The Fraser River Estuary (FRE) is the largest estuary on the Pacific coast of North America (Georgia Strait Alliance’s Biodiversity Program, 2020), and it is part of the most ecologically-important river-delta-estuary system on the west coast of Canada (Ramsar Sites Information Service [RSIS], 2012). The estuary plays a crucial role in food webs, as it links fish, birds, and marine mammals across thousands of kilometres of the North Pacific Ocean (Raincoast Conservation Foundation, 2021). 

Pre-contact First Nations in the FRE lived in permanent communities sustained and nourished by the abundance of the sea, rivers, and forests in this territory rich in natural resources (Fraser Basin Council [FBC], 2013). Culturally-significant foods and medicinal plants were plentiful and sustained local communities through seasonal hunting and gathering. Salmon fishing in particular has a strong place-based cultural significance, with people returning to the same spot, even rock, on the Fraser River throughout generations to dipnet for salmon (Indigenous Tourism British Columbia, 2019). Some First Nations take part in the first salmon of the season in ceremony with their community. The practice of gathering and managing seasonal food and medicinal plants  was performed in a manner that ensured long-lasting abundance in order to support the health and well-being of families and the greater community (FBC, 2013; First Nations Health Authority [FNHA], 2022). 

Oral history suggests that contact between First Nations and non-Indigneous people, traders and explorers occurred in what is now known as the province of British Columbia (BC) in the late 1700s. Diseases brought by non-Indigenous people were unlike any First Nations had ever encountered and devastated the Indigenous population estimated in pre-contact BC to range from 200,000 to more than one million (FNHA, 2022). With mortality rates in some villages ranging upwards of 50% to 90%, First Nations communities were weakened by disease and population collapse, thereby becoming more susceptible and vulnerable to the programs and policies imposed by colonial governments and churches that targeted and affected the Indigenous land, resources, education, health care systems, and more (FNHA, 2022). 

Hunting and gathering for cultural and sustenance purposes have been made increasingly difficult post-contact due to the significant loss of land, over-acquisition of resources, and property restrictions imposed by non-Indigenous people. Colonization has greatly contributed to habitat and species loss through dramatic changes to the landscape (FBC, 2013). Many modern-day settlements were initially built and currently rest in areas of high biodiversity (UBC, 2020). This includes the FRE, which is now a highly urbanized coastal region and houses 102 species that are at risk of local extinction (Kehoe, et al., 2021). 

Regional Description

The FRE is home to over 30 nations, including the traditional territory of the Coast Salish, sq̓əc̓iy̓aɁɬ təməxʷ (Katzie First Nation), šxʷməθkʷəy̓əmaɁɬ təməxʷ (Musqueam), sc̓əwaθenaɁɬ təməxʷ (Tsawwassen First Nation), S’ólh Téméxw (Stó:lō Nation), Á,LEṈENEȻ ȽTE (W̱SÁNEĆ Territory), Kwantlen First Nation, Stz’uminus First Nation, Qayqayt First Nation, Semiahmoo, and the Hul’qumi’num Treaty Group (Native Land, 2021). Many of these Nations have ongoing initiatives and efforts fighting to protect places, such as the FRE, from further habitat loss and ecosystem degradation that has occurred through post-contact land-use and development.

The majority of the FRE lies within the regional district of Metro Vancouver, which is part of the larger Lower Mainland region in BC. The FRE covers 1,072 km² of terrestrial land (Kehoe, et al., 2021), including areas within the municipalities of Richmond, Vancouver, Burnaby, New Westminster, Surrey, White Rock, Coquitlam, Port Coquitlam, Maple Ridge, Langley, and Delta (Province of British Columbia, n.d.). The surrounding marine areas of the estuary include the Strait of Georgia to the west, Boundary Bay to the south, and the Fraser River running through the centre. The Fraser River is BC’s longest river travelling 1,375 km, and with its tributaries drains approximately one-quarter of BC in a combined 240,000 km² watershed (FBC, 2022). 

