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
Inner Tay Estuary Inner Tay Estuary The Inner Tay Estuary, the inner, western part of the Firth of Tay, stretching from the Tay Railway Bridge in the east to the Queen's Bridge over the River Tay in Perth and the bridge in Bridge of Earn on the River Earn. The estuary is one of the largest in eastern Scotland and is up to 2.5 km wide. The estuary consists primarily of inter-tidal sand and mud flats that extend seaward out to the main channel of the estuary, the majority of which lie on the northern shore. Landward of these are saltmarsh and "Phragmite"s