the art of field drainage by Philip Walling

The Beauty of Field Drainage, by Philip Walling

That works of draining are most ancient and of divine institution we have the testimony of Holy Scripture …  That those nations which be of greatest antiquity, and of chief renown for arts and civility, are also famous for their works of this nature, is evident from the practice of the Egyptians, the Babylonians, the Graecians, the Romans, and several others of which I shall give instance.  From: The History of Imbanking and Drayning by William Dugdale, Esq., Norroy King of Arms. 1772

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One calm frosty autumn morning, when I had been working for a couple of months for Dick Miller at Home Farm, Tallentire, I turned up in the yard to start at 7.30. The boss was leaning on some long-handled implement I’d never seen before, talking to the farm lad. He lifted his head as I walked towards them and said ‘Right, git a spèade and foller me!’ and the two of them set off towards the bottom fields.

I went into the workshop and selected a spade I liked the look and feel of from the rows of hand tools hanging from wooden racks on the back wall and followed them down the track, running to catch up with them. For a stout man in late middle age, who enjoyed his food, Dick was a surprisingly quick walker. He and his scrawny assistant were almost at the edge of the bottom field before I did catch up with them. Dick was carrying over his shoulder the tool that he had been leaning on earlier in the yard and as we approached the hedge and ditch that marked the boundary of his land, he handed it to ‘the lad’ and held his hand out for me to pass him the spade.

‘This isn’t a ditching spèade; you should have fetched yan with a roond mooth!’

‘I’m sorry I didn’t know what kind I needed. I didn’t know what we were going to be doing,’ I replied rather lamely.

‘I would have thought it would have dawned on you when you saw me leaning on a muck-drag.’

I looked more closely at the implement the lad was now leaning on. So that was its name. It had a long shaft fastened to a fork with six long thin pointed tines bent at right angles to the shaft.

‘It’ll have to do; you haven’t time to trail back up to the farm for another spèade. You’ll learn from your mistakes.’

He stabbed the spade into the mud and tangle of roots and vegetation that were clogging the ditch and cut out a square chunk to show me how deep he wanted me to go. Then he cut along the edge in a long straight line for a few yards and back again with another line about a spade’s width apart. Then he cut across between the lines to make square spits. The spade was sharp and cut cleanly about a foot down into the mud and roots; it was just like cutting up a large cake.

Then he took the muck-drag and swinging it two-handed like a mattock stuck the spikes into one of the squares he had chopped and dragged out the waterlogged cube onto the bank. He repeated the action with some of the others, laying them neatly upside down and side by side on the bank.

‘Right! Get the idea? The lad’ll keep you right!’

And he nodded to the lad, who nodded back at him.

He then handed me the muck-drag and motioned for me to show him that I had picked up how to use it. I swung it as I’d seen him do and embedded its tines into the next cube and dragged it to the bank where it slid off the spikes. I did it again a few more times without difficulty and he seemed satisfied, because without a word he took off up the field into the rays of the low sun that was just coming up over the high fells, dissolving the frost that had whitened every blade of grass, as it moved across the field. Dick stumped away and didn’t look back. He didn’t like wasting time and to him walking was wasting time, so he got it done as fast as he could.

The ditch was about a yard wide and stretched away, up the long field beside a hedge, for what I judged to be getting on for 500 yards. Dick had started us digging at the lowest point where the water that was meant to flow in the ditch ran away down a low stone culvert into the next field. Ray, the lad, was a little older than me and, considering his slight frame, was surprisingly strong. It was sad that he got no joy from his work which he saw as pure drudgery that he did to earn money.

Ray carried out his orders reasonably conscientiously, but he never did more than exactly what was expected of him or worked a moment longer than he had to. I had worked with him for about three months, since the summer, but never in such close company before and I had never had much of a conversation with him. As we worked he began to talk, a little cautiously at first, because I thought he saw me as the boss’s stool pigeon and wasn’t sure how much he could trust me. He was mainly interested in talking about his girlfriend who had rejected him for another, and in extravagantly lurid terms what he intended to do to his usurper if he ever got the chance. I tried to persuade him that it wasn’t worth getting a criminal conviction over a ‘mere woman’, but he must have disagreed because a few months later, one morning he didn’t turn up for work. When Dick phoned his mother to find out where he was, she told him that he had been arrested for ‘an assault’ and was on remand. We never saw him again.

