The dry bed of the River Ebble, pictured in August
A winterbourne is a stream or river that is dry through the summer months, a special case of an intermittent stream. Winterbourne is a British term derived from the Old English winterburna ("winter stream"). A winterbourne is sometimes simply called a bourne, from the Anglo-Saxon word for a stream flowing from a spring, although this term can also be used for all-year water courses.[1] Winterbournes generally form in areas where there is chalk (or other porous rock) downland bordering clayvalleys or vales. When it rains, the porous chalk holds water in its aquifer, releasing the water at a steady rate. During dry seasons the water table may fall below the level of the stream's bed, causing it to dry out.
Exploitation of chalk aquifers as a domestic water source in Britain has had the effect of converting many streams and rivers into artificial winterbournes. This effect is controversial, and local campaigns have often been successful in reducing aquifer abstraction and reversing the effect. For an example, see the River Pang in Berkshire.
There is a winterbourne stream in a suburban area of Lewes, East Sussex. The area is also called Winterbourne. The stream runs from the foot of the South Downs through a park, a housing estate and a public garden, ending at the Railway Land Nature Reserve where it meets the River Ouse. It is a clear and verdant stream, much frequented by ducks. Another winterbourne stream is the River Lavant found In Chichester, West Sussex.
