A dry valley is a valley found in either karst (limestone) or chalk terrain that no longer has a surface flow of water.
There are many examples of the latter along the North and South Downs in southern England. Notably the National Trust-owned Devil's Dyke near Brighton covers some 200 acres (0.81 km2) of downland scarp, and includes the deepest dry valley in the world - created when melting water eroded the chalk downland to the permafrost layer after the last ice age. The three-quarter mile long curved dry valley is around 700 feet (210 m) in height and attracts tourists with its views of Sussex, Hampshire and Kent.
Other examples include the Alkham Valley near Dover, and the Hartley Bottom and Fawkham valleys near Dartford in north Kent.
There are two theories as to how they were made, the first that the water table was once much higher, while the other is that during the ice age the area had tundra like conditions. The normally permeable chalk would have been made impervious by permafrost, thus allowing rivers to flow without carving into it. Today these valleys don't have any rivers because water sinks through into the limestone and flows underground in caverns.
There are many examples in the Peak District and the Yorkshire Wolds. A notable example is the valley of the River Manifold which is dry, except in spate, from Wetton south for several miles.
Famous quotes containing the words dry and/or valley:
“Since time immemorial, one the dry earth, scraped to the bone, of this immeasurable country, a few men travelled ceaselessly, they owned nothing, but they served no one, free and wretched lords in a strange kingdom. Janine did not know why this idea filled her with a sadness so soft and so vast that she closed her eyes. She only knew that this kingdom, which had always been promised to her would never be her, never again, except at this moment.”
—Albert Camus 1013–1960, French-Algerian novelist, dramatist, philosopher. Janine in Algeria, in The Fall, p. 27, Gallimard (9157)
“How old the world is! I walk between two eternities.... What is my fleeting existence in comparison with that decaying rock, that valley digging its channel ever deeper, that forest that is tottering and those great masses above my head about to fall? I see the marble of tombs crumbling into dust; and yet I don’t want to die!”
—Denis Diderot (1713–1784)