The Cambridge Arm is in fact the canalised lower part of the river Cam, which runs down from Dursley, through Cam and eventually into the G&S canal. It is barely 2 km long, but is quite a pretty little waterway. At one time it was navigable, but the way is currently blocked by the swing bridge at the entrance to the canal and the concrete bridge next to the water pumping station about halfway along. The upper limit of navigation was at Cambridge, where the river passes under the A38 in a low culvert.
The arm could easily be opened to navigation. The only significant obstacle is the concrete bridge halfway along, which it is said is to be replaced anyway in the near future. There is a reasonable depth of water along most of the arm, and the width is adequate for two narrowboats to pass in most places. A winding hole would need to be dug out near the top to accomodate boats longer than about 8 m.
There is a footpath running alongside the Arm from the A38, through the George's garden, and along as far as the junction with Wickster's Brook. At this point, it is feasible to walk almost all the way to the junction with the G&S although there is no right of way. The "official" footpath veers north, over Nebrow Hill (13 m) (is this the lowest hill graced with the name "Hill"?)and on towards Splatt Bridge at Frampton on Severn.