The river drains the Weald Moors a fenland area north of Telford, and also takes runoff from Newport and Lilleshall.

[1] The river is formed by the confluence of the Pipe Strine and the Wall Brook.

Beyond this point it passes the village of Crudgington, where it is bridged by the A442, it then joins the Tern.

The flow of the river was measured at an electromagnetic gauging station in its lower reaches at Crudgington between 1982 and 2009.

[2] The catchment to the station yielded an average flow of 0.67 cubic metres per second (24 cu ft/s).