The River Rhiw ( cy, Afon Rhiw meaning 'slope river' or 'stream river') is a short

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

in the north of

Powys Powys (; ) is a Local government in Wales#Principal areas, county and Preserved counties of Wales, preserved county in Wales. It is named after the Kingdom of Powys which was a Welsh succession of states, successor state, petty kingdom and princi ...

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 ...

. Two headwater tributaries both named Afon Rhiw flow east to join at Dwyrhiew and then continue in a generally easterly direction to join the

River Severn , name_etymology = , image = SevernFromCastleCB.JPG , image_size = 288 , image_caption = The river seen from Shrewsbury Castle , map = RiverSevernMap.jpg , map_size = 288 , map_c ...

east of

Berriew Berriew ( cy, Aberriw) is a village and community in Montgomeryshire, Powys, Wales. It is on the Montgomeryshire Canal and the Afon Rhiw, near the confluence (Welsh: ''aber'') with the River Severn (Welsh: Afon Hafren) at , 79 miles (128 km ...

( cy, Aberriw ‘mouth of the Rhiw’). The northern Rhiw emerges from Llyn y Bugail (Welsh: ‘lake of the shepherd’) on Mynydd Waun Fawr whilst the southern Rhiw rises near Mynydd Dwyriw. The combined river flows past the hamlets of New Mills ( cy, Felin Newydd),

Manafon Manafon is a small rural community located in the hills of Montgomeryshire, the Northern part of the Welsh county of Powys. The Parish focuses on the valley of the River Rhiew that runs west to east into the River Severn". The community of Manafo ...

and Pant-y-ffridd, accompanied by the B4390 road all the way to Berriew. Other tributaries include the Nant Wtre-wen, Crygnant, Nant y Llyn Mawr and Dolgar Brook. It is bridged and forded at numerous points, one of which is an aqueduct carrying the

Montgomery Canal The Montgomery Canal ( cy, Camlas Trefaldwyn), known colloquially as "The Monty", is a partially restored canal in eastern Powys and northwest Shropshire. The canal runs from the Llangollen Canal at Frankton Junction to Newtown via Llanymy ...

over it at Berriew. At the eastern end of the river is Glansevern Hall and gardens.

Etymology

The Welsh word ''rhiw'' means 'slope' in which case it would be 'slope river' but it is suggested that it may be derived from a British word ''riu'' meaning stream. The modern anglicised name Berriew is derived from Aberriw ('aber' + mutated 'rhiw' signifying 'mouth of the Rhiw')

References

River Rhiw {{Wales-river-stub