Environmental Management Strategy for Dredging in the Fraser River Estuary

Transcription

1 Environmental Management Strategy for Dredging in the Fraser River Estuary It has been several years since the Fraser River Estuary Management Program (FREMP) provided a review of navigation and dredging activities in the Fraser River estuary. The last review, conducted in 1991, resulted in a FREMP report entitled Navigation, Dredging and Environment in the Fraser River Estuary (FREMP, 1991). Since this report, several significant changes have occurred with respect to navigation and dredging in the estuary. With the new Canada Marine Act in 1998, the federal government no longer dredged the lower river, and in the interests of their tenants and business operations, the Ports began dredging the main navigation channel. The Ports have since pursued funding to allow a long-term dredging program in the lower Fraser River. In 1998, FREMP developed a Sediment Budget to ensure sustainable sediment removal for the lower river, and annually reports on dredging activities and sediment removals. In 2001, FREMP produced Dredge Management Guidelines for dredging proponents, and in 2002 the Sediment Budget model was reviewed and confirmed as an appropriate sediment management tool. Trends in navigation include increasing container traffic through Greater Vancouver ports and marine terminals are expanding at Roberts Bank, Port North Fraser, and in the Fraser River Port to accommodate that growth. Ships are also becoming much bigger, and the main navigation channel in the Fraser has been deepened to accommodate their access upriver to key port facilities. Use of the river is becoming more intensive, diverse and valued, including an increasing population s demand for riverfront residential and recreational areas. Consolidation of industrial operations, such as in the forest sector, has led to land uses changes along the river, in some cases with new residential developments replacing former sawmills. More parks have been established in the estuary, along the water or in park reserves like Douglas Island. The focus has moved from preserving industrial lands along the river to focusing on critical strategic nodes for intermodal movements and short-sea shipping. Fewer on-land dredge disposal sites mean that most sediment dredged from the river goes to ocean disposal. For those remaining on-land disposal sites, sediment dredged from the river has to be moved longer distances to reach the disposal sites. Navigation, Dredging and the Environment The lower Fraser River provides a waterway for the transport of over 50 million tonnes of coastal and deep sea cargo annually. It also supports as many as 650 million young 1

2 salmon migrating downstream and up to 10 million spawning salmon every year as well as other important fish species such as eulachon and white sturgeon. The estuary is a major stopping point for migrating birds on the Pacific flyway including the largest population of wintering waterfowl in Canada. River uses and marine transportation generate demands for development and maintenance of navigation channels. The dredging program varies depending on annual sedimentation and navigation requirements. Dredging activities are also currently managed to avoid conflict with fisheries resources and aquatic habitat, mainly by limiting dredging to specific locations and through the use of scheduling and timing restrictions. The interdependencies between these components of the management system require a continual balancing of objectives, which the FREMP partners try to achieve through their policy coordination and project review functions. Estuary Management Plan The Estuary Management Plan for the Fraser River was updated in 2003 and includes a Navigation & Dredging Action Program with two objectives: 1. To develop and maintain a functional navigation system that support waterdependent development in a manner that protects environmental quality; and 2. To manage the removal of sediment from the river in a manner that balances with all components of the sediment budget of the river system. One of the actions in the Estuary Management Plan is to develop a comprehensive dredge management strategy for the estuary that will provide a contextual framework regarding the navigation system s relationship with the environment, review existing studies relating to dredging impacts, and recommend areas in the estuary requiring further study. This document is intended to fulfil this action, and provide a means to help manage the dredging system in the estuary. In 2004, FREMP completed a review of data needs with respect to the biological impacts of dredging in the estuary. The findings of this work have been incorporated into the Environmental Management Strategy for Dredging in the Fraser River Estuary, which outlines recommendations for further study in each reach and thereby provides a policy framework to end uncertainties associated with site-by-site requirements for habitat studies. The Strategy will help proponents understand their responsibilities when applying for approval of dredging projects, facilitate the FREMP Environmental Review Committee evaluation of dredging applications, and ultimately, ensure that dredging in the estuary proceeds in an environmentally sustainable manner. The approach taken recognizes the differences between annual maintenance dredging, periodic dredging and new dredging applications. The Strategy is a companion document to the FREMP Dredge Management Guidelines (Revised 2005), which describe the Fraser River Sediment Budget and are a resource for proponents preparing dredging applications for review through the FREMP Environmental Review Committee. This document forms part of an overall consideration 2

3 of dredging activities in the Fraser River estuary, focusing on the environmental component. It does not address issues such as physical changes in the river, trends in navigation, and the beneficial use of dredgeate. Acknowledgements The Report is a joint effort of a FREMP Water and Land Use Committee working group comprised of staff with dredging knowledge and expertise, including: Environment Canada Fisheries and Oceans Canada Canadian Coast Guard, Waterways Development Fraser River Port Authority North Fraser Port Authority Ministry of Environment This document was drafted by FREMP dredging working group members with support from FREMP staff, reviewed by the FREMP Water and Land Use and Environmental Review Committees, and approved by the BIEAP-FREMP Management Committee in January Report Structure The Environmental Management Strategy for Dredging is an assessment of the river by channel segment. For the nine segments, the Strategy identifies major natural features, port activities and industrial uses, the status of environmental knowledge about dredging impacts, and data gaps. Appendices contain background information including an overview of the estuary, port operations, dredging and environmental issues. 3

