The Thames Estuary is the estuary in which the River Thames meets the waters of the North Sea.
It is not easy to define the limits of the estuary, although physically the head of Sea Reach, near Canvey Island on the Essex shore is probably the western boundary. The eastern boundary, as suggested in a Hydrological Survey of 1882-9, is a line drawn from North Foreland in Kent via the Kentish Knock lighthouse to Harwich in Essex. It is to here that the typical estuarine sandbanks extend. The estuary has the world's second largest tidal movement, where the water can rise by 4 metres moving at a speed of 8 miles per hour.-
