April 20, 2009

Cambie Street Bridge Maintenance Activities, , BC

Submitted to:

Burrard Environmental Review Committee for Project Review

On Behalf of:

City of Vancouver Engineering Services - Structures Branch 453 West 12th Avenue Vancouver, BC V5Y 1V0 REPORT Report Number: 08-1421-0062 Distribution: 6 Copies - Burrard Environmental Review Committee 1 Copy - City of Vancouver 2 Copies - Golder Associates Ltd.

CAMBIE STREET BRIDGE MAINTENANCE ACTIVITIES

Limitations and Use of this Report

Standard of Care Golder Associates Ltd. (Golder) has prepared this report in a manner consistent with that level of care and skill ordinarily exercised by members of the engineering and science professions currently practicing in , subject to the time limits and physical constraints applicable to this report. No other warranty, express or implied is made.

Basis and Use of the Report This report has been prepared for the specific site, design objective, development and purpose described to Golder by the Client. The factual data, interpretations and recommendations pertain to a specific project as described in this report and are not applicable to any other project or site location. Any change of site conditions, purpose, development plans or if the project is not initiated within eighteen months, or a timeframe specified by regulatory agencies, of the date of the report may alter the validity of the report. Golder cannot be responsible for use of this report, or portions thereof, unless Golder is requested to review and, if necessary, revise the report.

The information, recommendations and opinions expressed in this report are for the sole benefit of the Client. No other party may use or rely on this report or any portion thereof without Golder’s express written consent. Golder will consent to any reasonable request by the Client to approve the use of this report by other parties as Approved Users. The report, all plans, data, drawings and other documents as well as all electronic media prepared by Golder are considered its professional work product and shall remain the copyright property of Golder, who authorizes only the Client and Approved Users to make copies of the report, and only in such quantities as are reasonably necessary for the use of the report by those parties. The Client and Approved Users may not give, lend, sell, or otherwise make available the report or any portion thereof to any other party without the express written permission of Golder. The Client acknowledges that electronic media is susceptible to unauthorized modification, deterioration and incompatibility and therefore the Client cannot rely upon the electronic media versions of Golder’s report or other work products. The report is of a summary nature and is not intended to stand alone without reference to the instructions given to Golder by the Client, communications between Golder and the Client, and to any other reports prepared by Golder for the Client relative to the specific site described in the report. In order to properly understand the suggestions, recommendations and opinions expressed in this report, reference must be made to the whole of the report. Golder cannot be responsible for use by any party of portions of the report without reference to the entire report. Unless otherwise stated, the suggestions, recommendations and opinions given in this report are intended only for the guidance of the Client in the design of the specific project. The extent and detail of investigations necessary to determine all of the relevant conditions which may affect construction costs, techniques and equipment choice, scheduling and sequence of operations would normally be greater than has been carried out for design purposes. Contractors bidding on, or undertaking the work, should rely on their own investigations, as well as their own interpretations of the factual data presented in the report, as to how conditions may affect their work.