4 PART 1 - Dredging Strategy for Each Channel Segment The FREMP area of interest includes the land and water outside the dikes and between Kanaka Creek and the outlet of Pitt Lake in the East, the estuary drop-off in the West, Point Grey to the North, and the international boundary to the South, including Boundary Bay and Semiahmoo Bay. For purposes of this dredging strategy, the estuary is divided into nine channel segments as noted on the following page, extending from the Sand Heads Lighthouse upstream to the eastern end of Barnston Island. These segments are based on channel morphology, water quality, tidal influence, and the effect of major channel-training works. Each section that follows includes the following information: An overview of the channel segment including major functions and industry type and water lots; A review of Port and dredging activities within the channel; The status of our environmental knowledge vis-à-vis biological impacts of dredging in that channel, including data gaps, mitigation measures, ongoing studies and environmental sensitivities. In terms of the environmental management approach to dredging, in all channel segments dredging is managed in a way that avoids or minimizes adverse impacts to the environment. Timing restrictions are applied to hydraulic suction dredging and large clamshell dredging projects to avoid entrainment of juvenile salmonids and eulachon. Dredging is also required to be conducted in a manner that minimizes the release of suspended sediments in the water column and in a manner that does not disturb intertidal vegetation. These requirements are set out in the FREMP Dredge Management Guidelines (2005) and through the Coordinated Project Review process through FREMP. 4

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6 1. NORTH ARM TIDAL Channel Segment Overview The North Arm segment is split around Sea Island (Vancouver International Airport). The majority of flow is carried in the north branch (about 10% of total Fraser River flow) and the water is brackish in quality. This segment is channelized but not heavily industrialized, with much of the shoreline park, golf courses or included in the Sea Island Conservation Area on the north side of Sea Island. Highly productive shoreline is present, especially in the river mouth and estuary where Iona Island (north branch) and Swishwash Island (middle branch) are found. A channel is maintained by direction of flow on the north side of the North Arm Jetty, but substantial deposition still occurs at the river mouth. Salmonid fish utilization within the segment is largely confined to adult holding and migration in the fall and downstream juvenile migration and rearing in the spring to midsummer periods. The North Arm Tidal also supports several other species of fish including an annual upstream eulachon spawning migration in the spring, surf smelt spawning, and white sturgeon. The eulachon run and surf smelt spawning attracts marine mammals including seals and sea lions. Information on fish species utilization of the Segment can be found in Appendix 2. 6

7 Waterfowl utilization (e.g. roosting and feeding) is most concentrated in intertidal marshes and mudflats along the shoreline, although some diving ducks utilize deeper water for foraging for fish. Port Activities within the Channel Segment Within the North Arm, log booms are transported from coastal harvest areas into the estuary (for processing at lumber and paper manufacture mills) and lumber, pulp chips and wood by-products (e.g. sawdust and hog fuel) are transported out for use at other locations. The North Arm is the main transport route for log booms, being a shorter distance to up-river mills. Cement and aggregates, fish distribution and processing, and general freight are also important but in much less tonnage than forestry related cargo. The Middle Arm provides concentrated pleasure craft moorage. Commercial fishing also occurs within the port, particularly by the Musqueam First Nation. Dredging Activities Dredging is not carried out regularly in this segment. Infrequent maintenance dredging occurs at the upstream end of Sea Island and the North Arm Jetty; this includes maintaining boat access to channels on both sides of Sea Island and supporting log storage leases and tugboat access to the Point Grey log booming grounds, a long term storage area providing freshwater storage for the forestry sector to prevent marine borers from ruining the logs. Once every five years or more, maintenance dredging also takes place at barge load/unloading facilities, sawmill sites, and so forth. Status of Environmental Knowledge A dredging data needs study through FREMP identified several feasible data needs for the North Arm Tidal segment. The data needs identified included: An assessment of the impacts of dredging on the abundance and distribution of resident demersal fish in bar habitat where dredging of bar habitat is proposed. An assessment of the impacts of dredging on the abundance and distribution of benthic invertebrates. Data has not been compiled for this segment, however a study has been conducted in the Sand Heads segment (Taylor and Perrin, 2005). The Sand Heads segment may be sufficiently similar to the North Arm Tidal segment in which case results from the study could be extrapolated to the North Arm Tidal segment (see Section 3). While the study in the Sand Heads segment only includes an assessment of the impacts of dredging on the abundance and distribution of benthic invertebrates (i.e. abundance and distribution of resident demersal fish in bar habitat is not being addressed), it should be noted that bar habitat, as well as the need to dredge bar habitat, in the North Arm Tidal segment is relatively rare. Should any large scale dredging projects that may need to be undertaken on a frequent basis involving bar habitat be proposed, further information to address the above data need should be collected and/or assessed. 7

