BC's Lower Mainland Prepares for Future Flooding
Vancouver International Airport and the Fraser River
Passengers arriving at the Vancouver International Airport are greeted with sprawling views of the Pacific Ocean as they descend onto Sea Island in Richmond, British Columbia. However, this serene proximity to the ocean raises concerns about coastal flooding in the wake of climate change.
The airport sits on low-lying land in the Fraser River estuary where it's susceptible to storm surges and sea-level rise over time, as described in the 2016 Climate Risks and Adaptation Practices for the Canadian Transportation Sector report, part of the national Canada in a Changing Climate assessment. The Government of Canada is currently updating Canada in a Changing Climate, the next national assessment of how Canada's climate is changing, the impacts of these changes and how we are adapting to reduce risk.
Exposed to floods
B.C. highway damaged by flooding
A recent report by the Fraser Basin Council (FBC), a non-governmental organization, suggests that without investments in planning and infrastructure improvements, surging seas could swamp Canada's second busiest airport and surrounding vital assets.
Climate change also exposes British Columbia's lower mainland to springtime flooding of the Fraser River. Higher temperatures would accelerate snowmelt and spring rains would add to river flows, leading to more flooding events. While the region is protected by 500 km of dikes, a 2015 assessment found that most would be vulnerable to failure during a major flood. Nearly all were built 30 to 50 years ago when different standards were in place.
A regional issue
The city of Richmond is particularly vulnerable to major flooding events as it lies entirely within a flood plain. The same is true for Vancouver's lower-lying edges and other nearby communities in the region. Indeed, many First Nations reserves and treaty lands in the lower mainland have no dike protection at all.
The Lower Mainland Flood Management Strategy Report (2016) prepared by FBC estimates losses of $19 to $23 billion if a major coastal or river flood happened today, and considerably more if they were to occur in 2100, due to larger and more sweeping floods. The report tallied essential facilities, including hospitals, fire halls, police stations and transportation services that would be damaged, destroyed or unable to function. More than 200,000 people could be displaced.
The airport is adapting
For the Vancouver International Airport, these hazards are not unfamiliar. The Vancouver Airport Authority, which is a partner in the Lower Mainland Flood Management Strategy, is well aware of the risks that climate change poses to the greater Vancouver community, says Marion Town, the organization’s director of environment.
The airport boasts a comprehensive diking, stormwater management and flood box pumping system that spans across Sea Island. In an effort to safeguard against major floods of the future, it has invested significant resources into a multi-year program to raise dikes to 4.7m above mean sea level.
The airport authority is also working with Environment and Climate Change Canada on dike improvements within the federally owned Sea Island Conservation Area lands on the north side of the island. Moreover, it has established a plan to protect critical infrastructure within buildings, some parts of which lie below sea level.
Patullo and railway bridges in North Surrey, B.C.
Elsewhere, the City of Vancouver partnered with multiple stakeholders to commission a two-part Coastal Flood Risk Assessment that identified flood hazards, vulnerabilities, and consequences expected over the next century, which led to a new floodplain map with updated flood construction levels. In addition, Metro Vancouver has factored climate change, heavy rain, snowmelt events, and sea level rise into its Liquid Waste Management Plan, which is aimed at protecting public health and maintaining a healthy environment.
Partnerships are key
Finding solutions to the issue of rising waters requires collaboration on a regional scale of all orders of government, says Steve Litke, FBC’s senior program manager, watersheds and water resources, "No one municipality could handle this on their own." Partners in the strategy include municipal, provincial and federal governments; First Nations; the transportation sector; academic organizations; and other private sector and civil society organizations.
"The work that went into the FBC report improved our collective knowledge and is very helpful to strengthen and develop partnerships and raise awareness of the problem," he explains. "This is a significant issue – but not all doom and gloom."
Considerations for the future
Some construction considerations remain. To ensure their structural integrity, dikes need to be widened in order to raise them. There could be environmental impacts if dikes were extended into the Fraser River.
Solutions being discussed include careful land-use planning, dike repairs and relocation, wetland restoration, as well as investing in "living dikes" and shorelines (see Spotlight on Innovation). For example, The Nature Conservancy in the United States is experimenting with building oyster reefs in the Gulf of Mexico that would act like small barrier islands to reduce the impacts of storm surges. In British Columbia, this tactic might work in places like Boundary Bay, once a productive oyster harvesting area.
"We have to consider what makes sense for different local conditions," says Litke, who recommends a well-researched and cautious approach. "We need to have some humility when working with large rivers."
"Soft" solutions such as greening shorelines and building "living reefs" might prove to be effective in some situations and may cost less.
Greening Shorelines to Enhance Resilience, a 2014 report prepared by SNC-Lavalin for the Stewardship Centre for British Columbia, compared the viability and costs of soft shore versus hard shore "armouring" techniques. Not only were the soft shore methods, such as beach nourishment, berms and rocky reefs better for the environment, in some circumstances they were less expensive than traditional techniques including hard armouring and seawalls.
The report's findings were based on case studies of three shoreline properties where future flooding is predicted. The locations were Qualicum Beach, the West Vancouver shoreline, and a residential property on Vancouver Island.
Funding for the study was provided by Natural Resources Canada.
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