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Table of Contents

1.0 INTRODUCTION ...... 1

2.0 REGULATORY SETTING ...... 1

2.1 Administrative Considerations ...... 1

2.2 Overview of Relevant Legislation ...... 2

2.2.1 Fisheries Act ...... 2

2.2.2 Navigable Waters Protection Act ...... 2

2.2.3 Canadian Environmental Protection Act ...... 2

2.2.4 Canadian Environmental Assessment Act ...... 2

3.0 SITE DESCRIPTION ...... 3

3.1 Habitats and Biota ...... 3

3.1.1 Site Description ...... 3

3.1.2 Aquatic Resources ...... 3

3.1.3 Terrestrial Vegetation and Wildlife Resources ...... 4

4.0 PROPOSED BRIDGE MAINTENANCE WORKS ...... 4

4.1 Rip-Rap Replacement ...... 4

4.2 Dredging ...... 5

4.2.1 Dredging Activities ...... 5

4.2.2 Sediment Chemistry ...... 5

4.3 Construction Schedule ...... 5

5.0 POTENTIAL IMPACTS ...... 6

5.1 Construction ...... 6

5.1.1 Site Preparation ...... 6

5.1.2 Fill and Rip-Rap Re-Instatement ...... 6

5.1.3 Cast-in-Place Concrete ...... 6

5.2 Dredging ...... 6

6.0 MITIGATION MEASURES ...... 6

6.1 General ...... 6

6.2 Cast-in-Place Concrete ...... 7

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7.0 ENVIRONMENTAL MONITORING AND SUPERVISION ...... 8

8.0 ENVIRONMENTAL PROTECTION PLAN (EPP) ...... 8

9.0 SUMMARY ...... 8

10.0 CLOSURE ...... 9

FIGURES Figure 1 Annotated Aerial Photograph Showing Location of Proposed Works Figure 2 Conceptual Illustrations of Bridge Remediation Measures Appendices

APPENDIX I Site Photographs

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CAMBIE STREET BRIDGE MAINTENANCE ACTIVITIES

1.0 INTRODUCTION On behalf of the City of Vancouver (CoV), Golder Associates Ltd. (Golder) is pleased to present the Burrard Environmental Review Committee (BERC) with this application for an environmental review of maintenance works at the south end of the Cambie Bridge in Vancouver, BC (Figure 1). The current incarnation of the Cambie Bridge was opened on December 8, 1985. It is a twin post-tensioned pre- stressed concrete continuous-span structure that extends across . The bridge’s total length is 1,100 m, and it carries six lanes of traffic and two pedestrian walkways. Following an inspection of the bridge piers in early 2008, MMM Group (the engineering consultants who designed the bridge) noted that supporting materials (i.e., rip-rap and quarry tailings) had eroded from beneath Pier W7 in the southern section of the bridge, and that sand had accumulated in an adjacent side channel. Although these issues do not mean the bridge structure is in immediate danger of collapse, the erosion of material from beneath Pier W7 has reduced the bridge’s seismic stability, and this issue must therefore be remedied to enhance public safety in the event of an earthquake. Furthermore, the erosion of material from beneath the bridge pile cap is readily visible to members of the public walking along the seawall, and this could lead to negative perceptions about the overall safety of the bridge. As a result of their inspection, MMM Group (2008) has made the following recommendations to the CoV regarding bridge maintenance:  Replace the rip-rap around Pier W7 to protect the pier footing and improve the seismic performance of the pier by adding passive resistance of the rip-rap layer;  Expose the drain pipe ends at Pier W6, extend the pipes beyond the rip-rap and replace the relocated rip- rap to its original configuration; and  Dredge the silted section of the side channel, re-establish the storm sewer outfall, and monitor sediment deposits from this sewer line.

The CoV has retained Golder to prepare a BERC submission for the proposed maintenance works. In addition to providing a description of the project, its biophysical environment, and anticipated environmental impacts, this application will propose environmental protection measures intended to minimize project-related impacts on aquatic and terrestrial habitats.

2.0 REGULATORY SETTING 2.1 Administrative Considerations Since the proposed project involves undertaking physical activities to seaward of the top-of-bank, the review of the project’s environmental effects will be coordinated by BERC, which is composed of representatives of the agencies that have a regulatory responsibility in Vancouver Harbour. These include Fisheries and Oceans Canada (DFO), Transport Canada, the BC Ministry of Environment (MOE), and the Vancouver Port Authority (VPA). BERC consists of the agencies responsible for environmental legislation and policy and land and water management in Burrard Inlet, to coordinate their planning and operational decision- making.

