River Taff - wikipedia River Taff Not to be confused with River Taf. This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( April 2009 ) River Taff ( Afon Taf ) River The Taff flowing through Llandaff. Llandaff Rowing Club and a large weir lie in the distance Country Wales County Merthyr Tydfil, Rhondda Cynon Taf, Cardiff Tributaries - left Afon Bargoed Taf - right Afon Cynon, Nant Clydach, River Rhondda Settlements Merthyr Tydfil, Treharris, Pontypridd, Cardiff Source - location Cefn - coed - y - cymmer, Merthyr Tydfil, Wales Length 64.0 km ( 40 mi ) Part of the River Taff, running through Cardiff A weir and footbridge ( Blackweir Bridge ) over the River Taff ( Cardiff ) Waterfall on the Taff near Pontypridd The River Taff ( Welsh : Afon Taf ) is a river in Wales. It rises as two rivers in the Brecon Beacons -- the Taf Fechan ( Little Taff ) and the Taf Fawr ( Big Taff ) -- before joining to form the Taff north of Merthyr Tydfil. The river supports a number of migratory fish, including salmon, sea trout, and eel. Contents 1 Course 1.1 Diversion in Cardiff 2 Taf Fawr 3 Taf Fechan 4 Tributaries 4.1 Nant Ffrwd 4.2 Nant Morlais and Nant Rhydycar 4.3 Taff Bargoed, Cynon, Nant Clydach and Rhondda 5 Mouth of the Taff 6 `` Taffy '' 7 See also 8 References 9 External links Course From its confluence at Cefn - coed - y - cymmer, the river flows south, passing several towns. It picks up a few tributaries, such as the River Cynon, River Rhondda, Bargoed Taf and Nant Clydach. It flows through Pontypridd and through to Taff 's Well, the site of Wales ' only thermal spring. It flows underneath the M4 Motorway, before turning southeastward and flowing through the Cardiff suburbs of Radyr, Whitchurch, Llandaff, Pontcanna, the city centre and Grangetown, before emptying into Cardiff Bay, near to the mouth of the River Ely. Diversion in Cardiff Main article : Cardiff Central railway station In the early 1840s the South Wales Railway was trying to find a suitable site for a railway station, but the area that is now Cardiff Central railway station was prone to flooding. At this point the main route of the Taff was around Cardiff Castle and down what is now Westgate Street, with the lands where Cardiff Arms Park and the Millennium Stadium are now sited tidal flats which were prone to flood. It was Isambard Kingdom Brunel 's solution to divert the Taff to the west, creating a larger and safer site for the station. The station was opened by the South Wales Railway in 1850. Taf Fawr The Taf Fawr rises below Corn Du, south - west of Pen y Fan and flows south through Beacons Reservoir, Cantref Reservoir and Llwyn - on Reservoir. Taf Fechan The Taf Fechan rises immediately to the south of Pen y Fan and runs southwards through the two Neuadd Reservoirs, Pentwyn Reservoir and finally Pontsticill reservoir before descending into a wooded gorge known as the Blue Pool and flowing south - westwards around the hamlet of Trefechan. To the south of Cefn - coed - y - cymmer, the Taf Fechan and Taf Fawr merge at the wooded confluence that gives Cefn - coed - y - cymmer its name. Pontsticill Water Treatment Works The river holds a large population of wild brown trout, many of which were killed in 2006 when a large quantity of aluminium sulphate was flushed into the river from the Pontsticill Water Treatment Works, which United Utilities operate on behalf of Dwr Cymru Welsh Water. The pollution turned the water white for at least 5km downstream of the works and killed approximately 23,000 fish, including wild brown trout, bullheads, stickleback and pike, and a large number of invertebrates. Environment Agency Wales estimated that the river