When the tide is out on the River Severn you can see Longney Sands.  There's a nice looped walk around which you can follow.

You can start at Longney School, and turn left towards Churchend.  On the left hand side there is a public footpath side and a gate which leads you down to the river, is quite hidden so have to look out for it. Then you can see how the path goes round and follow the walk.