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2.2 Overview of Relevant Legislation The regulatory setting for this project includes the following federal statutes: 2.2.1 Fisheries Act The federal Fisheries Act is concerned with the management and protection of fish stocks that contribute to sport, commercial, and subsistence fisheries. Maintaining these stocks requires management of their biophysical habitat, and protection of fish populations from the negative effects of pollution. Fish depend directly or indirectly on their biophysical habitats for spawning, nursery and rearing grounds, migration routes, and food supplies. Section 35(2) of the Fisheries Act prohibits the “harmful alteration, disruption, or destruction” (HADD) of fish habitat, unless authorized by DFO. The National Policy for the Management of Fish Habitat (DFO 1986) outlines the objectives and procedures that DFO follows in managing habitat. A major theme of this policy is that there be “no net loss” of habitat, and DFO’s preference is that projects be designed at their outset such that a HADD is avoided. Although the proposed work is maintenance work and not an expansion, the proposed works involve physical activities in an area considered to be fish habitat and review by DFO is therefore appropriate. Should DFO determine that an Authorization is required, DFO (and by extension the project proponent) is required to conduct a screening-level environmental assessment of the project under the Canadian Environmental Assessment Act (CEAA).

2.2.2 Navigable Waters Protection Act The Navigable Waters Protection Act (NWPA) was enacted to keep Canadian waters safe for vessel navigation, and to ensure that physical works do not impede navigation. The need for a NWPA permit is determined through the review of a project by Transport Canada. As with the Fisheries Act, an authorization under the NWPA is a trigger for a screening-level assessment under CEAA.

2.2.3 Canadian Environmental Protection Act Under the 1999 Canadian Environmental Protection Act (CEPA), disposal of dredged material at sea requires a permit under Environment Canada’s Disposal at Sea Permit System. Because this is a federal permit, disposal at sea projects are automatically subject to a screening-level review under CEAA.

2.2.4 Canadian Environmental Assessment Act The determination of whether or not this bridge maintenance project will require an Authorization or Letter of Advice from Fisheries and Oceans Canada (DFO) under the Fisheries Act, and/or a permit from Transport Canada under the Navigable Waters Protection Act (NWPA) will be reached by BERC agencies during their review. The requirement of either a Fisheries Act Authorization, or a permit under the NWPA, triggers the need for a screening of the project under the Canadian Environmental Assessment Act (CEAA). If required, a CEAA screening will be conducted within context of the BERC review. The need for a permit from Environment Canada for the ocean disposal of dredged material will trigger a CEAA screening. At present, it is unclear if Environment Canada continues to carry out work through BERC or if they will undertake their screening independently of BERC, within their Disposal at Sea Permit Process.

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3.0 SITE DESCRIPTION The remedial activities are proposed to occur at the southern end of the Cambie Bridge (Figure 1). Specifically, the study area consists of the areas surrounding the bases of Bridge Piers E7 and W7 (Photographs 1 and 2).

3.1 Habitats and Biota 3.1.1 Site Description The Cambie Bridge and eastern basin of False Creek are located in the Coastal Western Hemlock (CWH) biogeoclimatic zone. This zone occurs from low to middle elevations along the entire BC coast, and is the wettest in the province. The climate in the CWH zone is temperate and characterized by mild, wet winters and cool, dry summers (Meidinger and Pojar 1991). Natural CWH forests are dominated by western hemlock (Tsuga heterophylla), Douglas-fir (Pseudotsuga menziesii), and western redcedar (Thuja plicata). However the area surrounding the eastern basin of False Creek has been completely developed as an urban area during the last century, and the all of the original vegetation has been removed and replaced with paving, buildings, and urban parks containing lawn and ornamental deciduous tree and shrub species. The shoreline at the southern end of the Cambie Bridge is completely man-made, and consists of a rip-rap armoured sea wall.

False Creek is an important commercial and recreational waterway that provides moorage and loading/off- loading. As a consequence of adjacent urban development, the marine habitat of False Creek has been dramatically altered from its original (i.e., pre-urbanized) condition. The waters of False Creek are derived from the Strait of Georgia, which in turn are protected from the high winds and waves of the Pacific Ocean by Vancouver Island.