But, on that sharp still autumn morning, with not a whisper of wind to disturb us, we took it in turns with the spade and the muck-drag, up to our knees in water and ‘sluther’, as Ray described it, drenched in sweat, to work our way up the ditch. We dug the channel six spits wide and two spits deep and made a bank with the field side sloping slightly outwards and the ditch side much steeper. We were going along at a good rate; Ray was dragging out the spits I was cutting with the spade, when on the field side of the ditch I struck something that sounded hollow and gave way under the slice of the spade; straightway a gush of orange brown water came out of the side of the trench and flowed into the ditch. When I dug in a bit further a short piece of orange clay pipe came to the surface and the water really began to flow full and clear, carrying pieces of small gravel and coarse sand that danced in a little eddy out of what I now saw was a clay drain pipe, or ‘tile’ as Ray told me it was called. Gradually the flow diminished to a trickle, but it did not stop.

Ray didn’t seem interested when I pointed out the water flowing from the drain.

‘Aye! It’s the outfall from a drain tile. They’re the buggers we’re supposed to be cleaning out,’

So we pressed on with the digging and eventually nine yards (I paced it out) further up the cleaned-out ditch we uncovered another outfall and the same happened again, a rush of pent-up orange iron-brown water was liberated and flowed into the ditch when we dug the ‘sluther’ and sod away. And when I looked up the field, I could just make out long straight shallow depressions running at right angles to the ditch, every nine yards. Buried in those I supposed the drains must lie.

I didn’t notice Dick until he was standing over us, looking down into the ditch, but Ray must have seem him striding down the field and said nothing, because he suddenly speeded up his work and put more effort into it.

‘No wonder this field’s so bloody wet!’ Dick exclaimed and waved one exasperated arm towards the lower half of the field nearest where we were digging, and tossed an oval-mouthed spade in my direction with the other, which I caught in one hand by the shaft. It was only then that I really looked at the surface of the field and could see that on the part nearest the ditch it was pocked with small puddles that had formed in the hooves of cattle that had plunged deeply into the soil.

Dick said, ‘Getting these drains flowing should dry out this bottom half of the field and stop the beasts poaching it. Keep at it lads until dinner time.’

And he strode off again.

I knew that beasts were cattle, but it was the first time I had heard poaching used to describe the damage that their plunging hooves did to soft wet ground. I wondered how many people who had never worked with a spade and a muck-drag clearing a drainage ditch, would have had any idea what he was talking about. By noon, when we downed tools for dinner, we had dug and cleared about 50 yards of ditch and unblocked six outfalls and the water was flowing freely in the part we had cleared.

Nowadays, if this ditch cleaning is done at all, it would be with a mechanical digger in a couple of hours, but Dick believed in having plenty of labour on the farm and seeing as he had it, he used it. We finished the ditch in three days. I had bleeding blisters on both hands but once they hardened into calluses I never had another blister from using a hand tool all the time I was farming.

A typical outfall into a ditch from a 3″ clay tile.

A typical outfall into a ditch from a 3″ clay tile.

This was my introduction to a thing that is too little known: that under the surface of nearly every field in Britain lies an intricate pattern of field drains silently carrying away the surplus water. Without these drains a significant part of the farmland of the British Isles would be either practically unproductive or certainly much less productive than it is. There are millions of miles of these drains under millions of acres, dug with backbreaking physical labour, culminating in a frenzied forty years between 1840 and 1880, and most are still functioning today. They are the hidden part of the huge eightenth and nineteenth century capital investment in money and human effort in the farmland of Britain, that we now have neither the will nor the skill, nor the wealth to replicate. They have been flowing water in the earth for all that time, in wet times and dry, silently carrying away the surplus groundwater, while all the events of the last two centuries have swept over the fields above. It is marvellous to contemplate the astonishing skill and energy of the men who dug these drains and laid them out with such accuracy.

