Authority as defined in 1964). Tides The estuary just east of the Tideway has a tidal range of 4 metres. Winds excluded, it moves at in bi-monthly spring tides. Economy Shipping The estuary is one of the largest of 170 such inlets on the coast of Great Britain. It constitutes a major shipping route, with thousands of movements each year, including: large oil tankers, container ships, bulk carriers (of loose materials/liquids), and roll-on/roll-off (ro-ro) ferries. It is the accessway for the Port of London (including London Gateway, associated Tilbury and Purfleet) and the Medway Ports of Sheerness, Chatham and Thamesport. The traditional Thames sailing barge worked in this area, designed to be suitable for the shallow waters in the smaller ports. Wind farms A 2000s-decade-built wind farm is 8.5 km north of Herne Bay, Kent, on a shoal south-west of Kentish Knock. It is 30 wind turbines generating typically 82.4MW of electricity. The much larger 630 MW London Array was inaugurated in 2013. Greater Thames Estuary The term Greater Thames Estuary applies to the coast and the low-lying lands bordering the estuary. These are characterised by the presence of mudflats, low-lying open beaches, and salt marshes, namely the North Kent Marshes and the Essex Marshes. Man-made embankments are backed by reclaimed wetland grazing areas, but rising sea levels may make it necessary briefly to flood some of that land at spring tides, to take the pressure off the defences and main watercourses. There are many smaller estuaries in Essex, including the rivers Colne, Blackwater and Crouch. Small coastal villages depend on an economy of fishing, boat-building, and yachting. The Isle of Sheppey, the Isle of Grain, Canvey Island, Two Tree Island, Havengore Island, New England Island, Rushley Island, Potton Island, Foulness Island and Mersea Island are part of the coastline. Where higher land reaches the coast, there are some larger settlements, such as Clacton-on-Sea to the north in Essex, Herne Bay, Kent, and the Southend-on-Sea area within the narrower part of the estuary. 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 Thames Estuary 2050 Growth Commission report published in June 2018 identified the economic potential of the region. In 2020 the Thames Estuary Growth Board was appointed, led by government-appointed Envoy Kate Willard OBE, to unlock the potential of the UK's number