RPIC - Real Property Institute of Canada - Stream 2A - Esquimalt

Stream 1A Emerging Contaminants	Stream 1B Assessment
Stream 2A Esquimalt - Assessment	Stream 2B Esquimalt - Remediation	Stream 2C Esquimalt - Management/Monitoring
Stream 3 Remediation
Stream 4A Management	Stream 4B Assessment

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STREAM 2A
ESQUIMALT - ASSESSMENT

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Esquimalt Harbour Wood Waste Assessment, Characterization and Management Option Analysis
Sediment Recontamination Evaluation of Stormwater, Groundwater and Propwash, Esquimalt Harbour, Victoria, BC
Marine Archaeology and Seabed Remediation in Esquimalt Harbour, at the Esquimalt Graving Dock and Canadian Forces Base, Esquimal

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Esquimalt Harbour Wood Waste Assessment, Characterization and Management Option Analysis
Scott Northrup¹, Jamie Slogan¹, Mikaela Davis¹, Tim Abercrombie¹, Michael Waters², Ashley Rabey³¹Hemmera Envirochem
²Department of National Defence
³Public Services and Procurement Canada

The objective of this presentation is to demonstrate techniques for the assessment of aquatic habitats potentially affected by wood waste debris, present preliminary results on the potential negative effects to subtidal aquatic habitat function and recommended remedial options available given the findings of the assessment.

Abstract

Historical industry and associated activities, such as milling and log booming, have resulted in widespread woody debris and/or fibre blanket by-product areas in the subtidal zone of Esquimalt Harbour. Wood waste deposits can negatively affect seafloor flora and fauna by means of physical alteration of sediment characteristics, acute toxicity through production of leachate, and long term toxic effects associated with the by-products (i.e., hydrogen sulphide) of anaerobic decomposition. The assessment of the effects of wood waste on the marine environment is a priority for the Department of National Defence (DND) in alignment with the Esquimalt Harbour Remediation Project. To address this, the Esquimalt Harbour Wood Waste Assessment and Characterization Project was undertaken in fiscal year 2016-2017 by Public Services and Procurement Canada on behalf of DND. The objective of the Project was to determine the spatial extent, depth and composition of wood waste in Esquimalt harbour, determine the impacts to habitat quality and explore remedial or management options for the affected areas, including costs and the benefits and risks of each.

The Project included a combination of desktop-based work to review the existing biophysical information, historical activities, previous wood waste delineations and contamination information, and in-field surveys, to complete both biological and physical site characterizations and sediment chemistry analysis. In order to facilitate comparisons, in-field surveys focused on sampling four main conditions: (i) areas in Esquimalt Harbour affected by wood waste; (ii) areas in Esquimalt Harbour affected by fibre blanket; (iii) areas in Esquimalt Harbour not affected by wood waste; and, (iv) areas outside of Esquimalt Harbour where wood waste does not exist (control). Scuba transect surveys were undertaken in order to visually assess the extent of woody debris and fibre blanket and to conduct biological surveys on the current habitat conditions using the methodology developed by Fisheries and Oceans Canada which was the working draft of the Marine Foreshore Environmental Assessment Procedure. A sediment chemistry program was also developed in order to determine locations where wood waste or fibre blanket are impacting the habitat quality. Sediment samples (hand cores collected via scuba and grab samples) were analysed for total organic carbon, pore water sulphides, Ammonia, and pH.

Following data analysis, an impact assessment and management options analysis will be conducted and presented along with recommendations. Possible strategies for the management of affected sediments include: monitored natural recovery, enhanced natural recovery, capping, and dredging/removal. Each option varies in effectiveness and cost and depends on the wood waste extent and depth.

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Sediment Recontamination Evaluation of Stormwater, Groundwater and Propwash, Esquimalt Harbour, Victoria, BC
Todd Thornburg, Anchor QEA, LLC

The objective of this presentation is to provide an assessment of ongoing sources of contamination to Esquimalt Harbour associated with stormwater and groundwater discharges and propwash resuspension, and developing model predictions as to whether these ongoing sources are likely to cause recontamination of sediments in areas planned for in-water remediation.

Abstract

Background/Objectives

Esquimalt Harbour, located at the south end of Vancouver Island, British Columbia, is the primary Pacific homeport for the Royal Canadian Navy (RCN), with the majority of the aquatic lands in the harbour owned and managed by the Department of National Defence (DND). Addressing potential environmental and human health risks associated with contaminated sediments in Esquimalt Harbour is a high priority for the RCN and DND. Remedial actions are underway or in design for the more heavily contaminated areas of Esquimalt Harbour. To develop long-term risk management strategies within the context of this working maritime harbour, a sediment recontamination evaluation was conducted to inform DND of the potential for degradation of sediment quality following completion of remedial actions. The objectives of this study were to characterize and quantify contaminant mass loadings associated with stormwater, groundwater and propeller wash (propwash) sources in the harbour and develop long-term contaminant deposition models to predict whether sediment quality criteria are likely to be exceeded in the future, and if so, over what time frames,

Approach/Activities

The following potential recontamination pathways were evaluated: (1) stormwater discharges; (2) groundwater discharges from adjacent shoreline fill layers; and, (3) propwash resuspension of sediments from unremediated areas into planned remediation areas. The recontamination evaluation is supported by a compilation of recent stormwater data (30 outfalls), groundwater data (60 shallow shoreline monitoring wells) and sediment quality data; a two-dimensional hydrodynamic and sediment transport model of Esquimalt Harbour; and, a predictive sediment quality mass balance model. The primary contaminants of concern are metals (cadmium, copper, lead, mercury, and zinc), tributyltin, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). Propwash resuspension rates were estimated based on generalized vessel characteristics and tracklines, movement frequencies and predicted scour profiles.

