Afon Eden is a tributary river than runs into the

Afon Mawddach The Afon Mawddach ( en, River Mawddach, italic=yes) is a river in Gwynedd, Wales, which has its source in a wide area north of Dduallt in Snowdonia. It is 28 miles (45 km) in length, and is much branched; many of the significant tribut ...

Gwynedd Gwynedd (; ) is a county and preserved county (latter with differing boundaries; includes the Isle of Anglesey) in the north-west of Wales. It shares borders with Powys, Conwy County Borough, Denbighshire, Anglesey over the Menai Strait, and C ...

Wales Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...

. It is a protected river because it is one of the few breeding grounds for

freshwater pearl mussel The freshwater pearl mussel (''Margaritifera margaritifera'') is an endangered species of freshwater mussel, an aquatic bivalve mollusc in the family Margaritiferidae. Although the name "freshwater pearl mussel" is often used for this species ...

References

{{Authority control Rivers of Gwynedd Rivers of Snowdonia