In the Lower Mainland, nearly every community is vulnerable to the direct or indirect impacts of flooding from the Fraser River and/or coastal waters, particularly those in low-lying areas and bordering the river. This region was once a vast floodplain, and the eastern portion of the Lower Fraser Valley (Finn, et al., 2021), in the traditional lands of the Semá:th people, previously contained Semá:th Lake or Sumas Lake (Sumas First Nation, 2022). Pre-contact Sumas Lake was a freshwater lake up to 212 km² in size, surrounded by wetlands that supported fish, birds, and mammals (Bricklight Films, ​2021), as well as several villages, estimated with up to 10,000 people (Gomez, 2021). Sumas Lake was drained by pumps in 1924 for agricultural use of the fertile land beneath it, and the area is maintained as land by preventing the lake from re-forming through a series of dikes, canals, and pumps (Finn, et al., 2021). Pumping stations pump water into the Sumas River that eventually joins the Fraser River (Olsen, 2021). 

The region of the FRE ecosystem (also known as the Fraser River Delta), where the river meets the Pacific Ocean (Nature Conservancy Canada, [NCC], n.d.) is highly susceptible to flooding. This flooding-vulnerable region includes Sumas Prairie, particularly the previous location of Sumas Lake, with the button of the lake bed lying approximately at sea level (Olsen, 2021). The Municipality of Delta projected a 1.2 m sea-level rise over the next 100 years (Barron, et al., 2012). In November 2021, a series of atmospheric rivers caused the Fraser River and Nooksack River to swell, water from the Fraser River threatened the pump stations that if failed would cause Sumas Lake to re-form (Insurance Bureau of Canada [IBC], 2021; Olsen, 2021). Although the lake did not fully reform, substantial flooding occurred, resulting in the most expensive severe weather event in BC’s history, with an estimated cost of $450 million in insured damage (Insurance Bureau of Canada, 2021).

The FRE is within BC’s Coastal Douglas-Fir Biogeoclimatic Zone (CDF zone), which is largely a coastal region of temperate rainforests that primarily consists of mountainous terrain, excluding the Fraser Valley floor and Fraser River Delta regions’ lowlands (NCC, n.d.). The CDF zone is the most altered by humans of all other zones in BC, with 49% of the land base occupied by human activity, with wetland ecosystems within the CDF zone at a 75% loss of its former area (Coastal-Douglas Fir Conservation Partnerships [CDFCP], 2022). The CDF zone is one of the warmest ecoregions in Canada with the mean average annual temperature of approximately 9°C (15°C in the summer and 3.5°C in the winter) and a mean annual precipitation ranging between 850 and 2,000 millimetres (NCC, n.d.). 

The FRE contains five provincially designated Wildlife Management Areas (WMA), including Sturgeon Bank, Roberts Bank, South Arm Marshes, Boundary Bay, and Serpentine WMA (Vancouver Aquarium, 2018). Collectively, these areas cover approximately 20,700 ha and encompass estuarine marshes, open water marine habitats, mudflats, floodplains, sloughs and river channels (RSIS, 2012; City of Delta, n.d.). The WMA conservation areas provide critical habitats for communities of vegetation, migrating and wintering waterfowl populations, and fish and marine mammal species (Province of British Columbia, n.d.). The Fraser River Delta is also home to Burns Bog, which is a 3,000-ha area of the Fraser River delta and the largest raised bog ecosystem on the west coast of North and South America, as well as the largest undeveloped urban landmass in North America. Currently, 2,042 ha of Burns Bog is protected as an Ecological Conservancy Area (City of Delta, n.d.). These conservation areas amount to approximately 9% of the FRE is protected conservation areas, with less than 1% of the CDF zone remaining in old-growth forests (CDFCP, 2022). 

