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|River Taff (Afon Taf)|
|County||Merthyr Tydfil, Rhondda Cynon Taf, Cardiff|
|- left||Afon Bargoed Taf|
|- right||Afon Cynon, River Rhondda|
|Settlements||Merthyr Tydfil, Treharris, Pontypridd, Cardiff|
|- location||Cefn-coed-y-cymmer, Merthyr Tydfil, Wales|
|Length||64.0 km (40 mi)|
The River Taff (Welsh: Afon Taf) is a large 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.
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
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.
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 and flowing south-westwards around the Gurnos estate. 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. It is also known locally as Morlais Brook
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, as well as wiping out uncountable numbers of invertebrates. According to the Environment Agency Wales, it is estimated that the river will take between 6 and 12 years to recover, although it is making rapid progress. As of the summer of 2009 the trout population is once again breeding. The river is much revered by fly fisherman and the fishing rights are owned by Merthyr Tydfil Angling Association.
Underneath Cefn 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 Troedyrhiw, Merthyr Vale and Aberfan towards Quakers Yard. Here, the Taff Bargoed 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
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 as nickname
The term "Taffy", used as a nickname for people from the Taff Valley up to and including Cardiff and by extension from anywhere in Wales, is sometimes thought to originate from the name of the river. It may be seen as derogatory. The Oxford English Dictionary, however, states that the origin is "an ascribed Welsh pronunciation of Davy or David, in Welsh Dafydd."
- Pont-y-Cafnau, world's earliest surviving iron railway bridge
- "Cardiff Arms Park, A short History - The Creation of the Arms Park". Cardiff Council. Retrieved 2008-05-22.
- Morlais Brook Update - Merthyr Tydfil Angling Association
- River Taff Corridor Action Plan April 2007, page 7
- "Taffy, n.2". Oxford English Dictionary. Retrieved 2013-04-02.
- Glamorgan-Gwent Archaeological Trust Merthyr Tydfil Features