Isle of Sheppey Yantlet Creek at the Isle of Grain to the west, it was occasionally used in ancient times by shipping to and from ports such as Chatham and London to reduce exposure to bad weather in the Thames Estuary or North Sea. The Kingsferry Bridge was first built in 1860, thus eliminating the need for ferries. Over time, there have been four bridges built over the Swale at this point. All bridges had to allow sufficient clearance for shipping heading to the commercial docks at Ridham: On 5 September 2013, fog caused a 130 vehicle pile-up on the Sheppey Crossing bridge
Estuary river valleys are also known as coastal plain estuaries. In places where the sea level is rising relative to the land, sea water progressively penetrates into river valleys and the topography of the estuary remains similar to that of a river valley. This is the most common type of estuary in temperate climates. Well-studied estuaries include the Severn Estuary in the United Kingdom and the Ems Dollard along the Dutch-German border. The width-to-depth ratio of these estuaries is typically large, appearing wedge-shaped (in cross-section) in the inner part and broadening and deepening seaward. Water depths rarely exceed . Examples of