Editing River Thames (section)

====Non-tidal section====
{{Main|Locks and weirs on the River Thames}}
[[File:jubilee weir.jpg|thumb|The [[Jubilee River]] at [[Slough Weir]]]]
[[File:St John's Lock and Lechlade in background.JPG|thumb|upright|St John's Lock, near [[Lechlade]]]]
[[File:River thames oxford.jpg|thumb|right|The River Thames in [[Oxford]]]]

Brooks, canals and rivers, within an area of {{cvt|3842|sqmi|km2|0}},<ref name="CEH">{{cite web |url=http://www.ceh.ac.uk/data/nrfa/nhmp/annual_review/feature_articles/Flow_Gauging_on_River_Thames_100_Years.pdf |title=Flow Gauging on the River Thames – The First 100 Years |year=1983|page=33 |publisher=Hydrological Data |access-date=9 November 2011 |archive-date=Dec 2, 2011 |archive-url=https://web.archive.org/web/20111202170904/http://www.ceh.ac.uk/data/nrfa/nhmp/annual_review/feature_articles/Flow_Gauging_on_River_Thames_100_Years.pdf |url-status=dead }}</ref> combine to form 38 main tributaries feeding the Thames between its source and [[Teddington Lock]]. This is the usual [[tidal limit]]; however, high spring tides can raise the head water level in the reach above Teddington and can occasionally reverse the river flow for a short time. In these circumstances, tidal effects can be observed upstream to the next lock beside [[Molesey Lock|Molesey weir]],<ref name="CEH"/> which is visible from the towpath and [[Hampton Court Bridge|bridge]] beside [[Hampton Court Palace]]. Before Teddington Lock was built in 1810–12, the river was tidal at peak spring tides as far as [[Staines upon Thames]].

In descending order, non-related tributaries of the non-tidal Thames, with river status, are the [[River Churn|Churn]], [[River Leach|Leach]], [[River Cole, Wiltshire|Cole]], [[River Ray, Wiltshire|Ray]], [[River Coln|Coln]], [[River Windrush|Windrush]], [[River Evenlode|Evenlode]], [[River Cherwell|Cherwell]], [[River Ock|Ock]], [[River Thame|Thame]], [[River Pang|Pang]], [[River Kennet|Kennet]], [[River Loddon|Loddon]], [[River Colne, Hertfordshire|Colne]], [[River Wey|Wey]] and [[River Mole, Surrey|Mole]]. In addition, there are occasional backwaters and artificial cuts that form islands, [[distributary|distributaries]] (most numerous in the case of the [[River Colne, Hertfordshire|Colne]]), and man-made distributaries such as the [[Longford River]]. Three canals intersect this stretch: the [[Oxford Canal]], [[Kennet and Avon Canal]] and [[Wey Navigation]].

Its longest artificial secondary channel (cut), the [[Jubilee River]], was built between Maidenhead and Windsor for flood relief and completed in 2002.<ref>{{cite web |url=http://www.ukriversguidebook.co.uk/seengland/thamesjubilee.htm |title=UK Rivers Guide Book Guide to the River Thames – Jubilee River |publisher=Ukriversguidebook.co.uk |date=23 January 2011 |access-date=2 April 2012 |archive-date=3 May 2010 |archive-url=https://web.archive.org/web/20100503110907/http://www.ukriversguidebook.co.uk/seengland/thamesjubilee.htm |url-status=dead}}</ref><ref>{{cite web |url=http://www.environment-agency.gov.uk/commondata/acrobat/jubileerivermap_1200567.pdf |archive-url=https://web.archive.org/web/20070930152507/http://www.environment-agency.gov.uk/commondata/acrobat/jubileerivermap_1200567.pdf |archive-date=30 September 2007 |title=Environment Agency – A map indicating the location and route of the Jubilee River |date=30 September 2007 |access-date=2 April 2012}}</ref>

The non-tidal section of the river is managed by the [[Environment Agency]], which is responsible for managing the flow of water to help prevent and mitigate flooding, and providing for navigation: the volume and speed of water downstream is managed by adjusting the sluices at each of the weirs and, at peak high water, levels are generally dissipated over preferred flood plains adjacent to the river. Occasionally, flooding of inhabited areas is unavoidable and the agency issues flood warnings. Due to stiff penalties applicable on the non-tidal river, which is a drinking water source before treatment, [[sanitary sewer overflow]] from the many [[sewage treatment plant]]s covering the upper Thames basin should be rare in the non-tidal Thames. However, storm sewage overflows are still common in almost all the main tributaries of the Thames<ref>{{cite web |url=https://www.theguardian.com/environment/2020/jul/01/water-firms-raw-sewage-england-rivers |title=Exclusive: water firms discharged raw sewage into England's rivers 200,000 times in 2019 |work=The Guardian |access-date=4 August 2020 |date=1 July 2020 |archive-date=27 August 2020 |archive-url=https://web.archive.org/web/20200827085619/https://www.theguardian.com/environment/2020/jul/01/water-firms-raw-sewage-england-rivers |url-status=live}}</ref><ref>{{cite web |url=https://www.arcgis.com/apps/webappviewer/index.html?id=a6dd42e3bc264fc28134c64c00db4a5b&extent=146436.9576%2C27590.8012%2C854242.0922%2C563326.0668%2C27700 |publisher=The Rivers TRust |access-date=4 August 2020 |title=Is my river fit to play in? |archive-date=5 August 2020 |archive-url=https://web.archive.org/web/20200805024256/https://www.arcgis.com/apps/webappviewer/index.html?id=a6dd42e3bc264fc28134c64c00db4a5b&extent=146436.9576%2C27590.8012%2C854242.0922%2C563326.0668%2C27700 |url-status=live}}</ref> despite claims by Thames Water to the contrary.<ref>{{cite web |url=http://www.thameswater.co.uk/tw/common/downloads/about%20us%20-%20corporate%20responsibility/annual-performance-report-2011-12.pdf |title=Report of the designated sewerage company for the entire Thames Basin and major supplier of London's water supply: Thames Water |access-date=20 November 2012 |archive-url=https://web.archive.org/web/20150131021304/http://www.thameswater.co.uk/tw/common/downloads/about%20us%20-%20corporate%20responsibility/annual-performance-report-2011-12.pdf |archive-date=31 January 2015 |url-status=dead}}</ref>