Afon Senni
River in Powys, Wales / From Wikipedia, the free encyclopedia
The Afon Senni is a river in Powys, Wales which rises in the Fforest Fawr section of the Brecon Beacons National Park and flows northwards for 11 kilometres (7 mi) to a confluence with the River Usk at Sennybridge.
The river rises as Blaen Senni to the north of the peak of Fan Nedd and east of Fan Gyhirych (51.8621°N 3.5931°W / 51.8621; -3.5931 (Afon Senni (source))), occupying a deep glacial trough until it reaches the hamlet of Heol Senni. Before reaching Sennybridge (51.9455°N 3.5723°W / 51.9455; -3.5723 (Afon Senni (mouth))), it flows past the village of Defynnog, where it is joined on its left bank by its sole significant tributary, the Nant Treweryn (or Treweren).[1]
The river's name probably derives from a personal name 'Senni'.[2]
The river is designated as a special area of conservation in respect of its population of three species of lamprey, twaite shad, European bullhead, Atlantic salmon and otter.[3]