Dew Ponds on the South Downs

This dew pond – as with the others along the Downs – has been here as long as the sheep, possibly dating back to medieval times. The chalky soil allows rainwater to drain straight down into the ground, so farmers dug circular troughs to catch water for their flocks. The base of the pond was usually lined with straw and puddled clay, which was wetted and beaten down to create an impermeable surface. A layer of burnt lime was used to stop worms breaking up the clay. It was once thought that the main source of water was the dew but the ponds simply catch rain. Sheep still graze in the neighbouring field.