8 2. NORTH ARM MESO-TIDAL Channel Segment Overview The North Arm Meso-Tidal channel segment extends from New Westminster Quay to the eastern end of Sea Island. Historically, it conveyed less than 10% of total Fraser River discharge, but installation of training structures that started in the 1930s have increased the flow to %. This has increased channel flow and reduced sediment deposition. This segment flows through the heavily urbanized areas of Burnaby, Vancouver, New Westminster, and Richmond, and receives discharges from industrial and municipal sources. Historically, there were several major industrial discharges which have since have been discontinued due to closing of industrial operations or installation of improved waste water processing. It is assumed that the lower water quality has improved over historical conditions, but there has not been extensive water quality monitoring to show current conditions. Because of the heavy urbanization, productive fish and wildlife habitat is limited to narrow areas of riparian vegetation and intertidal marsh along the shoreline including the North Fraser Port Authority's Fish Habitat Compensation Bank. A large area of highly productive fish and wildlife habitat in the Segment can be found in the City of Burnaby's Terminus Park in the Big Bend area of the River. 8

9 Salmonid fish utilization within the segment is largely confined to upstream adult migration in the fall and downstream juvenile migration and rearing in the spring to midsummer periods. The Segment also supports several other species of fish including an annual upstream eulachon spawning migration in the spring and white sturgeon. The eulachon run attracts marine mammals (e.g. seals and sea lions). Information on fish species utilization of the Segment can be found in Appendix 2. Waterfowl utilization (e.g. roosting and feeding) is mostly concentrated in intertidal marshes and mudflats along the shoreline, although some diving ducks utilize deeper water for foraging for fish. Port Activities within the Channel Segment Log booms are transported from coastal harvest areas into the estuary (for processing at lumber and paper manufacture mills) and lumber, pulp chips and wood by-products (e.g. sawdust and hog fuel) are transported out for use at other locations. The North Arm is the main transport route for log booms, being a shorter distance to up-river mills. Cement and aggregates, fish distribution and processing, and general freight are also important but in much less tonnage than forestry related cargo. Commercial fishing also occurs within the North Fraser Port, particularly by the Musqueam First Nation. Dredging Activities This segment is characterized by infrequent navigational channel dredging, but dredging is vital for port operations, and has been a maintenance activity since the port began in The main channel extends along the North Arm upriver from the mouth, south of Mitchell Island upstream to 22 nd Avenue past the Queensborough Bridge in New Westminster, where it joins the Fraser Port-administered channel. Main channel maintenance dredging is required periodically at critical points in the harbour (e.g. upstream of Mitchell Island). These points must be maintained but they generally do not result in large volumes of dredged material. Maintenance dredging for barge load/unloading facilities, sawmill sites, terminals, recreational docks and so forth, usually occur on a greater than five year cycle. There is infrequent operation of one transfer pit located at the Big Bend (see below). Infrequent and localized clamshell dredging takes place in association with industrial sites to maintain access for industrial boat traffic. Another important dredging activity is forestry industry support, which includes dredging to support log handling areas at sawmills and access for tugs. A transfer pit at Burnaby Big Bend was established in 1990 and was again used in to transfer sand from St. Mungo s Bend in the South Arm to a property in south Burnaby. This project may be ongoing and involve the transfer of 100, ,000 m 3 of sand pumped upland each year for several years. The pit will be backfilled by hopper dredge using sand from Annieville Channel and St Mungo s Bend in the South Arm Meso-Tidal segment. Immediately upstream was the site of Caisson dredging that was completed in 2003 to remove contaminated sediment. Maintenance dredging typically occurs upstream of Poplar Island and in the vicinity of Mitchell Island. 9

10 Status of Environmental Knowledge A dredging data needs study through FREMP identified several feasible data needs for the North Arm Meso-Tidal segment. The data needs identified included: An assessment of the impacts of dredging on the abundance and distribution of resident demersal fish in deep thalweg habitat. An assessment of the impacts of dredging on the abundance and distribution of resident demersal fish in bar habitat where dredging of bar habitat is proposed. An assessment of the impacts of dredging on the abundance and distribution of benthic invertebrates. An assessment of dredging impacts on benthic communities to address some of the above data needs is ongoing in the North Arm Meso-Tidal segment. This study, funded by Fraser River Pile & Dredge, is associated with the operation of a transfer pit at Big Bend. Sampling took place in November 2003 and in May 2004 following dredging in January To date, researchers have found a decline in catchable fish in relation to site disturbance, and the site appears to be remaining in disturbance three months after dredging occurred. The apparent dredging effect may be due to less mobility of fish into and outside of the dredging area that may cause slow recruitment back into the dredge site after disturbance. However, the data also suggests that resident fish re-colonized the transfer pit within four months after dredging. While the above study will address a number of data gaps for the North Arm Meso-Tidal segment, a remaining feasible data need is: An assessment of the impacts of dredging on the abundance and distribution of resident demersal fish in bar habitat where dredging of bar habitat is proposed. However, bar habitat, as well as the need to dredge bar habitat, in the North Arm Meso- Tidal Segment is relatively rare. Should any large scale dredging projects that may need to be undertaken on a frequent basis involving bar habitat be proposed, further information to address the above data need should be collected. 10

