Dew Ponds
Dew pond is the name applied to certain shallow saucer-shaped basins which usually contain a supply of water even during prolonged drouths when ordinary ponds at lower levels dry up...
by Manpreet
Illustrations by Amarjeet Malik

Dew pond is the name applied to certain shallow saucer-shaped basins which usually contain a supply of water even during prolonged drouths when ordinary ponds at lower levels dry up. The mode of replenishment is somewhat mysterious because the most successful dew ponds are situated on the highest points of the chalk downs of southern England, where the soil is extremely porous, where there are no springs, where evaporation proceeds more rapidly than in the valleys, and where many cattle and sheep consume large quantities of the water daily. They received their common name from the belief that they are replenished chiefly by the deposit of dew on the surface of the water, a belief which probably arose from the fact that during the hottest, weather the vegetation in the vicinity of such ponds is often thickly covered with dew after nightfall. Scientists who have investigated the subject report that dew has little if anything to do with the mysterious replenishment of the ponds during drouths. It is believed that they receive water from downland fogs and mists from the sea, in addition, of course, to the regular supply from rain. That fog or mist is the source of some water is confirmed by the fact that the ponds contain considerable quantities of sodium chloride and other salts. This theory would also explain why those ponds on the highest points of the chalk downs are usually the last to dry up during a drouth. Apparently the ponds have the power of attracting water from the mists, fogs, and low clouds, and accordingly in some sections of England they are known as mist ponds, fog ponds and cloud ponds. It is commonly believed by the people on the downs that dew ponds were made in prehistoric times. Certainly some of the ponds still in existence date back many generations. Even at the present time they are constructed along certain traditional lines. The essence of the typical dew pond is its waterproof bottom, which is made by puddling clay tempered with chalk or lime. Sometimes layers of straw are elaborately laid beneath the puddled clay bottom, but the purpose and value of this feature is a question of dispute among the pond builders themselves. Usually a layer of loose chalk rubble is placed over the clay to prevent cattle from perforating the bottom with their hoofs. As a rule the pond is filled the first time by artificial means.