Results/Lessons Learned

For stormwater sources, average model predictions (i.e., mean stormwater loads and mean sedimentation rates) as well as worst-case predictions (i.e., high-end loads or low-end sedimentation rates) resulted in future sediment concentrations stabilizing below sediment quality criteria, in many cases by an order of magnitude. Thus, stormwater discharges do not appear to pose a threat to long-term sediment quality in the harbour. For groundwater sources, average and worst-case model predictions similarly indicated a lack of sediment quality impacts, aside from a small area of interest near a former shipyard that may warrant additional investigation. Due to the frequency and large size of harbour vessel traffic, propwash resuspension rates are relatively high, indicative of vigorous sediment mixing and redistribution. In general, the mass loadings associated with propwash tend to overwhelm the combined stormwater and groundwater loadings. Contaminants with the highest sediment quality exceedances in outlying unremediated areas (mercury, PCBs, and copper) pose the highest risk of recontamination to the planned remediation areas via propwash. However, natural recovery is likely occurring in these areas, progressively reducing the source strength of the resuspended sediments. DND plans to develop a risk management plan to address any long-term residual risk and recontamination concerns in unremediated areas.

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Marine Archaeology and Seabed Remediation in Esquimalt Harbour, at the Esquimalt Graving Dock and Canadian Forces Base, Esquimalt
Charles Moore
Golder Associates Ltd.

The objective of this presentation is to present the results of recent archaeological work performed within the federally administered Esquimalt Harbour in British Columbia to support the remedial dredging of contaminated sediments. The focus of the presentation is on the tools and techniques to assess and mitigate significant pre-contact and historical archaeological sites, including shipwreck features, within the remediation areas.

Abstract

Recent seabed remediation work undertaken by Public Services and Procurement Canada, Defence Construction Canada and the Department of National Defence, has provided an opportunity for some exciting archaeological discoveries in Esquimalt Harbour, a federally administered harbour located in the Township of Esquimalt, British Columbia. Golder Associates Ltd. (Golder) has been pleased to offer a suite of heritage services within the contaminated sites program to assess and mitigate potential impacts to federally protected archaeological and historical sites.

The archaeological program began with an overview assessment conducted in advance of seabed remediation activities around the Esquimalt Graving Dock. This assessment established the archaeological potential for current seabed surfaces to have been former land surfaces (aerially exposed) at times of lower sea levels after the glaciers retreated from southern Vancouver Island, a period when archaeologists find the first physical evidence of human activity in the region. Part of the assessment involved a background review to determine which locations in the seabed remediation areas had been disturbed by previous industrial activities such as the construction of naval infrastructure and historical dredging. Careful analysis of historical charts and the results of previous geotechnical and geo-environmental borehole testing programs reveals that while much of the original coastline has been altered by various development activities, intact intertidal and subtidal deposits remained in the harbour that had potential to contain significant archaeological deposits.

Following the background overview, an innovative underwater testing technology, deployed in Canada for the first time, was used by Golder to verify the presence of archaeological materials, in place, underwater. Fragments of prehistoric basketry, possibly 7,000 years old, were discovered during this assessment program. Sediments were subsequently tested using specialized underwater and shallow water techniques in other intertidal and subtidal areas around the harbour. Underwater archaeological sites have now been identified and mitigated in several locations in the harbour.

The integration of archaeology into the remediation program has been completed with the full involvement of First Nations whose Reserve lands border the harbour. Their participation is helping Public Services and Procurement Canada and the Department of National Defence build a strong, respectful relationship with their First Nations neighbours, for whom the past, present and future use of the harbour is a key issue and concern.

Esquimalt Harbour is rich in historical archaeological resources. The harbour has been used for the last 150 years as a naval base, first by the Royal Navy, and after 1910, by the Royal Canadian Navy. Along with the naval presence, there have also been extensive civilian and private enterprises that used the harbour. The latter has left a ship graveyard, including the wreck of the Barbara Boscowitz. This vessel, built in 1883 and a significant pioneering vessel along the west coast of British Columbia, was discovered and documented during this program. The wreck of another “mystery” vessel has also been found in the same vicinity, and recorded using 3-D photogrammetry. Archaeological work has also recorded the abandoned remains of the 85-metre long cradle of a patent slip. The patent slip was a marine engineering wonder in the area when built about 1890, but forgotten with the construction of the Graving Dock 30 years later.

Golder will present some of the investigative techniques and results of its work over recent years in support of remediation in Esquimalt Harbour, including the methods used to determine archaeological potential of the intertidal and subtidal zones, underwater archaeological testing techniques, and a recently developed 3-D model of a shipwreck site.

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