Rivers, floods, and climate change

It’s spring. Sometimes known in northern reaches such as ours as mud season. To be clear, spring in these parts usually starts several weeks after March 21, after the winter’s snow has really left. And, if you live near a river in these northern climes, mud season comes after the nail-biting spring freshet. The spring freshet is the thaw that happens when the accumulated snow and ice in the river’s watershed melt and swell the river. The nail-biting part is from the anxiety caused by waiting to see if the thaw will be nice and gradual, aka benign, or rapid and dangerous, maybe even very dangerous.

In the past several years, rivers that historically produced destructive floods infrequently are starting to reach damaging flood levels entirely too often. The website floodlist.com does a good job of showing just how extensive flooding has become around the world. In eastern Canada this year, not just my home province of New Brunswick but also Ottawa and Montreal have recently declared states of emergency and have asked the armed forces to help combat the ravages of unprecedented flood levels. The question being asked now: is this the new normal?! And given the possibility of even one damaging flood, why do people want to live near a river?

Rivers

People live along rivers for many reasons, and have done so for thousands of years.

  • Rivers can be used for transportation. Many of the world’s cities and towns were established along rivers and at the mouths of major rivers for precisely this reason.
  • Rivers are nurturers of the agricultural land they pass through. In the good years, when the spring freshet is benign, the seasonal flooding – manageable and brief – replenishes the soil with nutrients carried in the flood water and deposited as the water recedes. This has been the case throughout history: with the Nile in Egypt, the Tigris and the Euphrates in the Fertile Crescent that is modern day Iraq, the Yellow River in China, and our own St. John River in New Brunswick in eastern Canada, to name a few.
  • Rivers can provide irrigation, fresh water, and food! They also provide a habitat for wildlife and vegetation.
  • Rivers feed the soul. They are one of nature’s many gifts, bestowing beauty and a sense of awe, sometimes awe at the peacefulness of the scene and sometimes at its raw power.

We live on the St. John River, a beautiful, life-affirming river that has provided nearly all of the above. I will digress a bit here to explain that the St. John River only became known as the St. John River when it was “discovered” by Samuel de Champlain on June 24, 1604, which happened to be the feast day of Saint John (who Champlain undoubtedly called Saint Jean, since he was French). For thousands of years, before a shipload of Europeans arrived on the east coast and happened upon the river, the river had been known as the Wolastoq, which means “the good and beautiful river”. The Maliseet people, who still live here, are known in their language as the Wolastoqiyik, or “people of the beautiful river”. If that doesn’t speak to how important the river has been to the people living along its banks since time immemorial then I don’t know what does.

St. John River features prominently in the map of New Brunswick

The St. John River, or the Wolastoq, has provided a habitat for fish (especially salmon!), deer, moose, bear, small mammals, eagles, osprey, and a wide variety of other birds. It has nurtured majestic softwood forests in its northern reaches and arable land further south. It provided transportation in the more navigable southern part of the river before the advent of trains and then motorized vehicles. It provides hydro power; its tributaries provided power to mills through waterwheels and then more modern technology. It has renewed the agricultural land yearly during the freshet. In earlier times the mighty St. John and its tributaries provided the transportation for massive log booms that wended their way down river from where the logs were cut in the forests to the mouth of the river, where the logs were either milled and made into ships or shipped directly to Europe for use there.

And, of course, all kinds of people through the centuries – the Wolastoqiyik, the French, the British, and then all of us together as Canadians – have chosen places along the river to live, both for these reasons mentioned and for its beauty.

Floods

We all know that rivers flood. As I’ve indicated, a little flood water passing over arable land is actually a blessing. Also, the ancient Egyptians are said to have waited for the floodwaters to come up so they could float the massive stones for the pyramids down the Nile. But sometimes the freshet turns from providing a bounty of renewal with minimal disruption to a destructive force of nature. It then brings far too much water to far too many places, causing enormous and heartbreaking destruction of property and infrastructure, dislocation, injury and even death to people and animals, and leaving fields too waterlogged to be planted.

What causes the spring freshet and what causes the freshet to turn from benign to destructive?

