After the flood

Almost two years ago, on Boxing Day 2015, there was severe flooding across the North of England. Particularly affected were Cumbria, where families had to be rescued from their homes by boat, and Lancashire, where most of my family lives. They live in and around the Rossendale Valley, through which the River Irwell passes on its way south to Manchester. On that fateful day, the Irwell was running dangerously high, due to vast quantities of rainfall both falling from the skies and running off the hills.

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Building barricades in Edenfield

I was staying with my dad, about halfway up the side of the valley, in Edenfield. As rain poured down on Boxing day, water gushed down the (recently resurfaced) track from the top of the hill and was in danger of going straight into numerous homes. Along with all the  neighbours we could extract from their Christmas festivities, we built a number of barricades to stem the flow. In some ways the experience was very rewarding, with the whole community pitching in to try and help their neighbours. Kids used brushes to sweep excess water into drains, whilst pensioners made cups of tea and homeowners supplied pieces of wood, stone and tarpaulin to build up the blockades.

After a few hours of dam building, we were successful in saving the nearby homes from any flooding. However, an ominous marker for people living in the bottom of the valley was presented by the sheer volume of water gushing downhill following one of our diversions, after the rain had stopped.

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Groundwater seepage

The rain had actually stopped pouring for most of the afternoon. However, groundwater continued to rush out and down the hillsides and into the river, to the point where its outward approach along my grandma’s street, near the valley bottom, was visible in real time.

The council arrived in Irwell Vale to deliver what looked a little like red sand bags, but which were instead filled with chemicals which would absorb water rather than just block it. Each house was given half a dozen of these, apparently at a great financial cost to the council.

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My grandma’s house after the clear-out job

As the flood waters rose, families either fled, were saved by boat or left trapped upstairs, as water levels rose to 3 feet or so. My grandma’s dog still hasn’t recovered from the experience of being trapped upstairs and seems somewhat traumatised by the event.

Flood waters receded again and left a truly awful state, with most furniture in need of removal, including a sad christmas tree. I came down to help with this clear out effort and found the expensive red bags provided by the council scattered around the garden almost uselessly. A few of them can be seen in the foreground of the photo opposite.

Why did the water raise so much higher than usual? Was it a freak event or the beginning of a new trend? There are a number of possible responses, which we shall now explore.

 

Response 1: Prepare better next time.

The river in Irwell Vale has burst its banks frequently in the past, but not usually to an extent that poses any risk to residents. The last time it caused a serious flood which led to widespread damage of homes was around 30 years previously. One might argue that this kind of ‘freak event’ only happens two or three times a century and so the residents should just shrug their shoulders, make repairs and remember to ‘be aware in a  couple of decades’. Sadly, this is not quite how probabilities work, so one should always be prepared for the next ‘once in 30 year’ event – it might happen tomorrow.

It was clear from the useless red bags that either the council’s effort to remedy the effects of flooding was far too little, too late, or that the forecasts they had only predicted shallow floodwaters. Indeed, flood forecasting is a fiendishly difficult exercise, with many complex interfering factors such as topography, road surfaces which keep water standing and forests which absorb water through the roots. In a valley bottom, the first hint of a flood should be taken seriously – perhaps more so than just attempting to block it on the doorsteps.

 

Response 2: Plan towns better in the future.

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The doomed Waterside pub

More critically, one might argue that the issue was not severe rain per se, but the fact houses, businesses and public facilities were built near to or in some cases on the river. Further downstream, the slightly misnamed Waterside pub collapsed due to the Boxing Day floods. This restaurant and pub had stood atop a bridge in Summerseat for 200 years and as the river levels rose, cracks began to appear in its walls, which eventually led to the destruction of the building.

As hinted at in the previous response, a less extensive use of tarmac and concrete would help to alleviate the destructive force of floods, allowing water to begin to seep into the ground.

 

Response 3: Stop causing climate change.

This is perhaps the most abstract response to floods, but is used frequently by environmentalists. The terms ‘global warming’ and ‘climate change’ don’t necessarily imply on their own that flooding will become more likely as these processes continue to make their impact. The diagram below illustrates how a rise in global mean temperature implies an increased likelihood of  extreme heat. The two Gaussian ‘bell curves’ describe the probability of a certain temperature occurring in a particular climate. In the grey case, extreme cold and heat are unlikely, but still possible. These probabilities are ‘shifted upwards’ on the temperature scale under climate change, defining new ‘extremes’.

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Redefining of norms and extremes

A Met Office report claims the likelihood of extremely hot summers has increased tenfold. That is, a ‘very hot’ summer will now occur roughly once every 5 years, compared with once every 50 years in the 20th Century. The 2003 heatwave which killed thousands of Parisians could be a regular occurrence by 2050. Extreme heat records since the millennium are within the bounds of a climate model forced by anthropogenic warming. However they do not fit within the bounds of natural variability so frequently used as an alternative explanation for heightened temperatures, as illustrated below.

