What is the English name for the river known in Wales as Afon Dyfrdwy?
River Dee, Wales Dubr Duiu"; the name appears to derive from the Brythonic "dēvā": "River of the Goddess" or "Holy River". The total catchment area of the River Dee down to Chester Weir is . The estimated average annual rainfall over the catchment area is , yielding an average flow of 37 m/s. The larger reservoirs in the catchment area are: The River Dee has its source on the slopes of Dduallt above Llanuwchllyn in the mountains of Snowdonia in Meirionydd, Gwynedd, Wales. Between its source and Bala Lake the river is known by its Welsh name, "Afon Dyfrdwy". Legend tells that the
Afon Seiont with the addition of the waters of the Afon Arddu which drains the northern slopes of Snowdon. The name of the Roman fort of Segontium, near Caernarfon, is based on the Latinised form of the name 'Seiont'. Afon Seiont Afon Seiont (Welsh, meaning "River Seiont" in English) is a river in Gwynedd, Wales which runs into the Menai Strait. Its source is the outflow of Llyn Padarn near Llanberis, and it flows out in a generally northwest direction. Between the outflow and the village of Llanrug it is known as the Afon Rhythallt, changing its name just after the village.