Abbey River Tideway where there are two larger islands. It is much smaller than Canvey Island and the Isle of Sheppey and narrowly ahead of Andersey Island facing Abingdon-on-Thames, another market town with an abbey which had multiple medieval mills, another of note being Westminster Abbey, the island of which Thorney Island no longer exists. The outfall of the Abbey River is 400 m above Chertsey Bridge, into the weir pool of Chertsey Weir. The manmade strictly-considered "island" the bypass channel forms is outranked in size since the 2002 completion of the Jubilee River by the example containing Dorney and Eton, Berkshire.
Severn Estuary the line between Lavernock Point and Sand Point is the Bristol Channel, which in turn discharges into the Celtic Sea and the wider Atlantic Ocean. The islands of Steep Holm and Flat Holm are located close to that line, in the middle of the estuary. Sometimes the term "Severn Estuary" is used to include the tidal upstream stretch between Gloucester and Aust. During the highest tides on the upper reaches of this stretch, the rising water is funnelled up the estuary into the Severn bore, a self-reinforcing solitary wave that travels rapidly upstream against the river current. The tidal range