The Spirit of the Downs
Home Up

 

The Spirit of the Downs

CHAPTER XX

A DISSERTATION ON DOWNLAND DEWPONDS

I was told that there dwelt in one of the cottages of Glynde a man who had been accustomed to construct dewponds on the Downs for more than sixty years. Thither I repaired in the company of Mr. Pickard, the Steward of the Glynde Estate.

The old man's name was Weller; and though over eighty years of age he was full of vitality ; and he now stood before me a testimony to a healthful, if hard life spent in the Sussex hills.

"Will you tell me how you used to make dewponds ? I asked.

The ancient looked puzzled, and shook, his head.

" Sheep-ponds," explained my friend, the Steward.

" Oh, ship-ponds, " repeated the old man in his vernacular;

I didn't know what you meant when you talked about dewponds ! "

And though most men use the term " dewpond " to describe the circular shallow pools of water that are scattered all over Downland, hardly a man who makes them, or a shepherd who waters his sheep at them, knows them by any name other than sheep-ponds."

The subject of " dewponds " has proved of fascinating interest to many observers, both scientific and merely curious. Much evidence, both proved and supposititious has been brought to bear on the controversy which has centred round the question : From what source or sources is a dewpond supplied with water ? The evidence is somewhat difficult to balance in order to get at the facts of the matter ; but I shall here attempt to set forth the conclusions arrived at by several inquirers who have interested themselves in the subject, some of whom have kindly placed their deductions at my disposal for this purpose.

The pedestrian who walks through the Downs will notice scores of round, shallow ponds, mostly placed on the summits of high hills and used for the purpose of watering sheep and cattle. So many saucer-like depressions, half-filled with liquid, will probably strike him as singular, as in no part of the country is the dewpond more common than among the Sussex Downs. The question that will naturally arise to his mind is: How are these ponds supplied with water, since no springs are near, and the nature of the chalky soil being distinctly porous, no appreciable supply of surface water can, apparently, drain into the pond ? He will also remark that even in the driest summer these dewponds, like the widow's cruse, never appear to be empty. The popular belief is that the water comes from deposits of dew; and in their "Neolithic Dew-Ponds and Cattle-Ways" Dr. John Hubbard and Mr. George Hubbard, who believe that they have discovered signs of dewponds of Neolithic origin in the Downs, argue that as some convenient source of watersupply was necessary to prehistoric man, frequenting as he did the slopes of the Downs for the safety of himself and his cattle from the terrors of the forest and the plain below, it is quite conceivable that he constructed ponds on the top of the hills to serve this purpose.

In refutation of this theory, it is known from the charcoal found in Neolithic sites that the climate of that period, even on the Downs, was a damp woodland climate. The question of water-supply in the Downland valleys cannot therefore have been a difficult one, as is commonly supposed.

After reading the Hubbards' book I was led to seek out Weller, an experienced dewpond maker of Glynde, in the hope of acquiring some information concerning both ancient and modern dewponds. But before seeking Weller I was fortunate enough to meet Mr. Pickard, the Steward of the Glynde Estate, who himself has had much practical experience in the making of these watering-places, and who, in consequence, holds decided views on the subject.

I was informed that in addition to old Weller's personal experience, gained during a lifetime in the building of these ponds, he had been brought up in the traditions of his father and grandfather, who were employed in similar work before him. The method followed by the Wellers was this : A suitable site having been chosen, the ground was hollowed out to the desired depth, and the excavation covered with a layer of mortar, into which a course of flints was rammed. This process was repeated in a similar manner, so that the lining of the pond consisted of two courses of mortar and two of flints, in alternate layers. On the last course of flints was laid a " compo " of plaster and fine sea-sand, and, finally, the pond was finished with an edging of brick, nine inches wide.

The lining of the pond had to be laid in a special manner. Starting in the centre of the excavation, a small circle of the coating material was deposited and beaten in, and this was extended in ever widening circles until the outer circumference was reached. Such was the method employed by Weller and his father and grandfather before him, and, so far as the old man could remember, he knew of no other manner of construction that had obtained previously.

But I was able to learn from another source that before this method of constructing dewponds came into vogue in the South Downs, it was customary to use cattle for the purpose of puddling the clay lining. In a recent instance the water in an old dewpond on Heighton Down was kept from percolating through the clay to the chalk beneath, owing to the frequent puddling of a herd of Highland cattle, which were accustomed to water there. The herd, entering the pond to drink, would tread the clay bottom after their manner, thus rendering it practically impervious to leakage. In the South Downs many of these old ponds have been repaired and adapted to modern use. Such ponds may frequently be recognized by reason of the steepness of their slopes, which is greater than that adopted in making modern ponds.

