The traditional Thames sailing barge worked in this area, designed to be suitable for the shallow waters in the smaller ports.
Human-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.
[8] 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 flowing through London is an archetypal, well-developed economy urban, upper river estuary with its sedimentary deposition restricted through manmade embankments and occasional dredging of parts.
Further east salinity increases and conditions become fully marine and the fish fauna resemble that of the adjacent North Sea, a spectrum of euryhaline and stenohaline types.
[16] Instead, coastal navigators and pilots relied on the use of transits (the alignment of prominent structures or natural features on land) for guidance.
In 1566 Trinity House of Deptford (which oversaw pilotage on the Thames) was empowered to 'make, erect and set up [...] beacons, marks and signs for the sea' (albeit at its own expense).
[16] In his coastal survey of 1682-93, Greenvile Collins records five buoys around the Narrows, just north of Reculver, on the southern approach to the Thames.
The Swin (the northern approach) was marked with buoys at the easternmost points of the Gunfleet, Middle and Buxey sands, and by beacons on the Whitaker, Shoe and Blacktail spits.
[18] The coastwise approach from the north was aided by the establishment of the Sunk lightvessel in 1802 'to mark the north-east entrance to East Swin, and to guide vessels round Long Sand'.
In 1851 two more screw-pile lighthouses were built further upriver, on the northern foreshore of Sea Reach: at Mucking and on the Chapman sands (just off Canvey Island).
[21] In 1885 the beacons at Broadness and Stoneness were replaced with iron-frame experimental lighthouses, each lit by a novel system which would allow the light to function unattended (except for a twice-weekly visit by a boatman for cleaning and maintenance).
[22] At the same time Trinity House began experimenting with the application of lamps to buoys, using Pintsch's oil-gas system, beginning with three in the Thames Estuary (East Oaze, Ovens and Sheerness Middle); the experiment was deemed a success and subsequently further buoys and beacons were lit by Trinity House using the same system, in the Estuary and beyond.
[22] Today the Port of London Authority's Thames Navigation Service (established in 1959) is responsible for buoyage, beaconage and bridge lights on the Tideway.