would take six to twelve years to recover. The trout population had resumed breeding by 2009. Tributaries Nant Ffrwd Underneath the Cefn Coed Viaduct, the Nant Ffrwd, a tributary that runs eastward in a deep wooded gorge before flowing into the Taf Fawr above the confluence with the Taf Fechan, emerges into the river from a deep, narrow gorge. Nant Morlais and Nant Rhydycar The Taff continues south through the centre of Merthyr Tydfil, where it is joined by the Nant Morlais which emerges at Abermorlais from a culvert in the east bank. Just south of Merthyr weir, the Nant Rhydycar joins. Taff Bargoed, Cynon, Nant Clydach and Rhondda South of Merthyr, the Taff begins to meander its way between Pentrebach and Abercanaid and through Troed - y - rhiw, Merthyr Vale and Aberfan towards Quakers Yard. Here, the Taff Bargoed, Nant Mafon and then down into Abercynon in the Cynon Valley where the Afon Cynon merge with the Taff and, slightly further downstream the Nant Clydach joins. At Pontypridd it is joined by the Afon Rhondda. From Pontypridd, it runs roughly south, through Taff 's Well and Radyr, before arriving at the northern boundary of the city of Cardiff in Llandaff. Mouth of the Taff Frozen river alongside the Millennium Stadium in Cardiff ( December 2010 ) In Cardiff, the natural course of the river was changed during the 19th century ; from Cardiff Castle it now follows an artificial riverbed west of where it previously flowed, now following a path through Bute Park and next to the Cardiff Arms Park and the former National Stadium, now the Millennium Stadium, and into Cardiff Bay, which has now become an artificial lake due to the construction of a barrage across the mouth of this river and the River Ely. It then flows out into the Severn Estuary. `` Taffy '' The derogatory term `` Taffy '' for a Welsh person is sometimes erroneously stated to have originated with the river. This may have given rise to a colloquial usage of the term by Cardiff residents for people from the Taff 's northern reaches ( Mid Glamorgan Valleys ). The name actually originates as a corruption of the name Dafydd, with the Oxford English Dictionary describing the origin as `` representing a supposed Welsh pronunciation of the given name Davy or David ( Welsh Dafydd ) ''. It was common for people in times of war to dehumanise an enemy by ascribing a singular name to them all. It is therefore an equivalent of other historic English pejoratives such as Paddy and Jock. The term is a common nickname within the British army, with individual Welsh troops, units and especially the Welsh Guards sometimes referred to as `` The Taffs ''. However, it has been reported that the guardsmen themselves never use that term. See also Pont - y - Cafnau, world 's earliest surviving iron railway bridge References Jump up ^ `` Cardiff Arms Park, A short History - The Creation of the Arms Park ''. Cardiff Council. Archived from the original on 2012 - 10 - 15. Retrieved 2008 - 05 - 22. Jump up ^ River Taff Corridor Action Plan April 2007, page 7 Jump up ^ `` Taffy, n. 2 ''. Oxford English Dictionary. Retrieved 2013 - 04 - 02. Jump up ^ Beard, Mary ( 11 January 2009 ). `` A Don 's Life ''. Jump up ^ Harnden, Toby ( 2011 ). Dead men risen : the Welsh Guards and the real story of Britain 's war in Afghanistan. London : Quercus. ISBN 978 - 1849164238., mentioned in `` Dead Men Risen : How do the Welsh Guards keep up with the Joneses ? ''. The Daily Telegraph. 