11 3. SAND HEADS Channel Segment Overview The Sand Heads channel segment extends west of Steveston to the end of the Steveston Jetty and provides the main access into the Fraser River for large ships. Being at the mouth of the Fraser River, it has a much more marine environment than the upstream channel segments. The Steveston North Jetty is a 8.8-km long rock mound training dyke that extends to the Sand Heads light house and assists in maintaining an outflow channel, however dredging is still required on a regular basis to maintain channel depth. Past dredging that resulted in removal of 400,000 m 3 /year was costly and lead to modification of the Jetty to improve sand transport by river flow. A wall was constructed along the inside curve of the Steveston Jetty to maintain current velocity and encourage scouring. However, the deflection simply moved sand deposition further downstream, and annual dredging is still required. The channel in the Sand Heads Segment is being deepened in 2004 through 2006 to facilitate an increase in vessel draft from 10.7 m to 11.5 m. Because the Segment is bounded laterally by training structures, fish and wildlife habitat in the Segment is limited. Salmonid fish utilization within the Segment is largely 11

12 confined to adult holding and upstream migration in the fall and downstream juvenile migration in the spring to mid-summer periods. The Segment also supports several other species of fish including various marine fish species, an annual upstream eulachon spawning migration in the spring, sandlance which are an important forage fish, and white sturgeon. The eulachon run attracts marine mammals including seals and sea lions. Information on fish species utilization of the Segment can be found in Appendix 2. Waterfowl utilization is limited given the limited present of intertidal marshes and mudflats along the shoreline. Some diving ducks may utilize deeper water for foraging for fish. Port Activities within the Channel Segment The Sand Heads segment is the entry into Fraser Port, and is characterized by dense and varied marine traffic including deep-sea ships, commercial fishing boats, barges and tugs. Dredging Activities This segment is characterized by frequent main channel dredging of more than once a year, with use of a hopper dredge and ocean disposal of material. The deep-sea ships entering the navigation channel require a draft of 11.5 m to reach the upstream end of the shipping channel 36kms later at New Westminster. Infrequent use of a cutter suction dredge also takes place with ocean disposal of material. Status of Environmental Knowledge A dredging data needs study through FREMP identified several feasible data needs for the Sand Heads Segment. The data needs identified included: An assessment of the impacts of dredging on the abundance and distribution of resident demersal fish in deep thalweg habitat. An assessment of the impacts of dredging on the abundance and distribution of resident demersal fish in bar habitat where dredging of bar habitat is proposed. An assessment of the impacts of dredging on the abundance and distribution of benthic invertebrates. An assessment of fish (Sandlance) entrainment during dredging. In 2004, a study was undertaken by the FRPA to address some of the above data gaps at Sand Heads (Taylor and Perrin, 2005). Sampling took place in February and April 2004, with dredging in March Results showed no consistent difference between control and dredge sites with regards to changes in the catch rate of sandlance, other fish species or density of benthic invertebrates between February (before dredging) and April (after dredging). The results therefore indicate that any effect on benthic fish and benthic invertebrates is very short term, with rapid recruitment into the dredged sites after disturbance. While the above study addresses a number of data gaps for the Sand Heads segment, a remaining feasible data need is: 12

13 An assessment of the impacts of dredging on the abundance and distribution of resident demersal fish in bar habitat where dredging of bar habitat is proposed. However, bar habitat, as well as the need to dredge bar habitat, in the Sand Heads segment is relatively rare. Should any large scale dredging projects that may need to be undertaken on a frequent basis involving bar habitat be proposed, further information to address the above data need should be collected. 13

14 4. SOUTH ARM TIDAL Channel Segment Overview The South Arm Tidal segment extends from Steveston to the west end of Deas Island. It has a maintained navigation channel along the north bank, an estuarine wetland and island-complex along the south bank - home of the renowned George C. Reifel Migratory Bird Sanctuary on Westham Island and South Arm Marshes Wildlife Management Area (WMA). The segment is highly influenced by tidal action and the intrusion of salt water throughout its length. The South Arm Marshes WMA is an island-complex that includes high quality inter-tidal marsh habitat and mudflats. Major training works maintain the navigation channel through the Woodward Reach, where flow splits between the island-complex and Canoe Pass (around Westham Island). The training structures were installed between 1922 and 1948 to stabilize island banks and sand bars, and contributed to the formation of this productive aquatic habitat. They also provide flood protection for Ladner. Channel deepening is occurring in this segment in 2004 through 2006 to facilitate an increase in vessel draft from 10.7m to 11.5m. Salmonid fish utilization within the Segment is largely confined to upstream adult migration in the fall and downstream juvenile migration and rearing in the spring to midsummer periods. The Segment also supports several other species of fish including an 14