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Model simulations of average summer temperature in Europe (black line) versus actual values (red). The left hand plot accounts for anthropogenic climate change, whilst the right allows only for natural variability.

As well as an increased likelihood of extreme heat, there is evidence to suggest ‘extreme weather’ such as flooding and hurricanes will also become more likely as a result of the altered state of the atmosphere. This is largely due to the fact that heightened temperatures mean an increased amount of water evaporating off the planet’s oceans. Many meteorologists claim the Boxing Day floods of 2015 were caused by the extreme weather brought by the periodic El Niño effect, magnified by climate change.

There is certainly plenty of truth in this argument, and a serious attempt to reduce the greenhouse effect would probably help to lessen the number of extreme events occurring across the world. A difficulty in it being widely believed is the fact anthropogenic climate change is hard enough to comprehend itself, let alone the way in which this could increase the amount of flooding across the world. Despite the value of the claims, I do not think temperature rise is the main factor leading to more frequent and more severe flooding across the UK in recent years. The real cause is much more tangible and potentially simpler to avoid.

 

Response 4: Reduce upland grazing and deforestation.

When pupils learn about the water cycle in Geography at school, they learn about how water evaporates off large bodies of water such as oceans, condenses to form clouds, falls down over land and runs back to the ocean in rivers and through the ground. Ideally, this process should take quite a long time in the part between precipitation and return to the sea. If rain falls and very rapidly reaches the sea, the volume of water flowing in rivers could vary wildly, from running dry to bursting their banks. What slows down the water cycle most is vegetation, namely trees and scrub.

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The water cycle

Roots of trees spread far and take in almost incomprehensible volumes of water, providing a ‘sink term’ for the water levels in the ground, to use an expression used in mathematical modelling. When trees are uprooted and removed, this effect is reduced and water is able to flow more freely through the ground, towards the river. Worse still, if forest and scrub are replaced by grass (or tarmac!), water becomes less and less likely to soak into the ground in the first place, tending to just run off on the surface.

I recently read George Monbiot’s excellent book on rewilding, called ‘Feral’, which simultaneously horrifies, educates and inspires. In a chapter called ‘Sheepwrecked’, Monbiot takes aim at farming of those fluffy, white herbivores as one of the biggest problems faced in the UK today, nicknaming herds of sheep as ‘the white plague’. Contrary to common assumption, sheep were at no point ‘natural’ residents of these isles and were imported for farming about 2,000 years ago. Their ancestors hail from Mesopotamia, domesticated there around 10,000 BC. As such, the natural environment in the UK has not evolved any mechanisms to deal with such ruthlessly hungry, low standing and mountaineering livestock.

Sheep will eat more or less any plant that they encounter, be it grass, bushes or small trees. Since resident plants have little means of deterring them, they largely succeed in eating whatever they want. Monbiot lists the mounting evidence to support the claim that sheep farming is highly responsible for the degradation of the UK’s rural heritage. For instance, sheep farming has been listed as a reason for the decline of wildlife in Wales in 92% of cases. Wales is well known for its sheep and an enormous 79% of the country is marked as reserved for livestock farming, with just 3% reserved for crop-based agriculture. Sheep are not the only type of livestock farmed in Wales, but they are by far the most common. Despite this extreme skew of land resources towards the raising of sheep, Wales imports seven times more meat than it produces and makes rather little on what it does.

A fascinating concept Monbiot discusses in detail is what he calls ‘shifting baseline syndrome’: You might think that your natural environment has degraded since your childhood, and wish for it to return to that state. But little do you know, it was already in a state of degradation then! This effect means many people underestimate just how badly humans have ruined the countryside and it is nowhere more evident than in the UK.

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Wast Water from Lingmell, Lake District

Despite its high population density, the UK boasts a number of large, popular natural parks and ‘wild’ areas – Snowdonia, Dartmoor, the Cairngorms, the Peak District, the Lake District. Whilst often staggeringly beautiful in their own ways (as seen above), none of these regions contains even a moderate amount of forest. All of these areas contain vast, open grasslands, scrub or bog, and all are grazed by sheep. Monbiot claims, with a large amount of scientific evidence, that the UK was covered in forest up until a thousand or so years ago. Personally, I have encountered very few forests in this country which couldn’t be crossed in an hour’s walking.

I am sat writing this piece at my mum’s house in the North East of Cumbria, which is often held as one of the UK’s most rural and ‘wild’ counties. Cumbria is not ‘wild’ in the sense of a natural environment. Cumbria is staggeringly barren and covered in sheep. Cumbria has arguably suffered worst from flooding in recent years… This is not to say that sheep farming is solely responsible for increased flooding, as I have discussed in the previous sections. However there is a strong, well-reasoned and inspiring argument that rewilding could provide at least part of the answer to the flooding problem, and I aim to look into it in detail in a future blog piece.

 

 

[Image sources: headerWaterside, bell curves, water cycle, Wast Water]

 

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