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 water for the use of the nearby Penrhyn Quarry and then past a caravan site, Ogwen Bank, where the remains of a long abandoned watermill and mill pond still exist. Passing Braichmelyn village on its eastern bank, it is joined by the substantial tributary, the Afon Caseg, which drains a large area of the Carneddau mountains. The course turns slightly more westwards as the river passes through Bethesda and becomes progressively more wooded and more deeply cut providing some white water conditions enjoyed by canoeists.