This is The ChangeUnderground for the 26th of July 2021.
I’m your host, Jon Moore
Decarbonise the Air, Recarbonise the Soil!
If there is a rule of thumb with flood defences it is this: any levee will be overwhelmed by a flood no one expected.
With the floods in Germany, Belgium and the Netherlands during the last week questions will be asked. Things like: Why weren’t people warned earlier? Why wasn’t this planned for? Is this really related to climate change?
And these are all relevant and necessary questions. But they miss, from where I sit, the principle question: Why are floods appearing to increase in levels?
We had floods here too in Australia back in February, I think. One of Mrs ChangeUnderground’s sons had just moved into a house on the Hawkesbury River. When I say just moved in, I mean a fortnight earlier.
And in the last couple of days before writing this episode, China has been hit with floods. Now floods in China are part of the Chinese reality. Millennia of flood defences have failed spectacularly from time to time.
Where we lived in Ireland for a few months, Skibberrean, flood levees were in the process of being built.
What do all these floods have in common?
They rely on actions at or close to the areas of flooding. Obviously that’s where the danger is. The rainfall causing floods though, tends to fall upstream, obviously. This links in nicely with last week’s episode. Into The Forest, episode 264. Trees do more than contain carbon, it’s great that they do that, clearly, but they also slow floodwaters. All waters actually. A key feature of forests is their soil. These build over time, either evergreen or deciduous. They become sponges. This is especially important on sloping country and the further we travel up the watershed.
The conclusion reached last week that increases in human population equals falling tree cover points to the problems short term flood defences create. As urban areas expand, farming areas push further up watersheds, looking for land to produce food. To produce food, trees are felled. As more and more of the watershed is cleared for agriculture and this agriculture was/is predominately based upon tillage and fallows, and rain dumps topsoil into the waterways. This makes them shallower over time and also increases the risk of flooding. Eventually we reach a point where 80% or so of the initial tree cover is gone, waterways are shallower and the big rain event arrives.
In the past levees were built for say 1 in a hundred year floods. Those floods are now more likely because the water cannot be sponged up by the forests nor flow through the no longer as deep catchment and so rivers, streams and creek burst their banks and overwhelm flood defences of all kinds.
In the case of the Hawkesbury this year and the Brisbane floods of 2011, a major water supply dam in the upper reaches of the river systems was supposed to act as a brake on the water flow. The dam fills, the waters are let out of the dam at slower rates than their ingress and the peaks of the floods are lowered.
This is the same deal sold to the Chinese people with the Three Gorges Dam. I’m not sure about the current Chinese floods but in the Brisbane and Hawkesbury floods, the dams filled so quickly they failed to slow the rate of flooding and sluice gates had to be opened to stop the dams failing catastrophically.
Even a cursory search will reveal the land clearing, as it’s called when it should be called, tree cover removal, continued apace before and after the dams were built. Not sure about the Brisbane dams but there are moves afoot to raise the Warragamba Dam to “protect” the Hawkesbury. This is the same as raising the levees.
None of this will make a blind bit of difference until the catchment areas are reforested. The obviousness of this, to me anyway, is beyond question. Yet one of the consequences of our Pleistocene minds and bodies living in the Anthropocene as discussed in episode 263 is our tendency to face what is immediately before us and not what may be the cause of what’s before us.
[I can feel a supplementary series of episodes on this in the near future.]
This means we focus on the flooded areas and not the upstream causes of the flood. With increasing global temperature, 1 degree equally 6% more moisture, and I can’t find the reference for this figure, I heard it on a podcast this week so if any of you can find the link I’d appreciate you posting it in The ChangeUnderground Podcast Group on FaceBook, thanks. But increasing temperatures bringing increased moisture can only point to more flood events. To solve two problems with one action, reforesting the upper catchments and contour planting hedgerows on agricultural land seem a no brainer. Saving what remains of our forests is critical too. So I’ve relisted the link to last week’s petition to protect Ancient Forests in the Uk. It turns out anyone in the world can sign, so let’s flood that petition with our names. (See what I did there?)
In related news which can only point to more variations in the future comes an article from the Australian edition of The Guardian entitled: Amazon rainforest now emitting more CO2 than it absorbs. So that’s all good then. I’m surprised at the lack of concern over this news and I’ll have more to say next week but for today’s episode, it seems more common flooding rains are in our immediate future.
What’s to be done? It sounds like a broken record but plant more trees, rotate stock regeneratively and grow the no-dig way.
So If you’d like to start your gardening adventure and life time of astonishing insights go to the website: https://worldorganicnews.com/freeebook/ and you can obtain a free copy of the eBook outlining The ChangeUnderground No-Dig Gardening System.
If you have any questions, thoughts or suggestions, I opened a Facebook group. I’ve called it, imaginatively, ChangeUnderground Podcast Group. You can search on the Book of Faces or there’s a link in the show notes and in the transcript over at WorldOrganicNews.com/episode265.
Following the crash a month or so ago, I’m slowly adding the transcripts for the back catalog so thank you for your patience.
Decarbonise the air and Recarbonise the soil.
Thank you all for listening and I’ll be back next week.
The ChangeUnderground Academy No-Dig Gardening Course:
FREE eBook: https://worldorganicnews.com/freeebook/
Bubugo Conservation Trust
Amazon rainforest now emitting more CO2 than it absorbs
HS2 Petition to Save the Ancient Woodlands of England