The River Tawe (; ) is a long river in South Wales. Its headwaters flow initially east from its source below Llyn y Fan Fawr south of Moel Feity in the Black Mountains, the westernmost range of the Brecon Beacons National Park, before the river turns south and then southwest to its estuary at Swansea. Its main tributaries are the right bank Upper and Lower Clydach Rivers and the Afon Twrch. The total area of the catchment is some . The Tawe passes through a number of towns and villages including Ystradgynlais, Ystalyfera, Pontardawe, and Clydach and meets the sea at Swansea Bay below Swansea. The Tawe Valley ( in Welsh) is more commonly known as the Swansea Valley. Ownership of the riverbed was granted to the Duke of Beaufort in the 17th century by Charles II resulting in exclusive mineral and fishing rights, which is extended as far as requiring permission and payment for bridges which are built over it. This was last exercised in 2008 when Swansea Council was required to pay £281,431 to the estate, as revealed by a Freedom of Information request. History The lower part of the valley was intensely industrialised in the 18th and 19th centuries and was especially impacted by metal refining and working and to a much lesser extent by porcelain manufacture. Large areas of the lower valley remain contaminated by industrial spoil containing copper, lead, nickel and zinc. The only significant extant relic of those times is a major nickel refinery at Clydach which is part of the Canadian company Vale Inco. The quality of the river has now greatly improved. Large salmon swim up the river to spawn, whilst trout are in abundance. In 1992, a barrage was built at the mouth of the river. National Cycle Route 43 follows this river for much of its course. Bridges and crossings Bridges over the River Tawe within the City and County of Swansea, from north to south: A4067 (Ffordd Cwm Tawe) road bridge B4291 road bridge at Glais A4067 road bridge (second crossing) former rail access to the Vale Inco works at Clydach disused railway bridge (former GWR route from Felin Fran to Clydach) A4067 road bridge (third crossing) Park Road bridge at Ynystawe M4 motorway bridge railway bridge (Swansea District Line) Swansea Vale road bridge A48 Morriston road bridge - links Morriston town centre to the Swansea Enterprise Park Beaufort