Notes from the boundary: Peter Hart: Dew ponds in the Parish of Stone–cum

I have always known that dew ponds are a feature of some parts of the British countryside, and assumed them to be natural formations of some kind. But quite how minute drops of water could fill and viably sustain the level of a pond has always been beyond my imagination. The Shorter Oxford Dictionary’s description of dew gives an illustrative quote from Wordsworth: “The dew was falling fast, the stars begin to blink.” But dew does not fall like rain. It does not fall at all: it results from condensation, formed by the contrast in temperature as “out of night earth rolls her dewy side”; but dew will not form unless the temperature contrast is sufficient. And how often does that happen?

Well, dew ponds are neither natural nor kept full by ‘dew–water’. They are man–made, and were created as circular ponds on high ground for the watering of oxen, cattle, and sheep. This mostly on the southern chalk downlands where the rain permeates the ground, and meets no resistance from clay or rock (there are no streams in the Chilterns). But only last week did I realise that the round ponds I had seen over decades of walking in the country were (in many cases) dew ponds. Most are now rich ecological sites, surrounded by reeds, rushes, wild flowers, and trees, and I imagine that livestock must now be watered from troughs, because the dew ponds are dense and undisturbed. Some are in the midst of wheat fields, and farmers seem perfectly happy to leave them as they are.

The Wikipedia definition of a dew pond includes the following passage:

A method of constructing the base layer using chalk puddle was described in The Field 14 December 1907. A Sussex farmer born in 1850 tells how he and his forefathers made dew ponds:

The requisite hole having been excavated, the chalk was laid down layer by layer, while a team of oxen harnessed to a heavy broad-wheeled cart was drawn round and round the cup shaped hole to grind the chalk to powder. Water was then thrown over the latter as work progressed, and after nearly a day of this process, the resultant mass of puddled chalk, which had been reduced to the consistency of thick cream, was smoothed out with the back of a shovel from the centre, the surface being left at last as smooth and even as a sheet of glass. A few days later, in the absence of frost or heavy rain, the chalk had become as hard as cement, and would stand for years without letting water through. This old method of making dew ponds seems to have died out when the oxen disappeared from the Sussex hills, but it is evident that the older ponds, many of which have stood for scores of years practically without repair, are still more watertight than most modern ones in which Portland cement has been employed.

Martin, Edward Alfred (1915). Dew-ponds: history, observation, and experiment. London: Werner Laurie.

There is an irony in the use of chalk on chalk here. And what a fine piece of descriptive writing this is!

The following photographs were taken on a grey August day. I hope that they show that photography does not necessarily have to be practiced only on sunny days. But that is for you to judge! I like the square format available on my camera, which I haven’t had since I was a boy with a Voigtländer (the oldest name in the history of cameras).

The dew pond illustrated above and opposite is on the eastern side of the Isle of Oxney, in the Parish of Stone–cum–Ebony. There is no chalk in this area; but a good reason for creating dew ponds would have been the periodic flooding by sea water of the levels surrounding the isle. I do not know if chalk was imported to create these dew ponds, or if a different method was used. The soil of the Isle of Oxney is loam on a subsoil of (Hastings Beds) sandstone. There were two ponds in adjacent fields.

Looking at this pond makes me think what an excellent PhD could be written about it:

The ecology, biodiversity, and history of a dew pond on the Isle of Oxney

Well, why not? Infinitely more sensible than: Why Henry James was a failure as a playwright – such was the subject being researched by a student I met in the 1990s. I didn’t even know that James had written any plays...