Editing River Thames (section)

====Tidal section====
{{Main|Tideway}}
[[File:London Stone, Staines 028.jpg|upright|thumb|[[London Stone (riparian)|London Stone]] at Staines, built in 1285 marked the customs limit of the Thames and the [[City of London]]'s jurisdiction.]]
[[File:Thames tide.jpg|thumb|Waterstand of Thames at low tide (left) and high tide (right) in comparison at Blackfriars Bridge in London]]
Below Teddington Lock (about {{cvt|55|mi|km|0|disp=or}} upstream of the Thames Estuary), the river is subject to [[tide|tidal activity]] from the [[North Sea]]. Before the lock was installed, the river was tidal as far as Staines, about {{cvt|16|mi|km}} upstream.<ref>{{cite web |url=http://www.visitthames.co.uk/text/106/free_fishing.html |title=River Thames Free Fishing |publisher=River Thames Alliance |access-date=10 June 2010 |archive-date=29 November 2010 |archive-url=https://web.archive.org/web/20101129220916/http://visitthames.co.uk/text/106/free_fishing.html |url-status=live}}</ref> London, capital of [[Roman Britain]], was established on two hills, now known as [[Cornhill, London|Cornhill]] and [[Ludgate Hill]]. These provided a firm base for a trading centre at the lowest possible point on the Thames.<ref>Peter Ackroyd ''London:The Biography'' Vintage 2001</ref>

A river crossing was built at the site of [[London Bridge]]. London Bridge is now used as the basis for published tide tables giving the times of [[tide|high tide]]. High tide reaches Putney about 30 minutes later than London Bridge, and Teddington about an hour later. The [[tidal reach|tidal stretch]] of the river is known as "the [[Tideway]]". Tide tables are published by the [[Port of London Authority]] and are available online.{{cn|date=March 2025}}

The principal [[tributaries of the River Thames]] on the Tideway include the rivers [[River Crane, London|Crane]], [[River Brent|Brent]], [[River Wandle|Wandle]], [[River Ravensbourne|Ravensbourne]] (the final part of which is called [[Deptford Creek]]), [[River Lea|Lea]] (the final part of which is called [[Bow Creek (London)|Bow Creek]]), [[River Roding|Roding]] (Barking Creek), [[River Darent|Darent]] and [[River Ingrebourne|Ingrebourne]]. In London, the water is slightly [[brackish water|brackish]] with sea salt, being a mix of sea and fresh water.

[[File:06 2023 Thames Barrier IMG 7506.jpg|thumb|The [[Thames Barrier]] provides protection against floods.]]
This part of the river is managed by the [[Port of London Authority]]. The flood threat here comes from high tides and strong winds from the North Sea, and the Thames Barrier was built in the 1980s to protect London from this risk.

[[The Nore]] is the [[sandbank]] that marks the mouth of the [[Thames Estuary]], where the outflow from the Thames meets the [[North Sea]]. It is roughly halfway between [[River Roach#The tidal river|Havengore Creek]] in Essex and Warden Point on the [[Isle of Sheppey]] in Kent. Until 1964 it marked the seaward limit of the Port of London Authority. As the sandbank was a major hazard for shipping coming in and out of London, in 1732 it received the world's first [[lightvessel|lightship]]. This became a major landmark, and was used as an assembly point for shipping. Today it is marked by Sea Reach No. 1 Buoy.<ref name=PortCities>{{Cite web |url=http://www.portcities.org.uk/london/server/show/nav.001008 |archive-url=https://web.archive.org/web/20071229125347/http://www.portcities.org.uk/london/server/show/nav.001008 |url-status=dead |title=PortCities London |archive-date=29 December 2007}}</ref>