Conservation Priorities in the Squamish River Estuary To: Squamish Estuary Conservation Society

2.2 Current Threats

Since 1973, several toxic chlorinated hydrocarbons (e.g., PCB, DDE, heptachlor epoxide and dieldrin) have entered estuaries and coastal areas of the Georgia Straight. Toxins can be quite elevated near pulp mills. For example levels were so high at Crofton in the mid 1980s that they affected the fledging success of great blue heron chicks that were being studies at the time (see Mahaffy et al. 1994). Similarly, a health advisory was issued with regards to consumption of western grebe and common merganser livers in 1990 because contamination levels were high in Howe Sound due to effluents from two bleached kraft mills. A health advisory was issued on Vancouver Island, downstream from a pulp and paper mill because of high PCDD and CDF residues in common mergansers, surf scoters, and western grebes, as well as in the surficial sediments and some resident amphipod species. Water of the Squamish estuary should be monitored regularly for contamination from commercial and industrial sources: Nexen site, Empire Logging hogfuel storage site, and Mamquam Channel log handling facilities. There have been two shellfish harvest closures in Howe Sound, one as a result of elevated mercury levels, and the other a consequence of high dioxin concentrations (Goldsmith, pers. com.).

The construction of the training dyke, port and rail spur line, and the dredge-and-fill operations associated with the development of current industrial sites within the estuary, have: (1) destroyed many hectares of sensitive habitat; (2) modified hydrologic conditions; (3) affected water quality; and (4) altered biotic communities.

2.2.1 Heavy Industry

The West Barr log sort is located in a section of salt marsh at the very centre of the estuary. In addition to eliminating the productive capability of the marsh areas impacted, the unprotected banks are subject to the erosion and subsequent infusion of sediments into the central channel. Surface compaction caused by operation of heavy equipment on the decking area, combined with rainfall causes significant amount of runoff into the estuary, that carries suspended sediments as well as organic leachates and wood fibers. Log rafts, particularly during their handling, can also introduce soluble organic compounds into the water. These leachates increase benthos oxygen uptake, decrease dissolved oxygen, lower pH, increase volatile solids, increase toxic sulfide compounds, increase water coloration, and change the physical composition of the substrate (see Gaumer et al. 1985). Leachates in very high concentrations are lethal to juvenile salmonids (see Gaumer et al. 1985). For example, tannic acid is toxic to some species of fry, such as Chinook. Log rafts and their associated pilings are energy dissipaters that slow water velocity and thus increase the rate of sediment deposition in the area (see Gaumer et al. 1985). Log rafts block sunlight that normally strikes the water column and substrate of shallow intertidal zones. Their impact depends on raft size and duration of storage. Also, substrate alteration (sedimentation compaction, grinding, and churning) arises when rafts rest on the bottom at low tide, and from tugboat handling of logs. Substrate disturbance has a high impact on the microorganisms and the food webs they support (Gaumer et al. 1985). The noise associated with log rafting and storage displaces much terrestrial and aquatic wildlife. In 2014, this log sort will be moved from the centre of the estuary, to Site B at the mouth of the Mamquam Blind Channel, on the eastern (outer) shore of the estuary. Although the relocation will benefit salmonids in the new DFO channels as well as the majority of staging and wintering water birds, it will still cause the loss of productive mudflat, seagrass and saltmarsh habitats on the eastern shore, and a subsequent decline in all associated species. The new log handling facility, however,). Mamquam Channel currently has the largest biomass of overwintering and migrating birds during mid winter and late spring (see Table 1).

The sawmill on Mamquam Blind Channel were, and may still be very contaminated because lumber used to be dumped into an open pit of highly toxic preservative prior to shipping, to prevent them from becoming mouldy (Greenpeace water quality testing; Len Goldsmith, pers. com.). Similarly, the Nexen chemical plant site is very contaminated; warehouses containing toxic dredge spoils from the area are currently being shipped away via the rail line. Soils at the head of the Blind Channel are filled with toxic leachate from Empire Logging’s improperly stored hogfuels in the past. The water is showing signs of stabilizing (Edith Tobe, pers. com.).
Dredging the Blind Channel will cause the release of toxins that have been stored in bottom sediments over the years. Other negative effects of dredging include increases in turbidity, oxygen depletion, entrainment of aquatic species, and burial of subtidal habitats, wetlands and adjacent uplands (Emmet et al. 2000). Positive benefits of dredging are short-term, and include enhanced productivity, improved circulation and increased usage of the water body in question. A deep-sea port at the mouth of the Blind Channel would necessitate extensive dredging of the Blind Channel for ship navigation. Such a port will also cause erosion of the shoreline, and will eliminate what remains of deltaic habitat for waterbirds in the area.

