River Tweed River Tweed The River Tweed, or Tweed Water (, ), is a river long that flows east across the Border region in Scotland and northern England. Tweed (cloth) derives its name from its association with the River Tweed. The Tweed is one of the great salmon rivers of Britain and the only river in England where an Environment Agency rod licence is not required for angling. "Tweed" is a British name of uncertain meaning. It flows primarily through the scenic Borders region of Scotland, and eastwards from the settlements on opposing banks of Birgham and Carham forms the historic boundary
River Wye river from Redbrook to Chepstow forms the border between England and Wales. The River Wye forms two Sites of Special Scientific Interest, one covering the Upper Wye ("Gwy Uchaf") above Hay-on-Wye, and one covering the Lower Wye ("Gwy Isaf") downstream to Chepstow. The criteria for inclusion of the river as an SSSI include geology, topography, flora, mammals, invertebrates, fish and birdlife, as the river and its tributaries constitute a large linear ecosystem. The Lower Wye SSSI is itself divided into seven units of assessment set by Natural England, and administrative responsibilities are shared between the county authorities of Powys, Herefordshire,