My running trail under lots of water

Rivers swell and flood each spring because of melting snow and ice. Ideally, the weather during the spring melt is what we think of in these parts as perfect maple syrup weather: warm sunny days (6-10C/40-50F) and cool nights (-2 to -7C/20-30F). You can have a very heavy snowpack in the woods from the winter accumulation, but if you get the right melting conditions, the melt will be slow and steady … and life is good. If the melt is too fast because of a sudden shift to much higher temperatures, say 20C/65-70F, then disaster may be right around the corner. If you get one or more (several) days of heavy rain – or if an ice jam develops – your goose is cooked. There is just too much water coming into the river system too fast and it’s just a question of how far above flood level the river is going to rise. So it’s a simple formula: A + T + P = R. Amount of snowpack in the river’s watershed + Temperatures in March and April + Precipitation amounts in March and April = River level during freshet. Sometimes you win and sometimes you lose; it just depends on the combination of those factors.

Downtown Fredericton at height of flood

That having been said, the vagaries of each river are known, and buildings, bridges, roadways, and fences are expected to be built to a responsible standard. For example, in 1973 our town experienced what was called at the time the flood of the century. In other words, the flood level far exceeded the average and would not be expected to recur for a very long time. One could also say that there would be about a 1% chance of having a flood that serious. We build to the 1973 flood level. But since 1973 we’ve had three years that have come extremely close to the 1973 level: 2008, 2018, and 2019. The 1% chance rule seems to have broken down.

The Bell Falls Dam in Quebec, on a tributary of the Ottawa River between Ottawa and Montreal, was upgraded in 1999 and this season has so much water going over it that it is in danger of failing. The current flow is 10 times the normal flow, which was only expected to happen once in a thousand years. Entirely unprecedented. Because of lots of extreme weather, we find ourselves operating with new flood rules after hundreds of years. The jury is out – for some people – on whether these are one-off extremes and whether the fact that it’s happening with increasing frequency is just a coincidence. I don’t think the jury will be out for long.

Climate change

We are now experiencing more extreme weather events right around the world. Much heavier rains. More violent storms. More freezes and thaws. Is this due to climate change or just random confluences of natural factors?

For sure, some additional runoff comes from increased development (cutting down trees to put up buildings and parking lots), and some flooding could be prevented by refusing permission for new structures to be built in flood plains. Certainly regulations for protection of wetlands could be tightened and enforced in more places. But the fact that there has been this much excess water in so many places in just a few years – in unprecedented amounts – has to make you wonder.

Climate change means more extreme weather, both hot and cold, including more violent storms in some places and more droughts in others. More extreme weather changes the game for the factors that define flood levels. It would be nice if the random/coincidence argument were to win out and these destructive and disruptive floods were to be shown to be one-offs, true once-in-a-century floods, just randomly happening several years running. Sadly, I’m not holding my breath.

The side of our house, Feb 27. The river is in the background, behind the final row of trees (covered with ice and snow).

Same location, April 23

Same location, April 23, after the ice floated in from upstream.

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9 Responses to Rivers, floods, and climate change

  1. barryh says:

    Yes there is a fatal fascination about rivers. Over the years we have travelled around most of France. I would say that pretty well all the interesting old towns sit on rivers (or by the sea). Before roads these were the travelling highways, or obstacles that needed to be crossed. So yes, so many places are vulnerable to the extreme weather that climate change IS NOW bringing.

    • Jane Fritz says:

      Yes, there are so many beautiful rivers throughout Europe and the UK. And it strikes me that there have been some frighteningly serious floods on some of those rivers relatively recently, including one in my favourite part of the UK, the Ouse.

  2. Roy McCarthy says:

    But it’s OK. Scotland, and today Jersey, have declared climate emergencies. Nice little vote winners. And, like Ireland, they’ll start missing their interim targets and will say ‘we did our best’. The truth is that no one wants to be inconvenienced on a personal level and so it will go on.

  3. Reblogged this on Musings and Wonderings and commented:
    Ah yes the joys of seasonal fluctuations enhanced by climate change– welcome to unprecedented change!

    • Jane Fritz says:

      Sadly, yes. My son’s family in Ottawa has now had a porta-potty places at the end of their driveway because the sewer system in the west end has been compromised by the unprecedented volume of water flowing through the Ottawa River. No flushing now allowed in that neighbourhood! Thanks, climate change.

  4. How are things at you house now?
    Same changes and problems this side of Canada only add in forest fires. Seems we are all now living in the 1% chance…..

    • Jane Fritz says:

      I’m happy to say that the water is slowly – very slowly – receding, leaving lots of crap in its wake. But it hasn’t even started to recede further down river. It’s something to be on the receiving end of both drought and flood extremes at the same time. BC enjoys such extraordinary beauty and majesty in its landscapes, it doesn’t seem fair to be hit by that double whammy. Scotland is also suffering from terrible forest fires at the moment. Extremes, extremes, extremes.

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