2.2.2 Proposed Commercial/Industrial Zone and Transportation Corridor

The Squamish Estuary Management Plan proposes to establish an industrial/commercial zone along the eastern edge of the newly zoned provincial Wildlife Management Area (east of the BCR railway and terminal). A transportation corridor is proposed between this industrial/commercial area, and the Wildlife Management Area (Squamish Estuary Coordinating Committee 1999). This road would parallel the most western rail line, and access the Central Channel just south of the Terminals. It would also branch off through Bridge Pond (just north of the municipal storm water retention pond known as Stinky Lagoon) and lead to Main Street, thereby redirecting heavy traffic (i.e., commercial vehicles) around rather than through the town centre. There is no proposed buffer between the southwest end of this road and the large bend of Crescent Slough; nor is there an adequate buffer along Cattermole Slough and the East Delta in general. Roads built along the estuary perimeter increase the chance of an accidental introduction of toxic materials to the estuary, such as spills of petroleum products. A paved surface will increase the storm run-off from the road and from the urban, commercial and industrial centres it bisects, increasing the probability of toxic input into the estuary (Kennish 2002). Although the chemicals may affect only a localized area, they can be transported to adjacent estuarine water with outgoing tides. There is no buffer between the end of this proposed road and the Wildlife Management Area boundary in Central Channel, which implies that direct toxic spills into the estuary are possible at that location. Riparian buffers and infiltration ponds can protect a wetland by trapping and filtering run-off; they should be maintained along all watercourses and unclassified channels within the estuary area, and along its entire periphery. Forested riparian buffers are particularly valuable because they can also provide wildlife with visual separation and a buffer from noise pollution. A forest buffer is imperative in areas of moderate to high human activity (e.g., downtown area), and areas of moderate to high wildlife value (e.g., Bridge Pond, East Marsh). Riparian buffers in the 1999 Squamish Estuary Management Plan are grossly inadequate at ensuring stormwater detention and purification, providing habitat for riparian-dependent species, and buffering wildlife from human activities. The proposed retention of two small, non-wind firm tree patches next to this transportation corridor (along the northern most section of Crescent Slough and along a portion of Cattermole Slough) will not suffice to separate the estuary from the town centre.

2.2.3 Storm run-off and Sewage Infrastructure

Based on water tests conducted by Greenpeace at the request of a concerned citizen (Len Goldsmith, pers. com.), the storm run-off retention pond contains elevated concentrations of toxins from municipal run-off.

To protect water quality, sewage should undergo tertiary treatment prior to its release into the estuary. The release of partially treated sewage can significantly increase nutrient levels in estuaries; it can degrade water quality by raising biochemical oxygen demand, promoting eutrophication problems, and delivering chemical contaminants and pathogenic microorganisms such as bacteria and viruses (Kennish 2002). Biotic communities exposed to high levels of pollutants can exhibit loss of rare species, decreased species abundance, shifts in the age structure of populations, and altered trophic interactions. The entire ecosystem can be disrupted by these changes.

2.2.4 Recreation

Estuaries are becoming increasingly popular destinations for recreationists. Recreation threats in the Squamish Estuary include invasion of wildlife habitats by: (1) hikers along improperly planned or overly extensive trail networks, (2) motorized vehicles, especially motor cross bikes; (3) non-motorized and motorized watercraft use within estuary channels and in the Squamish River; (4) windsurfing and kite boarding activities in the outer estuary. Motorized activity poses the largest threat because of the potential for fuel leaks, and because their noise and speed present a more extensive and intensive invasion and displacement of wildlife. The placement of an adventure, cultural or interpretive centre in the middle of the estuary would also present a large threat, by attracting large concentrations of people and their vehicles to the proximity of wildlife ‘hotspots’ and vulnerable areas. For example, the land title to Site A, held by First Nation, allows for the development of a cultural centre. Although it must abide by a conservation covenant, it would cause fragmentation and loss of an already rare, mature, estuarine fringe forest.

The District of Squamish, in conjunction with Forest Renewal BC, recently assessed the feasibility of a pedestrian crossing over the Squamish River to provide new recreation opportunities. Baumann Engineering (1998) suggested that a suspension bridge would be too costly, but that a cable car crossing would be feasible next to the BC Rail Yards (the crossing is easily identified by an outstanding rock outcrop on the western shore of the river). If such a crossing were developed, trails would undoubtedly run along the pipeline route, which intercepts the estuarine flats of the western delta. It would then be relatively easy to establish a trail network in these currently undisturbed mudflats and saltmarshes. There are no other known land use threats to the western portion of the estuary. Jim Tiampo donated 400 acres west of the Training Dyke, to the Squamish municipality in the fall of 2002. Signs, shelters and trails are allowed in Tiampo Park. Recreationists and tourists do access the western delta (mount of Monmouth Creek) by helicopter or canoe on occasion, but the usual destinations are high elevation lakes (Lovely Water, Echo and Henrietta Lakes) and peaks in the Tantalus Ranges.