The Sliding of Solway Moss

by frankbeswick

In 1771 Britain experienced its worst ever bog slide when Solway Moss overspilled.

School books on social and economic history mention great natural events,but often they overlook small, but significant occurrences, and sometimes natural phenomena are discarded as insignificant. One phenomenon that has been neglected is the tendency of raised bogs to burst and slide downhill. One such event was the sliding of Solway Moss in 1771. But it is necessary to understand phenomena like this, as they still occur and may have consequences in an age of global warming.

Image of bog plants courtesy of Bergadder

Solway Moss

The Solway Firth [estuary] lies near the western border between England and Scotland, but during the Middle Ages the border was disputed and some lands on either side were called "The Debatable Lands."  Included in this borderland was Solway Moss, on the north  of the Solway Firth [estuary] in Cumbria, England.Its inhabitants were small farmers who eked out a living in the windswept, damp land and who used the moss, a typical raised bog, as a source of summer pasture and peat for fuel. I must explain that in Northern English usage a moss is a bog.For example, a bog near where I live is called Black Moss. 

Solway Moss has a grim history, for it was the site of a vicious battle in 1542 in which Henry the Eighth's forces won a victory over the seriously disorganised Scottish army. As usual, the aggressor was England's corpulent tyrant, who had invaded South West Scotland to coerce the Scottish king into accepting a reformation of the church on Henry's lines, which Scotland's Catholic king did not want to do,  but the badly led Scottish defenders were driven away in disorder. Many Scots fleeing across the Moss were drowned in the hidden mires.  

The bog had been growing since the end of the Ice Age twelve thousand years ago, but it had been shaped by human activity. The grazing of cattle had no effect on its structure, but peat digging did.The local people dug peat for fuel, and did so on the edges of the bog. They carted away the peat blocks, casually throwing the peat crumbs onto the ground, and these were trampled and compacted by footfall.  This process went on for millenia, and slowly, without anyone noticing a thick wall of compacted peat began to develop around the bog. This growth of an inadvertent damn went on for untold time. But to make matters worse, as the damn grew so did the bog. Rather than spread out as it would do naturally it grew upwards.

Bog growth is caused by the fact that sphagnum moss takes carbon and oxygen from the air, but does not decay properly, turning into peat, which traps CO2. Deposits of this semi-decayed plant resource accumulate over time, making bogs quite deep. In fact raised bogs can be domed in the middle. By 1771 the firm wall of Solway Moss was entrapping a bog that was fifty feet higher than the surrounding land, a vast reserve of soggy peat waiting to burst. 

Local people may have been aware of the danger, as bogs had slid before, though many would not have known of the large bog slide of Chat Moss near Manchester in South Lancashire in the seventeeth century, but they lived in hope and fear, trapped by poverty and unable to migrate to somewhere safer.Then in November 1771 came the deluge, a sustained period of heavy rain saturated the bog and soaked the damn, fatally weakening it. On November the Sixteenth the weakened damn gave way and millions of tons of peat began to slide slowly and inexorably towards the nearby River Esk, one of the rivers that flow into the Solway Firth 


A bogland
A bogland

The Sliding and its Consequences

The bog behaved like a lumbering Leviathan. It was not the sudden eruption of water that we see when a damn bursts, but more like a slow sticky lava crawling down hill. The local people had time to evacuate, and as they knew the size of the approaching monster they understood the severity of what was coming. Household goods were loaded into farm carts, children sent to relatives if they were too young to help with the evacuation. Cattle , sheep and pigs were herded to safety. Chickens were taken away in baskets, geese walked to neighbours out of reach of the slide, and all this work was performed frantically while the black wall approached. 

Landlords were impotent in the face of what was happening to their lands and stood helplessly before the impending, inexorable wall of peat.  They and their tenants watched as the mud reached cottages and used its weight to break their wattle walls and crash their thatched roofs. They observed well-tended gardens disappear under the advancing black ooze But this time scientists took an interest and recorded the event. This means that it was not only Britain's greatest bog slide recorded, but it was the one whose recording was done scientifically and then  studied. It was scientists who discovered that the bog's natural spread had been artificially, though inadvertently impeded by damning. It was scientists who first called the event the Eruption of Solway Moss. 

In all,  four hundred acres of farmland were fully destroyed, while other areas were partly affected. These acres have never been returned to agriculture, but  have remained waste afterwards. Though in World War One the disused land was conscripted into service as the site of an ammunition factory.  Effectively the bog spread to reclaim the land on which it would have spread naturally anyway. The landlords were not unkind and tried to find other land for their tenants. Fortunately, no one was killed, but some families were rendered homeless. 

Three years later there was a similar event further south when Pilling Moss near Lancaster, the County town of Lancashire [then] had a similar, though less severe eruption.     


Reflecting on the Event

The sliding of Solway Moss occupies a footnote in the history of North West England, but it makes us think. Events that are of minor significance in history are of great significance in the lives of those who suffer the consequences of this happening. The slide disrupted lives in an already impoverished, marginal area. Yet it has but a small place in the history books, but it had long term consequences for a small area of land. 

