ˈ The Afon Ogwen (; ; Welsh, meaning River Ogwen in English) is a river in north-west Wales draining from some of the greatest peaks in Snowdonia before discharging to the sea on the eastern side of Bangor, Gwynedd. Etymology Although the spoken form in the local North Wales dialect is Ogwan (with an A), and it has also recently been shown that Ogwan is an original form of the name; the form Ogwen is believed to have been mistakenly adopted as a kind of back-formation, because many words ending in -en become -an in the north Wales dialect. The name of the river is recorded as Oguanw (with the U doing duty for modern F) in a poem in the Hendregadredd Manuscript. The name is probably a compound word: og + Banw (after language mutation, turns into 'Fanw') 'piglet' = ogfanw. The precise meaning of og is less clear, but it may either be cognate with the Irish Tír na n-Óg (land of youth) or else derive from the Proto-Indo-European *oku ("soon, fast"). Sources The main source of the Ogwen is in Llyn Ogwen, which is situated alongside the A5 road as it starts to descend through Snowdonia. However, the true source of the river lies in the three streams draining into Llyn Ogwen. These are Nant Gwern y Gof, Afon Denau, and Afon Lloer which itself has its source in the upland lake, Ffynnon Lloer. Waterfalls The Ogwen emerging at the western end of Llyn Ogwen immediately descends cataracts and waterfalls, known as Ogwen Falls in English and Rhaeadr Ogwen in Welsh, before continuing in a north-north-westerly direction down the glaciated Nant Ffrancon valley. Re-Engineered In the 1950s and 1960s, this stretch of the river was re-engineered to try to help drain the adjoining farmland. However, the beneficial effects were not significant and the ecological damage was great. In the 1990s, the Environment Agency, working with partners including the Countryside Council for Wales and farming groups, re-engineered the river to recreate pools and riffles with the intention of allowing the river to re-gain its original form and diversity of wildlife. As the river continues northwards, it passes close to the great waste tips of slate produced by the Penrhyn slate quarry. A dam was built in the Afon Ogwen at Ogwen Bank, in the early 20th century, to raise the level of the river in order to provide