The River Aldbourne is a pretty chalk stream, which in its upper reaches around the village of Aldbourne is a winterbourne, but nearer its confluence with the River Kennet flows all year round.
When ground water levels are high, the Aldbourne rises above the village which shares its name and flows through Preston and Ramsbury before joining the River Kennet near Knighton.
The Aldbourne has been subject to repeated pollution incidents caused by groundwater entering foul-water sewers causing them to overflow onto the streets and into the river. In 2010 Thames Water was fined by the Environment Agency for allowing repeated pollution incidents to occur. Thames Water has been working with the local ‘Drainage Improvement Group – ‘DIG’ to find a resolution to the problem. The most recent fish surveys on the Aldbourne were conducted in the early 1990s, and showed brown trout, grayling and pike. The assessment of ‘good ecological status’ was based on invertebrate surveys.