The purpose of field drainage is to regulate the moisture content of the top two or three feet of soil so that it is dry enough to cultivate or graze for as long a period of the year as possible. The aim is to make it as near as possible the ideal self-draining soil. This is a soil that is never waterlogged in winter, never dries out in summer and is capable of allowing all surplus rainfall to percolate down into the subsoil, yet absorbs and provides all the moisture growing plants need during times of drought. It hardly needs saying that there is precious little land like this in Britain. Few useful crops (except perhaps rice or watercress) will grow if their roots are waterlogged and deprived of oxygen. And all soils will benefit from drainage where the groundwater rises high enough in the subsoil to prevent the roots of plants penetrating to the full depth required for their proper growth.

An unstable outfall from a horse-shoe tile set on a base plate.
Note the erosion of the subsoil and undermining of the base plate.

An unstable outfall from a horse-shoe tile set on a base plate.

Note the erosion of the subsoil and undermining of the base plate.

Anybody who has ever kept a house plant will grasp that plants need the soil to be neither too wet, nor too dry, but just right. Many plants need watering from below to encourage their roots to search for moisture and will not tolerate the surface being waterlogged. This mimics, in a plant pot, what happens on a larger scale.

Rain in the British Isles falls more or less evenly throughout the year with a general rule that more falls in the north and west of the country than in the south and east. We have no monsoon, or dry season. And we can judge just how infrequently extremes do occur by the national dismay which accompanies the occasional heavy rain or drought. But what we do have is an unusually wide seasonal variation in the humidity of the air and its capacity to evaporate water from the soil.

If rain falls on permeable self-draining soils it will percolate downwards through the layers of earth and the soil will quickly become too dry. If it falls on impermeable surfaces, such as clay, through which it cannot percolate, it will build up on the surface until the topsoil rapidly becomes too wet. Evaporation exceeds rainfall in eastern England from about March to August, and in the west from April to July. This means that from the onset of spring, the soil is drying out and its capacity to absorb rainfall increases up to the point of maximum evaporation at about the end of July or August. Thereafter, until February, the soil becomes progressively less able to absorb water as autumn and winter rainfall exceeds evaporation.

Unless it rains, the soil dries out gradually from the surface downwards. During the summer, moisture evaporates rapidly and so the rain that falls only makes up the deficit in the top few inches of soil, not penetrating very deeply before it is evaporated. That is why watering a garden in summer often does more harm than good because it fails to replenish the moisture in the soil below the top inch or two, so discouraging plants from sending their roots into the subsoil in search of water.

When in the autumn, rainfall again exceeds evaporation, the soil moisture is gradually replenished from the surface downwards. Once each layer of soil has been rehydrated to its maximum capacity, the surplus percolates deeper through the permeable layers until it reaches an impermeable layer; this can lie a few inches below the surface on clay subsoils, or on chalk soils, the permeable layer can be very deep. In chalk country, neither the soil nor subsoil holds water long enough to sustain useful plant life. In all soils there is an underground level where the soil becomes saturated with ground water. This is the water table. As a general rule, the larger the particles of matter making up the soil, the lower in the sub-soil lies the water-table: in chalk and gravels it lies a long way from the surface because they are the most permeable materials; clay is the least permeable – sometimes practically impermeable – because its particles are so small they allow almost no air between them. In such soils the water-table can be close to or at the surface.

Proper under-drainage of land was far from new in the closing decades of the eighteenth century, but it had hardly been applied in Britain. The greater part of our farmland was affected by seasonal waterlogging and land drainage had become the crying need of the day, if the nation was to feed its burgeoning urban industrial population. It was well-known that nearly all soils, especially the potentially highly fertile heavy clays, were unable to yield according to their capability because the water content could not be regulated. Clay soils are the most promisingly fertile because they contain more plant nutrients than lighter soils, particularly potassium, but they are difficult to work without effective drainage. They become too wet to work much earlier in the autumn, and when they dry out in spring, they become hard and intractable, and set like concrete. Where clay soils are in pasture and ineffectively drained, the coarser, less palatable moisture-loving plants tend to overpower the more nutritious herbage, especially when the surface has been damaged by poaching.

