Thames Estuary The new airport would be built on a man-made island in the estuary north of Minster-in-Sheppey There is also some discussion about the need for a Lower Thames Crossing in order to alleviate traffic congestion at Dartford. The Thames Estuary is the focal part of the 21st-century toponym, the "Thames Gateway", designated as one of the principal development areas in Southern England. The appellation Greater Thames Estuary applies to the coast and the low-lying lands bordering the estuary itself. These are characterised by the presence of mudflats, low-lying open beaches and salt marshes, namely the North Kent Marshes and the
Yalu River its length. Most of the river freezes during winter and can be crossed on foot. The depth of the Yalu River varies from some of the more shallow parts on the eastern side in Hyesan (1 m) to the deeper parts of the river near the Yellow Sea (2.5 m). The estuary is the site of the Amrok River estuary Important Bird Area, identified as such by BirdLife International. About 205 islands are on the Yalu. A 1962 border treaty between North Korea and China split the islands according to which ethnic group was living on each island. North Korea