3.1.2 Aquatic Resources False Creek lacks natural nearshore habitats and, compared to pristine coastal environments, has relatively poor water quality and low marine biodiversity. Most of the False Creek shoreline is composed of anthropogenic fill material (Golder 1998a,b). According to a subtidal biophysical inventory provided by Forsehore Technologies (1996) the predominant substrate type is mud and sand, with the finer substrate located centrally in the channel (Photograph 3). Only recently have habitat restoration activities been undertaken in the basin (e.g., along the Southeast False Creek development shoreline). The intertidal zone in the vicinity of the Piers W7 and E7 consists of rip-rap that is encrusted with large numbers of blue mussels (Mytilus edulis), and lesser numbers of barnacles (Balanus sp.) (Photograph 4). Other species that were not observed, but which are probably present, include shore crabs (Hemigrapsus oregonensis) and various other marine invertebrates. A narrow band of rockweed (Fucus sp.) is apparent in the high intertidal zone. The depositional area to the east of Pier E7 is covered with clam shells, but no clams were observed within the sediments during sediment sampling on September 25, 2008. A list of the marine plant, invertebrate and fish species that potentially occur in False Creek is provided in Appendix I. This list was developed from Snively (1978), and is a list of species typically found in intertidal and subtidal habitats in the Pacific Northwest. The list of potentially occurring fish species is based on the experience of Golder personnel and Gehlen (1995), and should not be considered comprehensive, nor is it based on recent site-specific surveys. However, Golder believes that it provides a sufficient level of information for decision-making in this instance.

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3.1.3 Terrestrial Vegetation and Wildlife Resources The False Creek seawall occupies the terrestrial habitat adjacent to the proposed work site. No backshore vegetation is present. Wildlife species which use this highly urbanized environment include crows (Corvus caurinus), rock pigeons (Columba livia), English sparrows (Passer domesticus), and Norway rats (Rattus norvegicus). The marine environment of False Creek has considerable year-round boat traffic, but nonetheless provides habitat for disturbance-tolerant species such as gulls (Larus spp.), great blue herons (Ardea herodias), cormorants (Phalacrocorax spp.), Canada geese (Branta canadensis) and other water bird species such as ducks and grebes.

4.0 PROPOSED BRIDGE MAINTENANCE WORKS 4.1 Rip-Rap Replacement Two bridge piers, W7 and E7, are located on the south bank of False Creek. Significant scour has taken place at the foot of Pier W7, and loss of the rip-rap armouring has exposed many of the steel pipe piles below the footing (Photograph 1). The mud line in the northwest corner of the footing with Pier W7 is showing much more extensive scour than when it was originally constructed, and the distance between the underside of the footing and the mud line is currently estimated to be >3 m. In terms of vertical support of the bridge, this level of scour is not a significant concern, provided the exposed pipe piles are not damaged, because the original design intent was for all the vertical loading to be taken by the steel pipe piles. However, the lateral load capacity of the footing is significantly reduced, and this is of particular concern when considering seismic influences. Pier E7 does not exhibit the same amount of scour as Pier W7, although the northwest comer of the footing shows receding rip-rap. The localized deposition of sediments (Photographs 2, 3) in the side channel between pier lines 6 and 7 is thought to protect Pier E7 and contribute to the accelerated scour of Pier W7, as this ‘bank’ has resulted in an alteration to the local water movement around these pier footings. Maintenance works associated with rip-rap installation will be done at low tide, and will involve:  Site preparation through partial removal of existing rip-rap and quarry tailings from beneath the existing pile cap using a small excavator (e.g., a “Bobcat”).  Placement of the required amount (estimated to be 800 m3) of clean quarry tailings beneath the pile cap.  Construction of concrete formwork around the “void” beneath the pile cap, which is to be filled with cellular concrete.  Applying “shotcrete” to create a “floor” to the void.  Filling the void with light-weight cellular concrete (approximately 90 m3).  Installation of storm drain pipe extensions at the bridge piers, so that they will be long enough to extend beyond the rip-rap layer.  Placement of new rip-rap (approximately 400 m3).