Asked as to the source of water-supply, Weller stated that this was due chiefly to the rains, and, in a much smaller degree, to mists and sea-fogs. He laughed at the idea of dew forming any considerable factor in the supply. The theory advanced by Messrs. Hubbard that the supply of water is due to the condensation of the atmosphere seems to be negatived by an example given to me by Mr. Pickard. A few years ago, during an exceptionally dry season, a dewpond was constructed on the Downs between Glynde and Newhaven. For three months no rain fell, and although the dews were exceptionally heavy, the pond, during that period, remained quite dry. When rain eventually came, it filled rapidly. Mr. Pickard tells me of a similar experience of a pond at Tarring Neville, which he had repaired during the summer of 1908. The pond in question was very badly cracked and leaky, and was, therefore, relined with concrete. A gravitation pipe was put in to conduct the water to a trough some distance away, so that the sheep should not enter the pond and foul it. For some time after those repairs had been carried out. Mr. Pickard kept the pond under observation. During the rains of August and early September, the water stood four inches above a special mark, and although mists and fogs were frequent, the water fell three inches until the next rain came to raise effectually its volume and allow it to run through the pipe again. Again, at Toy Farm, between Glynde and Seaford, during the summer of 1893, one of the driest seasons on record, two or three hundred gallons of water had to be carted to the farm dewpond every day for the use of the stock during a period of seven weeks. Such instances appear to be strongly against the theory of supply advanced by Messrs. Hubbard.

Under the guidance of Mr. Pickard I inspected some of the most recently-constructed dewponds on the Glynde Estate. The method employed in their making is the result of long experience and experiment which Mr. Pickard has been able to bring to bear, and appears to me to be thoroughly scientific. After the ground has been hollowed to the required depth, a course of two-inch flints is made into a " cement concrete aggregate," and is laid down and rammed to a thickness of four to six inches. leaving a rough surface. Boards having been laid from the rim of the depression to the centre, for the convenience of the workmen, a composition of Portland cement and coarse sand is wheeled out and plastered upon the course, to a thickness of about one inch, so stopping all crevices, and rendering the whole one solid mass, which (if sufficient strength could be used) might be lifted up whole, like a saucer. The water, during rains, flows in by means of the natural channels of the hills, passing through a simply constructed filter placed at the outer rim of the pond. Such ponds cost about eighty pounds each, their upkeep is an almost immaterial item in farm expenditure, they are practically everlasting and always contain plenty of water. On the other and, the old dewponds, as made by the Wellers, would last about twenty years; upheaval and worms would crack them, and vegetation accumulating in the cracks would cause leakage.

Dewponds are generally made in the spring when the weather is settled, as frost is fatal to a newly-built pond. They are generally six feet deep in the centre, sixty feet in diameter, and some have an additional border, of concrete, twenty or thirty feet wide. Five hundred sheep may be watered daily at such a pond without, under normal conditions, seriously diminishing the supply of water.

The largest dewpond in Downland is situated on the summit of Chanctonbury, some distance south-east of the Ring. It is sixty or seventy feet in diameter, and is surrounded by a deep trench cut in the face of the hill. From the fact that the trench and mounds are carried round the exposed side of the pond, and extend in each direction for some distance, in such a manner as to furnish cover along the steepest part of the ascent, Messrs. Hubbard argue that this Chanctonbury pond is of prehistoric origin. They proceed to point out that the space between the dewpond and the Ring is entirely open and unprotected; and that not only do the earthworks surround one side of the pond, but as they extend to the east they enclose the remains of a primeval dwelling or watch-house, which is marked by a circular depression in the ground.

This pond and a smaller one, according to the Hubbards, furnished the water-supply of the ancient inhabitants of the Ring, and thus they account for the care expended on the elaborate fortifications, which must have been built at a cost of almost incredible labour. Indeed, so far from the larger dewpond near Chanctonbury Ring being of Neolithic origin, Dr. Eliot Curwen has spoken with one of the men who helped to make it! The earthwork, of " covered way" type, curves round the site of the pond, but Messrs. Hubbard fail to take into consideration the possibility that the pond may have been built on the site of, say a barrow which antedated the earthwork. The date of this type of earthwork is altogether uncertain, but there is some evidence that it may date from the Bronze Age. But it is to be noted that Hadrian Allcroft, in his " Earthwork of England," is of opinion that neither of these two ponds is more than forty years old ; and that, as Mr Allcroft points out, when the late General Pitt-Rivers excavated here in 1868-9, the site of one of them was a mound; and that Pitt-Rivers fails to mention the other pond, although at the time of his excavations he was inquiring into the question of Neolithic water-supply. As a result of his investigations, it is interesting to note that he favoured the theory that water was obtained by the Neolithic tribes from streams which then ran at a higher level than now.