If British farming was to rise to the occasion of feeding the towns, it became imperative to lower the water-table across millions of acres of its soils. The time-honoured principle which was known to the Egyptians, Greeks and Romans is to dig trenches in the soil at different depths and distances apart – depending on the type of soil being drained – into which the groundwater will be attracted and flow away. These trenches were filled in with some material that would be more permeable than the surrounding soil and form an underground channel; the topsoil would be replaced so that cultivations could be carried out across the whole surface of the land.

Although the Romans practised this type of draining across the Empire, it was limited to small areas in England and fell into disuse after the Roman occupation ended. Certainly by the time of the Anglo-Saxon settlement the usual method of getting rid of surface water on arable land in England was by ploughing the land in ridge and furrow. Surviving examples of these corrugations can be seen in certain places, mainly in England, where former arable land has been allowed to fall back to pasture without levelling off the ridges. They are particularly evident when a low winter sun throws long shadows across the fields, or when the undulations are picked out after snow has melted from the warmer drier ridges, but still lies in the furrows. In Northumberland there are many fine examples of remaining ridge and furrow. They have largely been preserved because agricultural depression made the land not worth ploughing for arable crops. They are now mostly protected by state control, although some were lost when every acre of potentially arable land was ploughed during and after the last war.

Until the enclosure of communal open fields, the land was worked in strips, called lands, which were from 3 to 15 yards wide, and of varying length. A parcel of strips all running in the same direction was a furlong (Old English furrow-long, or cultura in early legal language). Each field (campus) was made up of scores of furlongs and hundreds of strips of varying shapes and sizes. The average strip was about 11 yards wide and 220 yards long – about a quarter of an acre. The crops were grown on the seedbed created on top of each ridge, where the soil dried out quicker because surplus water ran off into the bottom of the furrow which acted as an open field drain or shallow ditch. Their layout depended on the lie of the land and the type and quality of the soil. Each individual farmer’s holding of strips was known as a yardland. In the Domesday survey the value of each township was assessed by the number of yardlands it contained, with ten yardlands equalling a hide – the amount of land that would support a family.

A distinctive feature of these ancient ridges from the Early Middle Ages, is that they usually describe an elongated mirror image of an S at the ends of the ridges where they abut the headland – the last part to be ploughed round and round, rather than up and down, on the edges of the field. This reverse S shape of the ridges was caused by the way the teams of oxen were turned at the end of the ploughing. If we imagine a dog-team attached to a sled by a long trace, in order to keep the following dogs pulling straight, the leading dogs would have to keep pulling beyond where they wanted to turn. And then they would swing round in a wider arc than the following dogs. The manoeuvre requires them to pull slightly to the left before swinging round wide to the right; this keeps up the traction, while the dogs nearer the sled travel a shorter distance to make the same turn.

Applying this principle to a team of eight oxen many yards long, yoked in four pairs pulling a heavy, mainly wooden plough, if the leading beasts simply turned right when they reached the end of the ploughing they would tend to drag the following animals over the land they had already ploughed and spoil the work. To make sure the following animals would still be pulling straight down the furrow, as each leading pair reached the headland at the end of the ploughing they would be turned left and lined up on the headland, while the stronger oxen following behind would keep pulling the plough straight down the furrow for the last few yards until they too reached the headland and turned left to stand behind the previous pairs. Then, when the last pair reached the end of the ploughing they would turn right to follow the first three pairs which had been turned right along the headland. The whole team would then proceed along the headland crossing the end of the ploughed strip before the leading oxen would swing round to the right in a wide circle and turn across the unploughed land to bring the plough to join the next furrow. The last pair of oxen would simply turn right into the ploughing bringing the plough round to the beginning of the furrow, whereas the first three teams would have swung in diminishing arcs before straightening up into the furrow. If each team was simply to turn right when they reached the end of the ploughing the leading team would have passed the new furrow before it could turn in to the ploughing and would have to be turned sideways to join the new furrow. Whereas lining up the oxen to the left and turning the whole team as one to the right meant the turn could be done in one movement.

As the Middle Ages progressed ploughs became more efficient and oxen bigger, and as fewer oxen were needed in a team, so the ploughing became straighter and began to lose its reverse S shape. Also the headlands became narrower because the ox teams needed less land to turn into the next furrow.