The significance of the event is that as nowadays we are encouraging the growth of peat bogs for their vital ability to act as carbon repositories we must be aware that these bogs can and will grow. This means that bogs in hilly areas need to be carefully monitored to ensure that their growth does not become so great that bog slides develop. About eighteen miles to the east of where I live there lies the two thousand foot Kinder Scout, whose peat bog summit is being restored so that the peat will thicken. The purpose of this much needed measure is to not only store carbon dioxide, but for the bog to act  as a sponge to soak up the mountain rains, which would otherwise flow quickly down the mountain side to flood parts of Greater Manchester, and as a resident of that conurbation I know the need for it. But integral to the strategy must be an appreciation of the dangers inherent in unchecked bog growth. 

Using peat has become something of a taboo in Britain on environmental grounds, and indeed we have damaged many of our bogs, but there could be a case for the managed extraction of peat as part of a bog maintenance strategy. The Irish use much peat on their fires, for it is a natural resource abundant in that land, as it once was in Britain. 

Updated: 04/19/2018, frankbeswick
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frankbeswick on 01/23/2020

Nice to hear from you again, Derdriu.

A good book for studying bogs is David Bellamy's Ireland.

Solway Moss was grazed carefully, but not overgrazed, so it never suffered ecological degradation.

DerdriuMarriner on 01/23/2020

frankbeswick, Thank you for the practical information.
How can there be no product lines associated with your timely article? Do you know of book, journal or online sources that you'd recommend for raised bogs and Solway Moss?
It's interesting that "The bog had been growing since the end of the Ice Age twelve thousand years ago, but it had been shaped by human activity. The grazing of cattle had no effect on its structure." Is it that the numbers never kept the bog from structuring as it should or just that grazing never would have impaired Solway Moss?

frankbeswick on 03/27/2018

Chat Moss, north west of Manchester, is on very flat ground, but it slid in the seventeenth century because it was domed and and outward pressure forced the peat to expand. But this moss was taken over and claimed for agriculture, a land use that took away some of the expansionary pressures on the peat.

frankbeswick on 03/27/2018

There are different kinds of bog, each with their own characteristic vegetation. Raised bog is a filled-in swamp/fen, which can be dome-shaped, and this tens to slide when on a slope. There is upland blanket bog and lowland, which tend to be less prone to sliding, though these kinds can slide. Raised bogs are made of decayed sphagnum moss and they contain much water, rendering them unstable.

In Ireland when I was walking on the slopes of the Glenfarne Plateau in County Leitrim I encountered a situation where swelling bog had produced not a slide, but the rising of a massive block of peat about six feet high and I don't know how long and wide The bog was filling up and as it was confined between stone walls had to swell upwards. It is situations like tis that make me disposed to mine some peat to keep the bogs stable.

Sphagnum moss can and should be harvested, as it makes a great antiseptic wound dressing, and was used for this purpose in World War One

blackspanielgallery on 03/27/2018

I was unaware of bogs being able to move out and act as a landslide.

frankbeswick on 03/27/2018

The cockle fishers could have been saved had they been on the beach, but they went out at night too far onto sandbanks where no wise person treads without very good cause and even then not alone.The tide there races in faster than a person can run. You are right about the role of the narrow channel between Britain and Ireland not far north of this region, for the currents through the narrows are strong and dangerous and then they meet a powerful flow surging out of the Solway.

Veronica on 03/27/2018

Again the beauty of Wizzley for me is its educational value. It is like doing a world tour with experts. I love reading about all these features from around the world.

Frank and I live over 50 miles from the North West coast. It is exceptionally beautiful, but treacherous and dangerous land. A few years ago there was a major disaster when some illegal cockle fishers were stranded and killed on the beaches at Morecambe bay . Further along, a horn sounds to announce The Bore is due to sweep in down the estuary and people evacuate.

Beautiful and deadly. Part of the trouble is indeed the Irish sea which flows narrowly between England and Ireland.

frankbeswick on 03/27/2018

The speed of flow depends on gravity. On a slope it can be fast indeed, but the problem at Solway Moss was that while the land sloped but gently, the bog was fifty feet higher than the surrounding land. The peat is also more viscous that mud, so it slid more slowly than a mudslide does.

An ammunition factory was erected on the site and worked for a few years, but generally land in that region is hard to farm. It is quite marginal, and many farmers have to work hard to keep their land from becoming waterlogged. The factory is now derelict. I would not buy land round there.

frankbeswick on 03/27/2018

Thankyou. The Solway Firth is a dangerous place, with the powerful estuarine flow meeting tides and currents sluicing south down the Irish Sea.

dustytoes on 03/27/2018

I've never heard of such a thing. I'm curious as to why no one built on the site after the slide. Is there simply no good dirt to use because it is covered in peat? How fast does this kind of thing move? Is it like a mudslide?

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