Afon Merddwr is a river in the south of the county of

Conwy Conwy (, ), previously known in English as Conway, is a walled market town, community and the administrative centre of Conwy County Borough in North Wales. The walled town and castle stand on the west bank of the River Conwy, facing Deganwy ...

, Wales. It is a tributary of the

River Conwy The River Conwy (; ) is a river in north Wales. From its source to its discharge in Conwy Bay it is long and drains an area of 678 square km. "Conwy" was formerly anglicised as "Conway." The name 'Conwy' derives from the old Welsh words ''c ...

and joins it near

Pentrefoelas Pentrefoelas is a village and Community (Wales), community in Conwy County Borough, Wales. The village lies on the A5 road (Great Britain), A5 road between Betws-y-Coed to the west and Cerrigydrudion to the east. Afon Merddwr, a tributary of the ...

. It is about 10 km long. "Merddwr" is Welsh for ''

backwater Backwater or Backwaters may refer to: Music * ''Backwaters'' (album), a 1982 album by American guitarist Tony Rice * Backwater (band), a jazz fusion band from Mobile, Alabama, or this band's 1976 debut album * "Backwater", a song by Brian Eno fr ...

'' or ''

stagnant water Water stagnation occurs when water stops flowing for a long period of time. Stagnant water can be a significant environmental hazard. Dangers Malaria and dengue are among the main dangers of still water, which can become a breeding ground ...

'', suggesting that it was named for its current or water quality. Y Merddwr - geograph

Course of the river

The source of the river is on the southern slopes of Mwdwl-eithin (532 m), the highest hill in Mynydd Hiraethog (the Denbigh Moors). Its name for the first part of its course is Afon Llaethog ("Milky River"). It flows south before turning west near the small village of Glasfryn. Several streams flow down from the hills into the river as it flows through

wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

and

marshes In ecology, a marsh is a wetland that is dominated by herbaceous plants rather than by woody plants.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p More in general ...

to its confluence near Rhydlydan with the Afon Nug, a small stream that flows from the hills above Pentrefoelas. The marshes are a

Site of Special Scientific Interest A Site of Special Scientific Interest (SSSI) in Great Britain, or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland, is a conservation designation denoting a protected area in the United Kingdom and Isle ...

known as

Corsydd Nug a Merddwr This is a list of the Sites of Special Scientific Interest (SSSIs) in the Conwy Area of Search (AoS). Sites References

{{Protected areas of Wales Lists of Sites of Special Scientific Interest by Area of Search, Conwy Sites of Sp ...

("Nug and Merddwr Marshes"). The river flows beside the

A5 road A5 Road may refer to: ;Africa * A5 highway (Nigeria), a road connecting Lagos and Ibadan * A5 road (Zimbabwe), a road connecting Harare and Bulawayo ;Americas * Quebec Autoroute 5, a road in Quebec, Canada * County Route A5 (California) or Bowm ...

, under a bridge for the B5113 near Pentrefoelas, and on for another 2 km to the River Conwy north of

Ysbyty Ifan Ysbyty Ifan (formerly anglicised as ''Yspytty Ifan'') is a small, historic village and community (Wales), community in the Conwy County Borough of Wales. The population in 2011 was 196 in 76 households (29 household spaces had no usual resident ...

References

{{Authority control Merddwr Merddwr