Llyn y Fan Fawr

Llyn y Fan Fawr
Llyn y Fan Fawr is located in Powys
Llyn y Fan Fawr
Llyn y Fan Fawr
LocationPowys, Wales
Coordinates51°52′52″N 3°42′0″W / 51.88111°N 3.70000°W / 51.88111; -3.70000
Typenatural
Primary outflowsNant y Llyn, tributary of River Tawe
Basin countriesUnited Kingdom
Surface elevation605 m (1815 feet)

Llyn y Fan Fawr (Welsh for 'great lake (near) the peak')[1] is a natural lake in the county of Powys, Wales. It lies at the foot of Fan Brycheiniog,[2] the highest peak of the Black Mountain (Y Mynydd Du) range within the Brecon Beacons National Park. Created as a result of glacial action,[3] it is one of the largest glacial lakes in southern Wales.[4]

The lake from a small beach

Shoreweed and quillwort are found here whilst greater water-moss occurs on boulders at the water's edge. Freshwater limpets, caddisflies and leeches are also recorded. However, as regards fish, a C17th manuscript asserts that it "hathe no fishe attaile in't nither will any fish being put into it live, but as soon as they have tasted of this water turne up their silver bellies and suddenly dey."[5][6]

The surface of Llyn y Fan Fawr lies at about 1815 feet or 605m above sea level.[7][8] Its primary outflow is to the River Tawe.[9] Much of the land around the lake is peaty and thus wet underfoot. The main route of the Beacons Way runs along the ridge above the lake whilst its low-level alternative wraps around the lake's eastern margin.

  1. ^ Owen, Hywel Wyn; Morgan, Richard (2007). Dictionary of the Place-names of Wales (First ed.). Llandysul: Gomer Press. p. 300. ISBN 9781843239017.
  2. ^ Andrew Davies; David Whittaker (9 September 2010). Walking on the Brecon Beacons. Cicerone Press Limited. pp. 191–. ISBN 978-1-84965-346-6.
  3. ^ Geological Survey of Great Britain (1932). Memoirs. England and Wales: Explanation of Sheet. H.M. Stationery Office.
  4. ^ Derek Ratcliffe (26 January 2012). A Nature Conservation Review: Volume 1: The Selection of Biological Sites of National Importance to Nature Conservation in Britain. Cambridge University Press. pp. 236–. ISBN 978-0-521-20329-6.
  5. ^ Mullard, Jonathan (2014). The New Naturalist Library: Brecon Beacons. London: HarperCollins. pp. 226–227. ISBN 9780007367696.
  6. ^ Mullard, Jonathan (2014). The New Naturalist Library: Brecon Beacons. London: HarperCollins. pp. 226–227. ISBN 9780007367696.
  7. ^ Hans Luther; Julian Rzóska (1971). Project Aqua: A Source Book of Inland Waters Proposed for Conservation. International Biological Programme. ISBN 978-0-632-08730-3.
  8. ^ Ordnance Survey Explorer map OL12 'Brecon Beacons National Park: western area'
  9. ^ Bye-gones: Relating to Wales and the Border Counties. Printed at the Caxton works. 1894. pp. 504–.