15 annual upstream eulachon spawning migration in the spring and white sturgeon. The eulachon run attracts marine mammals (e.g. seals and sea lions). Information on fish species utilization of the Segment can be found in Appendix 2. Waterfowl utilization (e.g. roosting and feeding) is mostly concentrated in intertidal marshes and mudflats along the shoreline, although some diving ducks utilize deeper water for foraging for fish. Port Activities within the Channel Segment Key activities in the South Arm Tidal segment are deep sea shipping in the navigation channel, commercial fishing hubs located in Steveston and Ladner harbours, fish processing facilities and marinas. Commercial, First Nations and recreational fishing takes place throughout this segment, including areas in and around the West Arm Marshes and Canoe Pass between Westham Island and Delta. Dredging Activities Very frequent maintenance dredging of the navigation channel occurs, primarily by hopper dredge, especially in Steveston Cut. The hopper delivers sand to the Sand Heads ocean disposal site or to transfer pits located upstream. There is also infrequent and localized clamshell dredging to maintain boat access to moorage in small craft harbours, mainly in areas of Ladner and Steveston. Infrequent clam shell/cutter suction dredging of secondary channels takes place in Ladner Reach and Sea Reach to maintain navigation for small vessels; proponents dredging their water lots to maintain access. Status of Environmental Knowledge Studies in the South Arm Tidal segment include a study of the environmental effects of harbour construction activities at Steveston, BC (Anderson et al., 1981). The study found that the subtidal silt benthic invertebrate community repopulated a small dredged area within one month after dredging stopped. A dredging data needs study through FREMP identified a feasible data need for the South Arm Tidal segment as: An assessment of the impacts of dredging on the abundance and distribution of resident demersal fish in bar habitat where dredging of bar habitat is proposed. However, the need to dredge bar habitat in the South Arm Tidal segment is relatively rare. Should any large scale dredging projects that may need to be undertaken on a frequent basis involving bar habitat be proposed, further information to address the above data need should be collected. 15

16 5. SOUTH ARM MESO-TIDAL Channel Segment Overview The South Arm Meso-Tidal segment is a channel confined by bank protection and training structures. This segment conveys approximately 80 to 85% of total Fraser River discharge downstream of the trifurcation. The segment includes Deas Slough, a centre of recreational boating activity, as well as Gunderson Slough and Tilbury Slough in Delta which are both characterized by shallow bars at their mouth. The main navigation channel moves from Gravesend Reach through St Mungo s Bend on the south side of Annacis Island, and upriver through Annieville Channel. Much of the reach is industrialized activity along the shoreline, as reflected in the relatively higher percentage of FREMP green-coded shoreline. The South Arm Meso-Tidal also contains the New West Trifurcation training structure, which splits the flow down multiple channels and serves to decrease sedimentation, thus reducing dredging requirements. Fish and wildlife habitat in the main channel primarily consists of a narrow band of riparian and intertidal marsh vegetation along the shore. Productive habitat is present is sloughs such as Deas Slough and Tilbury Slough. Salmonid fish utilization within the segment is largely confined to upstream adult migration in the fall and downstream juvenile migration and rearing in the spring to midsummer periods. The segment also supports several other species of fish including an 16

17 annual upstream eulachon spawning migration in the spring and white sturgeon. The eulachon run attracts marine mammals (e.g. seals and sea lions). Information on fish species utilization of the segment can be found in Appendix 2. Waterfowl utilization (e.g. roosting and feeding) is mostly concentrated in intertidal marshes and mudflats along the shoreline, although some diving ducks utilize deeper water for foraging for fish. Port Activities within the Channel Segment This segment contains three deep-sea terminals: Fraser Wharves has one berth, Annacis Auto Terminals has two berths for automobiles, and Fraser Surrey Docks has three container berths, three general cargo berths and one side-loading berth (from river to ship, or vice versa). FRPA Richmond Properties at the foot of Broad Street is an industrial park containing marine related facilities, with a large portion of waterfront property slated for deep sea terminal. Several other industries are located at or adjacent to the Surrey Properties including a lumber mill, steel processor, and distribution centres for specialty grains, forest products and rolled paper. BC Ferries has a ferry maintenance slip in Deas Basin on the north side of the river in Richmond. Dredging Activities Annual maintenance dredging with the hopper and cutter suction dredge occurs at several locations within the segment. Sand is delivered to transfer pits located throughout the estuary for disposal at sea or upland. St. Mungo s Bend and Annieville Channel near Fraser-Surrey Docks are two sites where regular dredging is necessary to allow access by large ship traffic. Two transfer pits are present within the lower segment in the vicinity of Tilbury Island. Frequent operation of these transfer pits occurs, from which sand is pumped to upland sites for market sales using a cutter suction dredge. Infrequent and localized (no more than once every five years) clamshell dredging takes place to maintain boat access to small craft harbours (e.g. Gunderson Slough) and for boat and barge access (e.g. Burr Landing near the mouth of Tilbury Slough which was dredged in the late 1990s) and moorage (Seaspan Coastal Intermodal, BC Ferries Deas Basin, Delta Cedar, and Bella Coola Fisheries). The mouths of Tilbury and Gunderson Sloughs or adjacent areas have been dredged in the past for vessel access to moorage and will likely require ongoing dredging in the future. Status of Environmental Knowledge A dredging data needs study through FREMP identified several feasible data needs for the South Arm Meso-Tidal segment. The data needs identified included: An assessment of the impacts of dredging on the abundance and distribution of resident demersal fish in bar habitat where dredging of bar habitat is proposed 17