The Fraser River contributes approximately 44% of freshwater from its watershed into the Salish Sea, the combined waters of the Strait of Georgia, Puget Sound, and the Strait of Juan de Fuca (Encyclopedia of Puget Sound, 2015; MEOPAR, 2021), and deposits approximately 12,700,000 m³ of sediment and 450,000 tonnes of organic matter annually into the shallow sand, intertidal marshes, and mudflats of the estuary (Balke, 2017). Organic matter deposits from the Fraser River support substantial populations of invertebrates, which are consumed by birds such as great blue herons (Ardea herodias) and bald eagles (Haliaeetus leucocephalus), fish such as juvenile salmon, and other wildlife (Balke, 2017). Sediment deposits build up and raise marsh platforms, such as Sturgeon Bank, allowing them to persist as sea levels rise (Maxwell, 2021); however, the construction of man-made dikes and jetties has disrupted this process by displacing sediment and significantly impacting the habitats and movement of fish and other wildlife (Gamage, 2021). For example, the diking infrastructure that is required to keep Sumas Lake from reforming fragments the Lower Fraser River fish habitats, disconnecting them from approximately 85% of their historical floodplain fish habitat (Finn et al., 2021). Some estimates claim that 90% of wetlands that could have served as viable fish habitat in the Lower Fraser have been lost (Finn, et al., 2021). 

Designated as an important bird and biodiversity area there are over 250 species of birds observed in the FRE in a given year, including migratory shorebirds such as the Western Sandpiper (Calidris mauri). Over 1 million Western Sandpiper utilize the FRE and Roberts Bank mudflats during the spring migration as their last stop on route to the arctic. Migratory birds including the Western Sandpiper feed on the biofilm, a rich diatom soup that covers the mudflats and provides migratory birds with the essential omega-3 fatty acids that fuels their next migration to the arctic (RSIS, 2012; Balke, 2017; (Government of Canada [GOV], 2018). The estuary also provides a migration route for salmon runs. The salmon feed on the diatoms providing them with the fatty acids that fuel their migration (GOV, 2018), through the Fraser River and its estuaries. The Fraser River is the world’s largest free-flowing salmon river. It is used by all five species of Pacific salmon and salmonids to reach their spawning grounds, and supports over 50% of BC’s salmon (Lessa, 2020; Balke, 2017). This estuary is an extensive food web for marine mammals, notably the southern resident killer whales (one of Canada’s most endangered marine mammals), which has a diet composed of 80% Chinook salmon, a species that migrates through this estuary (David Suzuki Foundation, 2021; Georgia Strait Alliance’s Biodiversity Program, 2020). 

Delta’s economy in particular is strongly supported by agriculture and fishing (City of Delta, n.d.). The fisheries and aquaculture sector contributed $1.0 billion to the province’s economy in 2016, or 0.5% of total real gross domestic product (GDP) for the province, despite salmon facing a severe decline falling over 92% since 1990 (Sun & Hallin, 2018). In 2016, within the larger region of Metro Vancouver and the FRE, the total farm area was 38,380 ha. While only occupying 1.5% of the province’s agricultural land, this rich farmland generates over $945 million or 26% of the BC’s gross annual farm receipts (Metro Vancouver, 2017). As of 2016, the number of farms using irrigation in the Metro Vancouver region was upwards of 34%; in Delta, 54% of farms used irrigation on their crops (Metro Vancouver, 2017). Rising temperatures due to climate change are the likely reason for an increased demand for irrigation and the availability of freshwater. From 2011 to 2016 alone the overall number of farms using irrigation across Metro Vancouver increased 11% (Metro Vancouver, 2017). 

Potential and existing disruptions to regional water security

Municipalities and other inhabited spaces in low-lying and floodplain areas within the FRE, such as Delta and Sumas Prairie, are highly vulnerable to river and coastal flooding and the associated water-related hazards that are expected to occur, particularly sea-level rise from climate change. Additional water challenges include saltwater intrusion from sea-level rise and its significant impacts on local public health, the economy, well-being, and the environment (FBC, 2016). Flooding and urbanization are known as both existing and potential impacts on the critical habitats of the FRE ecosystems (Kehoe, et al., 2021). 

Since European colonization, humans have heavily modified the FRE through agricultural, industrial, and urban development (Balke, 2017). In Delta alone, approximately 8,600 hectares or 90% of Delta’s farmland lies within the Sea Level Rise planning area (Barron, et al., 2012). Currently, one of BC Ferries’ major ferry terminals operates in this estuary, as well as a coal port and container ship facility on southern Roberts Bank (Western Hemisphere Shorebird Reserve Network [WHSRN], 2019). While the outer brackish wetlands and salt marshes remain somewhat intact, nearly all the seasonal wet meadows, bogs, and floodplain forests throughout the delta have been converted through human land use (Balke, 2017). Jetties and dikes built to protect hundreds of thousands of British Columbians homes and expand agriculture now impede the natural migration of ecological zones shoreward as sea levels rise, squeezing these zones against the dikes (WHSRN, 2019; Balke, 2017).