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field drainage is complexThere are some pieces of land that are almost impossible to drain. In one of my fields there was a little basin, lower than the surrounding land and the nearby stream, but it was nonetheless always dry, never holding any standing water. But one winter it filled with water and a little pond formed. I got our local drainage man with his JCB to come and investigate. He was baffled by the water welling up through the turf. There was obviously a drain there, and it must have been blocked below where water was flowing from because water will not flow uphill. But there was no sign of a pipe. In fact, when we roughly checked the levels, the pipe must have been lower than the stream and could not have been discharging into it. The problem with blocked drains is that you are nearly always digging in muddy water and cannot see what you’re doing. It mostly has to be done by guesswork and trial and error.

As the bucket of the JCB cut deeper into the soil the water flowed to the surface quicker and cleaner. But there was no sign of the drain. As we dug deeper and deeper the hole filled with water which overflowed across the field. We decided to dig a dry hole below this hole, along the line of where we thought the drain must be. We guessed where the drain ought to run and dug a six-foot deep trench at right angles to it hoping to encounter the drain at some point. Nothing. The JCB man went back along it digging the trench another yard deeper and exactly where we guessed the drain ought to flow the teeth of the bucket engaged with a huge blue-slate flagstone. He dug around it and eventually exposed it. There was a hollow ringing sound when I jumped down into the hole and struck it with a crowbar.

Now, almost at the limit of the JCB digging arm (they didn’t have extending arms in those days) he managed to get the teeth of the bucket under one corner and prize it up. The blue stone slab was about four inches thick, two feet six wide and six feet long and must have weighed half a ton. It was sitting on a stone culvert made in a box shape with a similar flagstone on its base and smaller ones making the sides. A trickle of muddy water was flowing along the bottom. Where on earth did the water come from – and where was it flowing to?

We were now at least ten feet below the level of the stream flowing about 200 yards away at the edge of the field. I screwed together a dozen draining rods with a little brass wheel on the end to ride over the joints and cracks, and fed then up the culvert until they came to a dead stop. I banged them a few times against what was stopping them, but to no effect. We could work out the line of the drain and measure the distance to the blockage by laying them along the surface and the JCB man went back along and started digging just below where it appeared to be blocked. He reached another big blue flagstone at about three yards down and dug it out to open the culvert, still flowing muddy water. We pushed the rods in again, this time with a double screw on the end and twisted them to screw into the blockage. This time the rodding moved something, because all of a sudden a great rush of muddy water came down the culvert and I had to jump out of the hole sharply to avoid my wellingtons filling up.

Very slowly the pool of water began to drain away. But where to? We followed the line along which we thought the culvert must run, crossed the stream, the next field, over a hedge and across the public road, and across another field, following the fall in the land. At the boundary of my land we crossed into my neighbour’s field where it bordered the river, and there flowing from a culvert that emerged from the river bank, about a foot or so above level of the river, was a flow of muddy water.

I had never noticed this drain before, even though it drained my land. The outlet was at least seven hundred and fifty yards from where we had been digging into the blockage, and in places it must have been twelve feet deep. But the marvellous thing was that it had been dug underneath the stream to get a fall. I could not even begin to understand how the old drainers could have done that. And all to drain a piece of land no bigger than a medium-sized garden.

When I told the Mackereth brothers, the previous tenants of my farm, they said they knew about the culvert, but that it had never blocked in the almost a century their family had been on the farm. They said the tenant before them had told their father before the First War that it was a medieval drain from an underground spring that rose somewhere further up the hill behind the farmhouse.

There had been a farm on the site for a very long time (long before it had been renovated in 1670) and there was no running water anywhere near. This always puzzled me because every other farm in the valley had been built close to a natural spring or stream. It set me wondering whether the ancient deep culvert had not drawn away a spring that might have watered the farm house and buildings. I could never find any trace of a spring, but then I didn’t look very hard. I never found the source of the water in the culvert either. It is nothing short of miraculous that this very deep culvert should have been dug out and lined with flagstones maybe a thousand years before I found it and that it had been flowing water deep beneath the earth for all that time, in wet times and dry, while all the events of history swept over the fields above.

I was awed by the instinctive skill and energy of the men who dug this drain and laid it with such accuracy that it ran water for so long. Such work is one of the hidden wonders of the English countryside.

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