18 An assessment of the impacts of dredging on the abundance and distribution of benthic invertebrates. Studies in the South Arm Meso-Tidal segment include an assessment of sturgeon habitat at Fraser Surrey Docks by ECL-Envirowest for Berth 10 (ECL Envirowest Consultants Ltd., 2001). However, the assessment did not include an assessment of environmental effects of dredging as part of Berth 10 construction. Another study conducted in the Segment includes a pre and post dredge benthic assessment of Deas Basin (Prime Eight Consulting, 2001). The study found impacts to benthic invertebrate and benthic fish after dredging but the study did not continue to determine if impacts continued over the long term. A study has also been completed in the Barnston segment (Perrin et al., 2003 and Perrin and Rempel, 2000), and the Barnston segment may be sufficiently similar to the South Arm Meso-Tidal segment in which case results from the study could be extrapolated to the South Arm Meso-Tidal segment. Of the above two data needs, the study in the Barnston channel segment only included an assessment of the impacts of dredging on the abundance and distribution of benthic invertebrates. While the study included a review of resident fish for that segment, it did not include an assessment of the impacts of dredging on the abundance and distribution of resident demersal fish in bar habitat where dredging of bar habitat is proposed (since Barnston is not characterized by bar habitat). It should be noted that, while bar habitat in the South Arm Meso-Tidal segment is relatively rare, bar habitat does exist at the entrance to Gunderson Slough and Tilbury Slough (Burr Landing) where dredging may need to occur in the future. In the past, dredging at these two sites has occurred on an infrequent basis and involved relatively low volumes of dredge material. Should any large scale dredging projects that may need to be undertaken on a frequent basis involving bar habitat be proposed, further information to address the above data need should be collected. 18

19 6. ANNACIS CHANNEL Channel Segment Overview Annacis channel extends from the upstream end of Annacis Island (Shoal Point) downstream to Lafarge Canada west of Lion Island and conveys approximately 5 to 10% (design conveyance) of total Fraser River discharge downstream of the New Westminster trifurcation. Annacis Channel flows for 7 km on the north side of Annacis Island and is approximately m wide. This channel is very different from Annieville Channel and St. Mungo s Bend south of Annacis Island, in that Annieville Channel and St. Mungo's Bend has extensive picket fence and continuous fence training works that maintain velocities and minimize dredging needs. Annacis Channel has no training works. The bed sediment has a finer grain size than main channel, possibly the result of the New Westminster trifurcation upstream. The Annacis Channel Segment includes Lion and Don Island park reserves, which have been protected through an intergovernmental purchase and provide critical habitat for fish and wildlife. Log booms are present over shallow mud-bottom habitat along the south shore. About 55% of the segment shoreline is red-coded with high biological values based on the presence of riparian trees, intertidal marsh and mudflat habitat. This red-coded area encompasses Patrick Island Foreshore Reserve on the north side of Annacis Island. 19

20 Salmonid fish utilization within the segment is largely confined to upstream adult migration in the fall and downstream juvenile migration and rearing in the spring to midsummer periods. The segment also supports several other species of fish including an annual upstream eulachon spawning migration in the spring. The eulachon run attracts marine mammals (e.g. seals and sea lions). Information on fish species utilization of the segment can be found in Appendix 2. Waterfowl utilization (e.g. roosting and feeding) is mostly concentrated in intertidal marshes and mudflats along the shoreline, although some diving ducks utilize deeper water for foraging for fish. Port Activities within the Channel Segment Annacis Channel is home to a number of industrial and commercial businesses as well as floathomes. Marine traffic in the segment is varied: recreational and fishing vessels, tugs, barges and log storage as well as mills. Dredging Activities The channel thalweg is 9 15 m deep with velocities up to 9 knots during freshet, which appears to maintain channel depth. Little or no channel dredging is required on an annual basis. Channel dredging was last active in 1995, but some areas are filling in and may require dredging in the future. Log booms currently ground at low tide and it has been suggested that, if the log cannot be relocated to deep water, dredging be undertaken to allow tug access and log boom transport at all tides. Very frequent clam shell dredging (at least once per year and probably more) is used at localized areas along the south shore to prevent grounding of barges and allow small tug access to booming areas. There is a main channel in-river disposal site just off Lion and Don Islands, which is in a scour zone. Status of Environmental Knowledge A dredging data needs study through FREMP identified several feasible data needs for the Annacis Channel segment. The data needs identified included: An assessment of the impacts of dredging on the abundance and distribution of resident demersal fish in thalweg habitat where dredging of thalweg habitat is proposed. An assessment of the impacts of dredging on the abundance and distribution of resident demersal fish in bar habitat where dredging of bar habitat is proposed. The Annacis Channel segment may be quite different from the adjacent South Arm Meso-Tidal segment - because dredging is infrequent and the effects of disturbance may be large, with long time periods for recovery between disturbance events. The finer sediments in the Annacis Channel segment may also lead to different effects from 20

21 dredging compared to that found in the main stem Fraser River. In this channel segment a better understanding of the impacts of dredging on the abundance and distribution of resident demersal fish in thalweg habitat and in bar habitat is needed. Should any large scale dredging projects that may need to be undertaken on a frequent basis be proposed in the Annacis Channel Segment, further information to address the above data needs should be collected. 21