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4.2 Dredging 4.2.1 Dredging Activities Dredging is required to remove approximately 980 m3 of accumulated sand from the side channel between pier lines 6 and 7 (Photograph 2), where it has buried the piers’ drainage pipes and a storm sewer outlet. Because of the relatively small volume of material that will be dredged, and because of the potential difficulty in operating a clamshell dredge under the bridge, dredging will be done using a barge mounted excavator. Because the proposed dredge site is situated adjacent to a navigable waterway (i.e., False Creek), disposal of the dredgeate at sea is preferable to land disposal due to the increased cost of shipping the material for land disposal. Dredge spoils can be simply loaded onto a barge and transported to the disposal location, as opposed to requiring multiple truck trips to a land disposal facility.

4.2.2 Sediment Chemistry In order to obtain a Disposal at Sea Permit from Environment Canada, it is necessary to characterize the contaminant concentrations of the material to be dredged through an approved sampling program conducted under Environment Canada supervision. A sampling plan prepared by Golder (Appendix 1) was approved by Environment Canada, and the sampling program was conducted on September 25, 2008 under the supervision of Environment Canada personnel. Three composite samples were taken and analysed for mercury, cadmium, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and dioxins and furans. The concentration of these compounds in the samples did not exceed Environment Canada’s “Disposal at Sea” criteria. The next step in this process will be the submission to Environment Canada of an application for disposal at sea. As the permit is only valid for one year, the application should only be submitted once the project timeline is known. For this reason, the City of Vancouver wishes to have confidence that other aspects of environmental approvals are near completion.

4.3 Construction Schedule The construction schedule for the proposed bridge remediation works is currently unknown, but will be constrained by the following factors:  This project requires a daytime low tide interval sufficiently low and long that the site can be accessed to do the work. The mid-day low tides that occur in May, June, and July are preferable as they provide the most favourable working conditions.  The “Marine Timing Window” is the period of the year during which Fisheries and Oceans Canada considers construction work in the marine environment will have a reduced risk for causing harm to commercial, sport and resident fish species. In the Lower Fraser Area, this window extends from August 16 to February 28 the following year.  Timeframe for obtaining Disposal at Sea Permit from Environment Canada. This can take up to an estimated 3.5 months.

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5.0 POTENTIAL IMPACTS 5.1 Construction 5.1.1 Site Preparation Site preparation will require partial removal of the existing rip-rap, which will result in the temporary loss of habitat colonized by organisms such as barnacles, mussels, and macroalgae. However, this habitat loss is expected to be temporary because these types of organisms will rapidly re-colonize the site once work is complete.

5.1.2 Fill and Rip-Rap Re-Instatement The planned works will result in a footprint similar to that occupied by the bridge footings as they were originally built. The design specification for the work specifies that clean (i.e., washed) quarry tailings and rip-rap will be used, and work will be done during the low-tide period when the work site is dry. Siltation and disturbance to fisheries is therefore expected to be minimized through this approach.

5.1.3 Cast-in-Place Concrete While concrete is a safe and reliable construction material, casting concrete in-place carries the potential risk of the leakage of alkaline materials from the uncured concrete into the marine environment. These materials are toxic to fish and other aquatic life as a result of the corrosive pH produced. However, there are established procedures that can be used to mitigate the potential adverse effects of concrete. These are described in Section 6.2.

5.2 Dredging The dredging program will result in the removal of approximately 980 m3 of intertidal sand. Suitable containment measures will be required when the dredging occurs to ensure that sediments re-suspended in the water column do not escape. Provided these measures are applied, significant environmental effects are not expected.

