Colne Brook
The Colne Brook is a distributary of the River Colne and a tributary of the River Thames. It marks the boundary between Buckinghamshire and Middlesex at its lowest stretch.
The Colne Brook branches of the River Colne at Uxbridge Moor and flows close by it until West Drayton. It then passes under the M25 motorway at the M4 motorway interchange and flows through the village of Colnbrook. South of Colnbrook it receives another feed from the River Colne by the Poyle Channel and runs between Horton and Wraysbury Reservoir, where it is diverted.
From the reservoir, the course of the brook runs close to the gravel pits at Wraysbury (which make up a Site of Special Scientific Interest) and then it runs into the River Thames at Hythe End, between the M25 Runnymede Bridge and Bell Weir Lock.