22 7. SAPPERTON Channel Segment Overview The Sapperton segment is characterized by a single-thread channel that is sharply confined upstream at the Port Mann Bridge and downstream at the Patullo Bridge. The channel is moderately confined along its entire length by rock armoured banks. There is limited riparian habitat and tidal influence is substantial without presence of brackish water. The segment is considered to have moderate water quality, being upstream of the majority of heavy industry and effluent discharges. A V-shaped deflection dyke installed in 1936 has created an artificial zone of deposition referred to as Sapperton Bar, where log sorting and booming occurs. Continual sediment deposition has led to the need for recent dredging to maintain sufficient water depths for log sorting and storage. The V-dyke and two wing dykes in the Sapperton segment are critical to maintaining flow and self-scouring, but no agency is currently responsible for maintaining them. Tree Island, immediately upstream of the Port Mann Bridge and opposite the Coquitlam River confluence, is a natural depositional feature that differs in sediment grain size texture and general morphology from Sapperton Bar. The Sapperton segment is highly industrialized on both sides of the river, including several mill sites. Developed areas on the Surrey side include the CN Rail Intermodal yards. The Coquitlam/New Westminster side is characterized by major log sorting and booming operations. 22

23 Sapperton Bar in the segment provides important habitat for fish and wildlife. Salmonid fish utilization within the segment is largely confined to upstream adult migration in the fall and downstream juvenile migration and rearing in the spring to mid-summer periods. The segment also supports several other species of fish including an annual upstream eulachon spawning migration in the spring. The eulachon run attracts marine mammals (e.g. seals and sea lions). Information on fish species utilization of the segment can be found in Appendix 2. Waterfowl utilization (e.g. roosting and feeding) is mostly concentrated in intertidal marshes and mudflats along the shoreline, although some diving ducks utilize deeper water for foraging for fish. Resident and migratory birds utilize river and upland habitat for feeding, nesting and raising young. Of particular importance is the heronry at the Coquitlam River Wildlife Management Area, with over 100 active nests. The Coquitlam floodplain forest forms a part of the remaining natural corridor connecting the Coquitlam River, Colony Farm, Douglas Island and Surrey Bend. The combination of varied habitat along the corridor supports a high diversity of birds and wildlife. The Sapperton segment has the highest proportion of green-coded (low productivity) shoreline in the estuary. Port Activities Sapperton Bar is a key log sorting and booming area on the river. Moorage exists for tugs and barges, and marine traffic includes recreational and fishing vessels, tugs and a variety of barges and scows (break bulk, bulk, container and log). Mill activity is prominent, and a number of barge ramps are in place. Dredging Activities This segment is characterized by infrequent navigational channel dredging. There has been channel maintenance dredging in the north channel, along with infrequent log-sort and maintenance dredging. Cutter-suction dredging/scalping of shallow bars and access channels - to allow access by small tugs for moving and sorting log booms - occurs on a very infrequent basis, no more than once every ten years. The north side of the Sapperton segment may be dredged in the future. Proposed dredging at the outflow of the Coquitlam River is on hold due to outstanding unresolved issues over a historical site. Status of Environmental Knowledge With respect to dredging of shallow bar habitat (cutter suction dredging), the Sapperton segment is sufficiently understood. A dredging impact assessment funded by Fraser River Port Authority has recently been completed at Sapperton Bar in the channel segment. The project involved assessments of: 23

24 the impacts of dredging on the abundance and distribution of resident demersal fish in bar habitat, the impacts of dredging on the abundance and distribution of benthic invertebrates. The project involved sampling in 2002 and 2003 followed by laboratory and data analyses in 2004, and included the collection of benthic invertebrates, turbidity observations and fish data collection in the area both before and after dredging. Detailed study results are presented in Taylor et al., However, in summary, the study found that: no impacts of dredging were detected on the benthic invertebrate or resident fish communities at Sapperton Bar. Their findings suggested that the biological communities were highly resilient, with recovery through re-colonization completed in less than 3.5 months after dredging was completed. eulachon may swim through the Sapperton Bar area enroute to spawning sites upstream and would not be affected by modified substrate depths caused by dredging events several months earlier. the distinctive community structure, diversity and abundance of benthic invertebrates and fish at Sapperton Bar appears resilient to dredging at the scale that was tested in the project, and that this feature of the site seems due to the geomorphological attributes of bar habitat. For large scale dredging projects proposed in the Sapperton channel segment, no further information is required to be collected. 24

25 8. LOWER PITT RIVER Channel Segment Overview The Lower Pitt River is a tributary to the Fraser River that drains Pitt Lake - the largest freshwater tidal lake in North America - and its upper watershed. The channel segment begins north of Douglas Island, at the confluence of the Pitt and Fraser Rivers, and continues north to the mouth of Pitt Lake. Differences between the Pitt River and Fraser River in water quality, suspended sediment load, organic matter content, bed substrate, and flow regime are expected but unconfirmed. Although there is low sediment transport from the Pitt River, a reverse delta does occur due to tidal backwater effects in the area just upstream of the Pitt s confluence with the Fraser River. As witnessed by the high proportion of FREMP red-coded shoreline habitat, highly productive wetland and riparian habitats are present on both sides of the Pitt River, particularly in the upper part of the channel segment around the Pitt-Addington Marsh Wildlife Management Area and in the lower reach on the eastern bank in Pitt Meadows. The segment is home to a large number of resident bird species such as herons, hawks, passerines and waterfowl, and is an important stopover point on the Pacific Flyway for migratory birds. Waterfowl utilization (e.g. roosting and feeding) is most concentrated in 25

