the DND. The harbour has a long history of naval and industrial activity, both within the harbour and in the uplands along the shoreline. These activities have led to the presence of contaminants that exceed the probable effect level screening values set by the Canadian Council of Ministers of the Environment for the protection of aquatic life in sediment, including levels of metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, and dioxin/furans.

The Y Jetty/Lang Cove (YJLC) site, located on the southeastern shore of Constance Cove in Esquimalt Harbour, is the site of the former Yarrows Shipyard where past activities included shipbuilding and ship repair. Public Services and Procurement Canada (PSPC) administered the YJLC project in coordination with DND, with construction starting in fall 2018 and continuing through spring 2020. Remediation elements of the YJLC project include open-water and nearshore dredging and landfill disposal of approximately 52,000 cubic meters of contaminated sediment; construction of engineered sediment caps amended with activated carbon; and, management of dredge residuals through placement of residuals management cover material.

The inclusion of activated carbon as an amendment in engineered sediment caps has become a more accepted technology to address sediment contamination issues, particularly when contaminated sediment cannot be effectively removed due to restricted access or removal infeasibility. Use of these amendments provides more effective in-situ attenuation of certain contaminants (e.g., PAHs) with a potential net reduction in overall cap thickness, resulting in less net fill placed in sensitive aquatic environments. Activated carbon was used as an amendment in the engineered sediment cap design for the YJLC project in nearshore areas where dredging alone could not remove all of the contaminants at depth, or along the shoreline where areas of contaminated soil in inaccessible upland areas posed a groundwater recontamination risk to remediated sediment.

This presentation will describe how in-situ treatment using activated carbon reduces the bioavailability of certain chemicals of concern, discuss the project site considerations that factored into the decision to use activated carbon in an amended sediment cap, and describe the design criteria used. Applying activated carbon in the field as an amendment has unique challenges (e.g., unit density of activated carbon vs. cap materials). This presentation will also discuss the implementation challenges and lessons learned during construction of amended sediment caps at the YJLC project.

Ross Pickering, Senior Engineer, Anchor QEA, LLC
Ross Pickering, PE is a Senior Engineer at Anchor QEA, LLC, and has more than 14 years of experience focused on development of remedial designs for sediment, shoreline clean-up, and redevelopment projects. He has served as the Engineer of Record for the design and implementation of the YJLC project in Equimalt Harbour and lead design engineer for multiple large-scale aquatic site cleanup projects in Washington State, Oregon State, and western British Columbia. In addition to design development, Ross also leads construction management support services during construction.

A/B Jetty Sediment Contamination Resuspension Due to Rock Blasting: Modeling and Reality
Derek Ormerod1, Rebecca MacInnis2, Michael Bodman3
1Anchor QEA
2Defence Construction Canada
3Department of National Defence
The objective of this presentation is to review the results of post-blasting sediment sampling compared to the model predictions as part of the Department of National Defence’s A/B Jetty Recapitalization Project.  
Abstract

Addressing environmental risks associated with contaminated sediments in the Esquimalt Harbour is a high priority for the Royal Canadian Navy (RCN) and Department of National Defence (DND) based on the levels of contamination present and the potential for these sediments to result in human health and environmental risks. The harbour contains sediment contamination associated with industrial activity and naval operations. DND recognized the opportunity to remediate contaminated sediment adjacent to and under the A and B Jetty structures in conjunction with the A/B Jetty Recapitalization Project, which includes deconstructing and rebuilding these jetties. Remedial actions took advantage of the removal of structures to dredge the maximum extent of sediment contamination, thereby reducing DND’s corresponding liability.

In the B Jetty portion of this site, sediment remediation, consisting primarily of dredging, was conducted in 2017-2018. After dredging, a thin veneer of generated residuals consisting of fine-grained contaminated sediment remaining from dredging operations overlay the previously identified areas of bedrock. Moreover, due to the irregular surface of the bedrock, pockets of contaminated sediment were not successfully removed even after several rounds of dredging with a clamshell bucket. Bedrock blasting was then conducted in the winter of 2018-2019 and the summer of 2019 to allow for jetty construction and pile installation, and to achieve required berthing depths for current and future RCN vessels. Future clean material placement activities were intended to address the remaining contamination associated with the generated residuals and the remaining pockets of contaminated sediments.

As a risk mitigation measure Anchor QEA conducted modeling to aid DND in assessing the recontamination potential associated with blasting and redistribution of the remaining contaminated sediments. A hydrodynamic and sediment transport model was developed to conceptually predict the redistribution of sediment suspended during blasting. Modeling consisted of a combination of 2D hydrodynamic modeling to predict water surface elevations and tidal current velocities, combined with conceptual estimates of the mass and grain size of sediment suspended due to blasting. This information was used as input to predict potential spreading of the suspended contaminated sediment within the harbour.

Upon completion of blasting, Defence Construction Canada conducted sampling around the blast area and into adjacent previously remediated areas. This sampling was completed to identify the actual redistribution of contaminated sediment relative to pre-blast conditions. This presentation will discuss the results of the post-blasting sample collection and testing compared to model predictions and include lessons learned for future model refinement, noting areas of uncertainty in model inputs and outcomes. The presentation will also discuss mitigation strategies that may be implemented during construction to aid in the reduction of sediment redistribution.

Derek Ormerod, Senior Managing Engineer, Anchor QEA, LLC
Derek Ormerod, PE, is a Senior Managing Engineer at Anchor QEA, LLC, and has more than 20 years of experience with waterfront and aquatic projects, specifically remediation and restoration of previously impacted sites. Derek has managed and served as lead engineer for projects focusing on clean-up of aquatic sites, including design; impact assessment; remediation planning; delineation of impacted areas, and federal, provincial, and local permitting. He is very familiar with marine waterfront projects, working harbour operations, and remediation projects in these environments.

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