In support also of Mr. Allcroft's opinion (given above), I am able to quote Mr. J. Morgan, who, in 1908, made certain inquiries concerning the large dewpond on Chanctonbury. The driver of the coach in which Mr. Morgan and a friend went from Worthing. told them that an old man, a labourer on a farm near, who had recently died, had assisted in making the pond. The process of construction was thus described : First, a large hollow basin was scooped out of the chalk, and then lined with hay or straw. Upon this a thick coating of clay was put and well puddled until it would hold water. About a ton of water was then placed in the pond as a nucleus, and forthwith, night after night, water accumulated, and a permanent supply was thus formed.

Mr. Morgan then proceeds to state that from a resident of Worthing, who has been familiar with the Downs all his life, he subsequently learned that in making this particular pond, as well as two others near the Ring, no straw was used ; but on the bottom of the chalk basin a layer of flints was laid, and well pressed in with an agricultural implement; and upon the flints was laid the coating of puddled clay, this last material being obtained from pockets close by. The same informant also pointed out to Mr. Morgan that several alleged dewponds, including that on the side of the Long Furlong Road, between Findon and Patching, are fed only by drainage of the rainfall, and in hot summers are dried up. 1

There is an old clay pond on Beddingham Down to which a former tenant of the farm was accustomed to cart a considerable quantity of clay every few years, for the purpose of relining it. He would then puddle the clay with a bullock-team, after which the bullocks were hitched to a heavy roller, and the process was repeated. Thus a certain amount of water was kept in the middle, of the pond to throw over the clay as the work proceeded, for the purpose of preventing it from sticking to the roller. The Beddingham pond has not held water for several years, and there are now rushes growing in it, the roots of which were, no doubt, carted there in the clay when it was brought from the marshes below.

In four examples of dewponds - those constructed or quoted by Clutterbuck, Slade, Desmond, and the Hubbards - cited by Mr. Edward A. Martin, F.G.S., in a series of articles contributed to " Knowledge and Scientific News " - straw forms an important feature in the construction, the Hubbards placing the straw at the bottom of their pond, the other three making it the section intervening between the layers of lime-tempered clayland broken chalk or rubble; or, in the case of Desmond, between two layers of concrete.

The object of the straw is, of course, to act as a non-conducting medium of heat, as it prevents the warmth of the earth from imparting itself to the clay, which becomes chilled in the process of evaporation. It is important, therefore, in constructing dewponds in which straw is used, to protect carefully the margin of the straw, as if it once becomes wet it will cease to attract moisture.

The theories held by Gilbert White and Richard Jefferies on the question of water-supply to dewponds that came under their personal observation are worth noting. White quotes the case of a pond on the sheep-down at Selborne, three hundred feet above his house, " which, though never above three feet deep in the middle, and not more than thirty feet in diameter, and containing, perhaps, not more than two or three hundred hogsheads of water, yet never is known to fail, though it affords drink for three hundred or four hundred sheep, and for at least twenty head of large cattle besides." He then argues that the pond in question, which " is overhung with two moderate beeches," receives, at times, drippings of water from those trees. On the other hand, he gives the case of certain ponds which " constantly maintain a moderate share of water, without the aid of trees, and in spite of perpetual consumption by cattle, although they are not replenished by springs."; and he seems to deduce from the fact that, although pools in the vales are sometimes dried up during drought, the small ponds on the top of the Downs still contain water, the view that this is because evaporation goes on at a greater rate in the valleys than on the hills themselves.

Writing on the subject of dewponds on the Sussex Downs, Jefferies - whose conclusions on the question of water-supply are similar to those advanced by White - mentions the fact that a layer of soot was employed by the builders to prevent worms or grubs from boring into the clay, and thus letting water into the chalky soil beneath. Later dewpond makers observed the same principle, only substituting lime for soot. Jefferies then confidently asserts that when once filled with water during wet weather the supply is afterwards kept up by the condensation of mist, dew and the early morning vapours so often to be seen on the Downs.

But if, as Mr. Martin has pointed out, the latest theory of the formation of dew - i.e. that it " comes from the moisture which rises out of the earth with the radiation of heat, and that it is this which is precipitated when the air into which it passes has been so reduced in temperature as to be unable to hold it as aqueous vapour " - be the correct one, the suggestion of certain theorists that dewponds are fed and filled by dew is at once disposed of, " since the acquisition of dew could only then be obtained at the expense of itself by earlier evaporation."