26 intertidal marshes along the shoreline, although some diving ducks utilize deeper water for foraging for fish. The Pitt segment also supports runs of sockeye, coho, pink, chum, and chinook salmon. Salmonid fish utilization within the segment is largely confined to upstream adult salmonid migration in the fall and downstream juvenile migration and rearing in the spring to mid-summer periods. The channel also supports several species of non-game fish, including eulachon which use the lower Pitt River for spawning and white sturgeon. Seas and sea lions migrate to the area during the spring eulachon migration. Information on fish species utilization of the segment can be found in Appendix 2. More information is also available in the Pitt River Reach Overview on the FREMP website. Port Activities within the Channel Segment Some industrial development occurs in the Lower Pitt River and it is a log boom staging area, particularly in the area below the rail and highway bridges. The channel segment is occupied by small vessel and float home marinas, boat and barge moorage, mill sites, barge ramps, aggregate supplies as well as log storage and dewatering sites. Boat traffic consists of pleasure boats, water sports, tug boats, log tows and rock scows. The deeper tugs and scows that operate in this reach require 4.5m of depth to operate safely. The Fraser-Pitt corridor is an important navigation route for tug and vessel traffic, including transport of log booms to processing mills. Two major towing operations, Harken Towing and Forrest Marine, are located along the Lower Pitt River. Waterrelated commercial and residential development occurs in Port Coquitlam along the river, and new residential development is planned on the former Genstar lands in Pitt Meadows. Log booms are located along much of the shoreline. Dredging Activities Dredging is not carried out regularly in this segment. While significant dredging took place in the Pitt River segment between 1970 and 1996, the Lower Pitt River is now characterized by infrequent navigational channel dredging. Maintenance of barge load/unloading facilities, marinas and so forth occurs approximately on a five year cycle or longer. There is infrequent clamshell dredging (more than every 5 years) to maintain moorage depths for boats using the Alouette Marina and Pitt River Boat Club and for vessels using barge loading ramps associated with a gravel pit operation run by Lehigh on the western bank of the Pitt River in Coquitlam, and the Pitt River Quarries (Warren Paving and Materials) facility on the east side in Pitt Meadows. A transfer pit has been identified in the Lower Pitt River but is not in use at present and was last used in There is potential to use it again if demand arises, as the pit was backfilled with high quality sand. Status of Environmental Knowledge A dredging data needs study through FREMP identified several feasible data needs for the Lower Pitt River segment. The data needs identified included: 26

27 Abundance and distribution of eulachon An assessment of the impacts of dredging on the abundance and distribution of resident demersal fish in bar habitat where dredging of bar habitat is proposed. An assessment of the impacts of dredging on the abundance and distribution of benthic invertebrates. Under high frequency stress, a system has less opportunity to recover fully so each successive event changes the system less. The Lower Pitt River segment may be quite different from the Fraser River - because dredging is infrequent and the effects of disturbance may be large, with long time periods for recovery between disturbance events. The low natural turbidity in the Lower Pitt River segment may also lead to larger effects from turbidity and suspended sediment generated during dredging compared to that found in the main stem Fraser River. In this channel segment a better understanding of the impacts of dredging on the abundance and distribution of eulachon, resident demersal fish in bar habitat, and benthic invertebrates is needed. Should any large scale dredging projects be proposed in the Lower Pitt River segment, further information to address the above data needs should be collected. 27

28 9. BARNSTON Channel Segment Overview The Barnston channel segment begins in the east where Kanaka Creek meets the Fraser River, continuing around both sides of Barnston Island to encompass the west side of Douglas Island park reserve. The segment is characterized by an irregular meandering morphology with major islands and associated side channels. Vegetated riverbanks and islands provide riparian habitat although riprap occurs along many sections of the shoreline. Water quality is generally good and industrial activity is relatively low. Tidal influence on flow and water depth is present but diminishes at the upstream end. Channel narrowing at the Port Mann Bridge causes a backwater effect extending upstream, which favours deposition of sand and silt. The segment is characterized by small industrial operations including sawmills, in Parson s Channel between Surrey and Barnston Island. Halo Sawmills and Fraser River Log Salvage are the two main industrial operations on the Pitt Meadows side, along with the Pitt Meadows Airport. On the south bank, the CN Intermodal yard extends from the Port Mann Bridge to Surrey Bend Regional Park. A major CP Intermodal yard is located in Pitt Meadows near the confluence of the Fraser and Pitt Rivers. Agricultural operations exist on Barnston Island and Pitt Meadows where adjacent land use within the dykes includes berry framing and hay crops. 28