Canada’s Marine Coasts in a Changing Climate report concludes that the loss of habitats in areas like the Fraser River Delta are attributed to coastal squeeze, where structures like dikes block the inland migration of the marsh vegetation zones and marshes drown due to the prevention of natural drainage (Lemmen et al., 2016). Lemmen et al. (2016) report that according to the Intergovernmental Panel on Climate Change’s (IPCC) 2001 projections of sea-level rise, the central Fraser River delta front marsh losses could amount to 15% to 35% and approximately 70% of these losses could be attributable to the presence of dikes. Pollution from urban areas is also impacting the estuary, leaving it with one of the worst environmental health rankings, as per the Pacific Estuary Conservation Program (PECP) Estuary Ranking Report (PECP, 2019). 

Sea-level rise is a particularly significant threat to the Fraser River Delta ecosystem, with 2,200 ha of riparian habitat, 9,500 ha of intertidal habitat and all of Burns Bog within the Sea Level Rise planning area (Barron, et al., 2012). ​Over a hundred species of fish and birds are at risk of extinction in the estuary, including the White and Green Sturgeon (respectively, Acipenser transmontanus and Acipenser medirostris), and the Eulachon (Thaleichthys pacificus) (RSIS, 2012; Georgia Strait Alliance’s Biodiversity Program, 2020). It is estimated that without implementing new effective conservation measures, two-thirds of the species within the Fraser River estuary have less than a 50% survival rate over the next 25 years (Kehoe, et al., 2021).

Sea-level rise and storm surges induced by climate change will have major impacts on human well-being, as increases in soil salinity resulting from ocean flooding and saltwater infiltration will impact crops and increasing scarcity of freshwater resources for irrigation will exert pressure on agricultural capacity and the farming population (Barron, et al., 2012). The Lower Mainland Flood Management Strategy, Phase 1 Summary Report, released by the Fraser Basin Council in 2016 estimates the total costs of a present-day river flood in the Lower Mainland to amount to 22.9 billion CAD, due to significant damages to residential, commercial, industrial, and public/institutional buildings, as well as interrupted cargo shipments, infrastructure losses and agricultural losses (FBC, 2016). A river flooding scenario projection for the Lower Mainland in the year 2100 estimates costs of damages to amount to upwards of 32.7 billion CAD (FBC, 2016). 

Current initiatives and efforts

Ducks Unlimited restores and manages wetlands and grasslands to benefit waterfowl, wildlife and people. Their goal is to ensure abundant wetlands and waterfowl for generations to come while improving Canadian lives. The organization uses and brings together multiple approaches to conserve wetlands and other natural habitats across North America efficiently and effectively.

Lower Fraser Fisheries Alliance comprises 30 First Nation communities with the mission of supporting the management of a robust and expanding fishery of the Lower Fraser River. The Alliance  works collaboratively and holistically to manage their fishery and support cultural and spiritual traditions for future generations.

Lower Fraser River Salmon Conservation Program was initiated by the Raincoast Conservation Foundation, and it focuses on research and restoration projects, with the goal of seeing healthy populations of wild salmon return to the Lower Fraser River. Previous projects of the Foundation include the Habitat restoration: Fraser River Connectivity Project that began in 2016 and has been the largest connectivity restoration project in the FRE in decades. This project created openings/breaches in several man-made barriers built to control the arms of the river for ship navigation. The barriers prevented the natural migration of juvenile salmon to the sea, particularly from entering the brackish sand and mudflat areas necessary for acclimation before entering the saltwater environment. 

The Sturgeon Bank Sediment Enhancement Pilot Project is being conducted in partnership with Ducks Unlimited Canada (Project Lead), Raincoast Conservation Foundation, Lower Fraser Fisheries Alliance, and Tsawwassen First Nation, and it aims to test, refine, and evaluate an innovative method of restoring tidal marsh. This project simultaneously supports ecological resilience for key species Fraser River salmon, steelhead trout, white sturgeon, and protects communities from coastal flooding. The project timeline is set for 2021-2024.