The Rev. H. P. Slade boldly asserts that term " dewpond " is a misnomer, and suggests that (on the supposition that it is upon rain and not dew, that these hill-ponds have to rely), the name be altered to some such title as " artificial rain-pond." But it is safe to say that custom and popular prejudice will, in this matter, continue to have their own way, and the picturesque title " dewpond " will be applied to the familiar sheep-pond of the Downs to the end of the chapter.

Mr. Slade, who has made a long and careful scientific study of the construction of dewponds and their thermo-dynamics, has favoured me with a considerable number of notes on the subject which, I regret to say, limits of space will not allow me to embody at length. Briefly, however, it may be stated that as a result of his observations and experiments conducted in Oxfordshire and elsewhere, Mr. Slade proved to his own satisfaction that " dew plays so unimportant a part in filling the ponds as to deserve little notice," and that, from the fact that mountains and hills attract the clouds and help to condense their vapour into rain, " the primary cause of the ponds' supply is the rainfall." As elevated tracts receive the largest quantity of rain, height above sea-level is, in this respect, advantageous. The slopes of the Downs were found greatly to increase the value of a downfall of rain, which, in some cases, was, from this fact, double. When the water of a pond is nearly exhausted, and a downpour ensues, the rain in time deluges the slopes and converts them into channels by which the rain is drained down into the pond. Only during winter does Mr. Slade admit the value of dew in assisting to supply the pond; and then, he argues, it is not on account of the volume of water contributed by the dew itself, but by reason of the fact that at that time of the year the power of the slopes is augmented, since in the winter months they are constantly more or less saturated.

In constructing a dewpond on scientific lines, Mr. Slade advises that dry straw or sawdust be placed under the puddled clay. First, a coating of dry straw should be laid, then one of good, well-puddled clay, twelve inches thick ' with which a little lime has been mixed; then, finally, 'closely strewn stones or rubble to the depth of six inches. It is essential that the margin of the straw be effectually protected by the clay, as, if wet, the straw ceases to act as a non-conductor of heat. It is also to be noted that if rushes are allowed to grow through the clay bottom the roots cause leakage, and the pond, unless speedily repaired, is ruined.

A pond built on this plan should be placed on an elevation, and care should be taken not to allow surface water to run into it by means of runnels, as these in time fill up the pond with sediment. [As I have noted above in the case of the latest made ponds on the Glynde Estate, runnels form an important feature of the construction, the ponds being protected from deposits of sediment by means of filters.] Corrugated iron should be placed over the rubble slopes, to avoid loss of rainfall from slope saturation. Concrete, asphalt, cement and bricks should be avoided, unless covered up and protected from the heat of the sun in summer and from frost in winter. On the other hand, Mr. Pickard is of opinion that it is not necessary to protect the pond from frost, provided that the cement is thoroughly set before the frost begins; though he admits that, if it is built upon a slope and part of it rests upon " made " ground, there is a danger of the frost getting under it.

The only conclusions at which I have been able to arrive from the conflicting opinions of the authorities quoted, are that dew contributes little of appreciable value to the water of these Downland ponds ; that, in the case of those ponds which are situated on the lower slopes of the hills, or at the bottom of the valleys, by far the greater quantity of water comes from surface drainage ; and that in the case of the ponds on the summits the supply of water comes from falling rain, mists, and the condensation of the heavy fogs, which are familiar to all who know the Downs. The material dug from the centre of this type of hill-pond, being piled round the circumference, gives the depression a very large collecting area, and when this is frozen nearly every drop of rain that falls over the excavation before a thaw allows it to soak into the earth, goes to fill the pond, and this remark applies, similarly, to snow. But the question of water-supply to Downland dewponds, of their proper scientific construction, of their history and evolution, remains a fascinating one, and should prove a profitable field of investigation for some future inquirer.

1 Since this chapter was written a correspondent reminds me that there are two ponds now existing on Chanctonbury, the smaller one having been made by a Findon man about fifty years ago, and that there is no evidence concerning the origin of the larger one. My correspondent suggests that Mr. Morgan may have mistaken the smaller pond for the larger, as the former is closer to the old coach track. I may add that Mr. Morgan's statement, which I have quoted above, was taken from a leaflet which was issued by that gentleman, and which indicates, clearly enough, that the writer refers to the larger of the two ponds.

Arthur Becket - The Spirit of the Downs - Publisher Methuen, 1909


Home ] Up ]

Copyright 2002-6  Martin Snow and contributors as noted. All rights reserved.
Last modified: February 25, 2006