21 March 2011. Archived from the original on 21 January 2016. External links Glamorgan - Gwent Archaeological Trust Merthyr Tydfil Features Coordinates : 51 ° 28 ′ N 3 ° 11 ′ W ﻿ / ﻿ 51.467 ° N 3.183 ° W ﻿ / 51.467 ; - 3.183 Rhondda Cynon Taf Rhondda Cynon Taf County Borough Council Communities Aberaman Abercynon Aberdare Cwm Clydach Cwmbach Cymmer Ferndale Gilfach Goch Hirwaun Llanharan Llanharry Llantrisant Llantwit Fardre Llwydcoed Llwynypïa Maerdy Mountain Ash Penrhiwceiber Pentre Pen - y - graig Penywaun Pont - y - clun Pontypridd Porth Rhigos Taff 's Well Tonypandy Tonyrefail Trealaw Trehafod Treherbert Treorchy Tylorstown Ynyshir Ynysybwl and Coed y Cwm Ystrad Towns and villages Aberaman Abercwmboi Abercynon Aberdare Abernant Beddau Blaenclydach Blaencwm Blaenllechau Blaenrhondda Britannia Bryncae Bryngolau Brynna Brynsadler Brynteg Buarth - y - Capel Bwllfa Dare Caegarw Carnetown Castell y Mwnws Castellau Cefn Rhigos Cefnpennar Church Village Cilfynydd Clydach Vale Coed - Ely Coedpenmaen Coed - y - Cwm Collena Croesbychan Cross Inn Cwm - Hwnt Cwmaman Cwmbach Cwmdare Cwmparc Cwmpennar Cymmer Dinas Rhondda Dolau Edmondstown Efail Isaf Ferndale Fernhill Foundry Town Gadlys Garden City Gelli Gilfach Goch Glan Y - Ffordd Glan - Y - Llyn Glenboi Glyncoch Glynfach Glynhafod Glyntaff Godreaman Graig Graigwen Groes - faen Hawthorn Hendreforgan Hirwaun Hopkinstown Ilan Llanharan Llanharry Llanilid Llantrisant Llantwit Fardre Llwydcoed Llwyncelyn Llwynypia Maerdy Maesycoed Miskin, Mountain Ash Miskin, Pontyclun Mountain Ash Mwyndy Nantgarw Newtown Pantygraigwen Penderyn Penpisgah Penrhiwceiber Penrhiwfer Penrhys Pentre Pentrebach Pen - y - coedcae Penygraig Penygraigwen Penywaun Perthcelyn Pontcynon Pontsionnorton Pontyclun Pontygwaith Pontypridd Porth Pwllgwaun Rhigos Rhiw Ddar Rhiwsaeson Rhydyfelin Robertstown Roberttown Stanleytown Taffs Well Talbot Green Talygarn Thomastown Ton Pentre Tonteg Tonypandy Tonyrefail Trallwn Trealaw Trebanog Trecynon Treforest Trehafod Treherbert Trenant Treorchy Ty Fry Ty - Rhiw Tyla Garw Tylcha Tylorstown Tynewydd Tynybryn Tyn - y - nant Tyntetown Upper Boat Upper Church Village Wattstown Williamstown Ynysangharad Ynysboeth Ynysddu Ynyshir Ynysmaerdy Ynyswen Ynysybwl Ystrad Rhondda Education Aberdare Girls ' School Aberdare High School Blaengwawr Comprehensive School Bryn Celynnog Comprehensive School Coleg y Cymoedd Hawthorn High School Mountain Ash Comprehensive School Pontypridd High School St. John the Baptist School Treorchy Comprehensive School University of South Wales Y Pant School Ysgol Gyfun Cymer Rhondda Ysgol Gyfun Garth Olwg Ysgol Gyfun Llanhari Ysgol Gyfun Rhydywaun Rivers Afon Clun Afon Sychryd River Cynon River Ely River Rhondda River Taff Topic lists Parliamentary constituencies Places SSSIs Grade I listed buildings Grade II * listed buildings High Sheriffs Lord Lieutenants Museums Major infrastructure M4 motorway category Retrieved from `` https://en.wikipedia.org/w/index.php?title=River_Taff&oldid=799664252 '' Categories : River Taff Rivers of Cardiff Rivers of Merthyr Tydfil County Borough Rivers of Rhondda Cynon Taf Hidden categories : Articles needing additional references from April 2009 All articles needing additional references Geobox usage tracking for river type Articles containing Welsh - language text All articles with unsourced statements Articles with unsourced statements from November 2016 Coordinates on Wikidata Talk Contents About Wikipedia Boarisch Brezhoneg Català Cebuano Čeština Cymraeg Deutsch Eesti Español Euskara Français Gaeilge Italiano Kiswahili Lietuvių Nederlands Polski Slovenčina Српски / srpski Srpskohrvatski / српскохрватски Svenska Edit links This page was last edited on 9 September 2017, at 02 : 59. 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Question: where does the river taff start and finish
Answer: Cefn-coed-y-cymmer