Article content The mighty Fraser River lies at the heart of B.C. It is the province’s longest river, rising in the Rocky Mountains and flowing 1,375 kilometres before entering the Pacific Ocean at Vancouver.
Its drainage basin is the size of Britain. Its salmon migrations are key elements of Indigenous culture and B.C.
’s commercial fishery. The Fraser Delta houses Canada’s largest port facility. The river is unassailably large, free-flowing without dams on the main stem, and powerful.
We are reminded of the Fraser’s power during the annual spring floods that routinely sends 10,000 cubic metres of water per second through the most densely populated part of Western Canada. Residents of smaller communities built along the river live in awe of the river’s power and fear that it will wash them away in a flood. In larger communities, flood defences allow us to forget that one of the most powerful mountain rivers in the world debouches into the ocean in our backyard.
Yet the river is also fragile in ways we might not expect. When people think about protecting the Fraser River, they often think of protecting the birds living on the delta mud flats, salmon who use the river as a superhighway to get to their spawning grounds, and the rich diversity of plants and animals that live along the river. It is rarer that people think of what makes up the habitat of these plants and animals.
It is sediment, chunks of rock broken away from canyon walls, crushed by glaciers, and worn round by the river. There is a problem with sediment in the Fraser River; there is not enough to go around. Great plumes of silt and clay are carried through the river, but that is not what makes up the river.
Rivers are authors of their own geometry — the bottom and banks are made up of gravel and sand that the river has carried and worn down over millennia, not the silts and clays that wash into the ocean each year or sit on top of floodplains. The amount of sediment delivered to the Fraser Delta has declined by 50 per cent in the past 50 years. Dredging to allow safe travel of ships has created an upstream wave of erosion, incising the river from New Westminster to Mission and every year more erosion occurs.
The sand currently delivered to the delta is much less than is dredged to maintain the shipping channel in the Fraser. This results in a deficit of sand in the Fraser Delta; the sand that built the river channel and delta are gradually being eroded. That poses a big problem.
The sediment deficit means erosion will undermine the stability of the delta channels. Don’t panic though. Engineers can stop the erosion, protect us from floods, and even engineer elements of fish, bird, and plant habitat that we deem important enough to save.
But that belies a more complex problem. At present, the Fraser River is relatively natural. Compare the Fraser to other places in the world with major cites on deltas and you’ll see a stark contrast.
Did you know that New York City was built on a delta? Compare the Port of Vancouver to Europe’s biggest port: the Port of Rotterdam. What you’ll find is that these deltas are anything but natural. They are concrete channels where the inherent natural beauty and biodiversity have been almost entirely lost.
The situation may seem dire, but it is not. There are two things we can do. First, we can ask ourselves what kind of river we want in our backyard and start working toward a goal.
Environmental activists often think that we should have no environmental impact, but more realistically there are trade-offs to be made. If we want a major port and all the wonderful things it brings to our shores, we must accept some engineering of our river and coast. If we are going to live along a powerful free-flowing mountain river like the Fraser, then we need flood defences.
What kind of Fraser River do we want? If we do not answer this question, engineers will gradually and incrementally convert the Fraser to something different from what it is now, and we may not even recognize the changes for decades. The second thing we can do is start monitoring the river to collect baseline scientific data. It is surprising that the most important river in B.
C. is almost entirely unmonitored. How can we know the combined impacts of climate change, urbanization, industrialization, and land-use change if we don’t know the baseline? On Nov.
1, 2018, a small rockfall occurred in a canyon near Big Bar, which reminded us how interconnected we all are with the river. The rockfall blocked the Fraser River to upstream salmon migration, threatening the northern basin’s salmon runs. Just six weeks ago, another landslide occurred on the Chilcotin River, a major tributary to the Fraser.
These landslides came as surprises, but there is no reason why they should have been. I led a team funded by the B.C.
Salmon Restoration and Innovation Fund to look for future river-blocking landslides and we identified 13 sites of concern where we think another river-blocking landslide is possible on the main-stem Fraser. For three years, our team watched for landslides in the Fraser River, but our work ended in March 2024, and now no one is watching. The next landslide will once again be a surprise.
The river needs a science monitoring centre. Most major rivers as important as the Fraser have a monitoring centre tasked with generating the data required to make significant management decisions and to feed data to emergency responders. Yet in B.
C. this does not exist. Instead, we have a patchwork of government agencies, NGOs, consulting companies, and university researchers all struggling to put the pieces together, and all plagued by an absence of baseline information on the state of the river.
We need a science monitoring centre to archive past information and provide baseline data on the river so that we can detect change. We need an organization tasked with watching for the next landslide, measuring the impact of dredging and climate change, and studying the fragility of the mighty Fraser River. The Fraser needs us to start watching, now.
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