6.0 MITIGATION MEASURES 6.1 General The potential adverse environmental effects associated with rip-rap placement and remedial dredging can be avoided or minimized through the development and implementation of effective environmental management and emergency response plans during all phases of construction. The following key mitigation strategies would be employed to prevent or minimize disturbance or environmental impacts to aquatic resources and habitats within and adjacent to the project area:  These works will only be done when the site is dry, during the low-tide period.  Ideally, the works would be planned to coincide with the marine fisheries window so that resource species (primarily migratory salmon) will not be impacted by localized turbidity that might result from the tidal inundation of the work area. However, because the ideal tides for doing this work are outside the fisheries window, this is not desirable. To mitigate turbidity -related impacts, sediment and erosion control measures

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(e.g., a silt fence or curtain around the dredging area) will be used as required to minimize the potential for sedimentation. Should DFO require it, fish sampling will be undertaken before the work occurs, and the work may be delayed if concentrations of juvenile salmonids are present.  Equipment and machinery will be maintained in good operating condition, and cleaned of excess or visible mud and grease by power washing. Any equipment refueling that takes place on the barge will be done with a spill containment kit readily available in case of accidental spills.  A spill containment kit will be readily accessible on-site in the event of a release of hydrocarbon to the environment. The contractor should refer to Schedule of Reportable Levels for Certain Substances in the Spill Reporting Regulation of the provincial Waste Management Act). Any spills will be immediately reported to the Provincial Emergency Program 24 hour phone line at 1-800-663-3456;  Rip-rap and quarry tailings used for this project will be inert, free of contaminants and will be placed so that it will not gain entry into False Creek.  A copy of these recommended mitigation measures/best management practices, and appropriate plans, drawings and documents will be forwarded to the contractor/crew supervisor and will be readily available at all times at the site while the work is proceeding;  Construction activities will be monitored as necessary by an appropriately qualified professional(s). The environmental monitor(s) will be provided with written authority to modify and/or halt any construction activity if deemed necessary for protection of fish and wildlife populations or their habitats; and,  A pre-construction meeting will be held between the environmental monitor and the contractor undertaking the work on the site to promote an understanding of the mitigation measures/best management practices for the project.

6.2 Cast-in-Place Concrete  All cast-in-place concrete work must be carefully planned out in advance of the commencement of construction. All work areas must be isolated from the water. The contractor should plan how the forms will be constructed, how the concrete will be delivered without spillage to the area in question, and how the poured concrete will be kept isolated from the marine waters of Burrard Inlet before and during curing.  Forms must be prepared with tight joints, and if the uncured concrete could contact water during tidal fluctuations, the form joints will be sealed and open surfaces covered with polyethylene to prevent exchange of water with uncured concrete. Prior to the concrete pour, a plan will be discussed with the environmental monitor and amended as required.  In the event that cast-in-place concrete cannot be isolated or must be installed below the water surface (all work is to be completed at low tide), the work area must be isolated using polyethylene tarps. Water contained within the work area will be tested for pH and if greater than 9.0 pH units, gaseous carbon dioxide (CO2) will be applied to the enclosed area, through a diffuser structure, until the pH is less than 9 relative units but greater than 7. An environmental monitor with properly calibrated field pH measuring equipment must be present during such work.  A supply of compressed carbon dioxide, together with necessary pressure regulators, shut-off valves and bubbling fixtures must be available on site when concrete work is being performed along the shoreline.

