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
River Sheppey where it joins Whites River and then the River Brue near Westhay. The water quality is generally good; however, there have been some discharges from sewage treatment works in the area that can contribute to nutrient levels in rivers. Signs of nutrient enrichment are noticeable at times of low flow and the ecology of the Sheppey is adversely affected in its upper reaches. It would appear that the Sheppey was only so called in the late 19th century. Prior to then, if it was called anything, it was probably Doulting Water or the River Brae. The Sheppey has been used