Pacific Estuary Conservation Program (PECP) is a program of the Pacific Birds Habitat Joint Venture (PBHJV) with an aim to coordinate efforts to secure and enhance estuary habitats with high ecological value along the BC coast. The PECP partnership consists of Environment and Climate Change Canada (Canadian Wildlife Service), Ducks Unlimited Canada, BC Ministry of Forests, Lands, Natural Resource Operations and Rural Development, BC Ministry of Environment and Climate Change Strategy, the Habitat Conservation Trust Foundation, the Nature Conservancy of Canada, and the Nature Trust of British Columbia. 

Pacific Salmon Foundation, in collaboration with the Fraser Basin Council, launched Salmon-Safe BC in 2011. Salmon-Safe BC is Canada’s only eco-certification program that links watershed considerations/conservation with land management practices, and it does this by encouraging farmers to use agricultural practices that protect Pacific salmon habitat and water quality. The program is supported with investments by the Province of British Columbia through the B.C. Living Rivers Trust, Fisheries and Oceans Canada and the Pacific Salmon Endowment Fund.

Watershed Watch Salmon Society is a science-based charity working to defend and rebuild B.C.’s wild salmon. Offering scientific expertise to policymakers, and highlighting the large scale issues affecting local waterways, from fish farms to climate change.

FUTURE OUTLOOK

Local Imperatives

The Lower Mainland is vulnerable to the direct and/or indirect impacts of Fraser River and/or coastal flooding as a result of climate change, the following are examples of major water-related issues identified by the region: 

• Ecological losses as a result of river and/or coastal flooding:
  • Habitat and species loss
  • Disturbance of food web interactions
  • Estuary stop-over disturbance for migratory birds 
  • Human interaction/urbanization altering sediment deposition 
  • Disruption of habitats and movement of fish and wildlife 
• Economic losses as a result of river and/or coastal flooding impact the following:
  • Agriculture, buildings, equipment and lost farm gate sales  
  • Residential, Commercial, Industrial, and Public/Institutional Buildings
  • Infrastructure, including hospitals, electrical substations, marine facilities, rail lines, wastewater treatment plants etc.
  • Interrupted Cargo Shipments

• Salinity issues as a result of river and/or coastal flooding impact the following:
  • Agricultural operations, irrigation, livestock 
  • Saltwater ingress (aquifers), impacting drinking water
  • Saltwater and freshwater balance of the estuary ecosystems

Future priorities and plans

Lower Mainland Flood Management Strategy (LMFMS) is aimed at reducing flood risk and improving the flood resilience of communities along BC’s lower Fraser River and south coast. There are three phases to the strategy developed by the Fraser Basin Council. Phase 1 (2014-2016) included an analysis of Lower Mainland flood scenarios, a regional assessment of flood vulnerabilities, and a review of current flood protection works and practices. Phase 2 (2017-2021/2022) aimed at developing a regional strategy to reduce flood risk and increase the flood resilience of communities along the lower Fraser and South Coast. Phase 3 is focused on the implementation of the Strategy (2022-).

Delta-RAC Sea Level Rise Adaptation Visioning Study Policy Report

Four Adaptation Scenarios are presented in response to hypothetical conditions of 1.2 m rising sea-level assumed to be in place by the year 2100:

• Scenario 1: Hold the Line
  Armouring scenario where existing dike and seawall infrastructure is maintained, raised and strengthened. This would leave no net gain or loss of land with the exception of Westham Island.
• Scenario 2: Reinforce and Reclaim
  Variation of ‘Hold the Line’ but with an addition of outer dikes built to close off some areas from the river/sea reducing incoming wave energy off-shore, allowing for slightly lower dikes or seawalls.
• Scenario 3: Managed Retreat
  Leaves existing dike and seawall infrastructure as is and only reinforces and maintains existing infrastructure to project major population concentrations and assets. Development in unprotected areas would be gradually relocated to higher ground.
• Scenario 4: Build Up
  Leaves existing dike and seawall infrastructure, raising infrastructure including roads, hospitals, schools and fire halls, new residential development would be built higher Flood Construction Levels and older residences would be gradually raised.