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7.0 ENVIRONMENTAL MONITORING AND SUPERVISION All works in the intertidal area will be carried out in the presence of a qualified environmental monitor. The monitor will be responsible for liaising with the contractor to plan the execution of physical works in the intertidal area, so that impacts are minimized to the extent possible, and to monitor the attainment of conditions of approval. As the application of cementitious materials within the intertidal zone is a necessary component of this work, the monitor will also be responsible for having properly calibrated instruments capable of measuring pH to ±0.2 relative units. The monitor will confirm with the contractor that gaseous carbon dioxide and a means of administering the carbon dioxide are available on-site and ready for deployment if pH results indicate that it is necessary. If monitoring or inspection observations indicate that the construction activities are not consistent with the terms and conditions of permits or approvals, or that there is imminent risk of such an occurrence, and that this cannot be mitigated, then the environmental monitor will direct the contractor to suspend work. The environmental monitor will be furnished with a letter from the City of Vancouver providing the authority to do so. The environmental monitor will be responsible for providing the contractor with a written daily environmental monitoring report, communicating with the contractor regarding environmental issues that need to be resolved and will also be responsible for providing reports to agencies as required by those agencies (e.g., daily, weekly, etc.). Copies of all reports will also go to the City of Vancouver’s project manager.

8.0 ENVIRONMENTAL PROTECTION PLAN (EPP) The project, once initiated, will be completed as quickly as possible. In addition to the mitigation strategies outlined above, the contractor will be required to prepare an EPP which will address applicable regulatory requirements. The site works will not start unless this plan is reviewed by the environmental monitor. The implementation of the EPP will be monitored throughout the duration of construction as noted in Section 7.0.

9.0 SUMMARY The CoV needs to undertake maintenance works at the south end of the Cambie Bridge, where supporting materials (i.e., rip-rap and quarry tailings) have eroded from beneath Pier W7 and sand has accumulated in an adjacent side channel. The CoV intends to replace the lost rip-rap; expose and extend the drain pipe ends at Pier W6; and dredge the 980 m3 of material from the silted section of the side channel. Ocean disposal of the dredged material is proposed, since concentrations of contaminants in the material do not exceed Environment Canada’s “Disposal at Sea” criteria. The construction schedule for the proposed work is currently unknown, but the preferred tides for doing the bridge maintenance works occur in May, June, and July. The work site in False Creek has poor water quality and low marine biodiversity when compared to a pristine coastal environment. The intertidal biota of the bridge piers consists mainly of encrusting mussels and barnacles, with a narrow band of rockweed in the high intertidal zone. The depositional area to the east of Pier E7 consists mainly of sand, which probably supports a fauna of burrowing organisms. Potential environmental effects related to the proposed bridge repair works include:  A loss of habitat colonized by encrusting organisms, which is expected to be temporary because these types of organisms will rapidly re-colonize the site after the work is complete.  Increased turbidity around the work site, which can be mitigated by conducting the work at low tide, and by using silt fences if required.  Potential interaction between uncured concrete and the marine environment could result in fish mortality. Suitable containment and mitigation measures will be applied to avoid this occurrence.

Suitable containment measures will be used when the dredging occurs to prevent the escape of sediments that become re-suspended in the water column.

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10.0 CLOSURE We trust that the above information is sufficient for your review and comment on the proposed Cambie Bridge stabilization and dredging. If you have any questions, or require additional information, please contact us at your earliest convenience.

Paul McElligott, Ph.D., R.P.Bio. Lee Nikl, M.Sc., R.P.Bio. Senior Scientist Associate

PM/LHN/jc

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PROJECT CITY OF VANCOUVER CAMBIE STREET BRIDGE MAINTENANCE ACTIVITIES VANCOUVER, BC TITLE Annotated Aerial Photograph Showing Location of Proposed Works

PROJECT No. 08-1421-0062 PHASE No. DESIGN JC 20APR09 SCALE NTS REV. CADD JC 20APR09 CHECK FIGURE 1 REVIEW

CAMBIE STREET BRIDGE MAINTENANCE ACTIVITIES

APPENDIX I Site Photographs

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APPENDIX I Photographs

Photograph 1: Scour Area

Photograph 2: Depositional Area

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APPENDIX I Photographs

Photograph 3: Sand Substrate in Depositional Area

Photograph 4: Intertidal Substrate

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Golder Associates Ltd. 500 - 4260 Still Creek Drive Burnaby, British Columbia, V5C 6C6 Canada T: +1 (604) 296 4200