Afon Llynfi (Wye)
Encyclopedia
The Afon Llynfi is a short river in the county of Powys
, south Wales
. A tributary of the River Wye
, it runs approximately south to north just to the west of the Black Mountains
and partly within the Brecon Beacons National Park. The river rises as a small stream to the west of the village of Bwlch
and flows north for 2 miles into Llangorse Lake
. It leaves the lake just to the southwest of the village of Llangors
and follows a course past the hamlets of Trefecca and Tredustan, then between the twin villages of Talgarth
and Bronllys
, forming the boundary of the national park in part. It then flows northeast past the village of Three Cocks otherwise known as Aberllynfi
before entering the River Wye just upstream of Glasbury
Bridge.
The Afon Llynfi is joined by a number of tributary streams including the Tawel and Gwlithen on its left bank and the Nant Cwy (emptying directly into the lake) and Nant yr Eiddil on its right bank. The two largest tributaries are those of the Dulas which enters on the left just above Bronllys Castle Bridge and the River Ennig which enters just downstream on the opposite bank, having flowed through Talgarth. The publicly accessible falls at Pwll y Wrach on this tributary are a local attraction.
During the deglaciation of Wales there was a period when ice from the Wye Valley Glacier blocked the exit of the river into the Wye. The waters of the Llynfi backed up at Llangors to the point where they overflowed the col
s at Pennorth and at Bwlch
(both at a height of 189m) and flowed south into the River Usk
which was by this time free of ice. This situation prevailed for several hundred years as evidenced by lake deposits beneath and around Llangorse Lake.
Powys
Powys is a local-government county and preserved county in Wales.-Geography:Powys covers the historic counties of Montgomeryshire and Radnorshire, most of Brecknockshire , and a small part of Denbighshire — an area of 5,179 km², making it the largest county in Wales by land area.It is...
, south Wales
Wales
Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...
. A tributary of the River Wye
River Wye
The River Wye is the fifth-longest river in the UK and for parts of its length forms part of the border between England and Wales. It is important for nature conservation and recreation.-Description:...
, it runs approximately south to north just to the west of the Black Mountains
Black Mountains, Wales
The Black Mountains are a group of hills spread across parts of Powys and Monmouthshire in southeast Wales, and extending across the national border into Herefordshire, England. They are the easternmost of the four ranges of hills that comprise the Brecon Beacons National Park, and are frequently...
and partly within the Brecon Beacons National Park. The river rises as a small stream to the west of the village of Bwlch
Bwlch
Bwlch is a small village on a col between two hills, where the present day A40 road now runs, between Brecon and Crickhowell in Powys, southern Wales...
and flows north for 2 miles into Llangorse Lake
Llangorse Lake
Llangorse Lake is the largest natural lake in south Wales, and is situated in the Brecon Beacons National Park, near to the town of Brecon and the village of Llangors....
. It leaves the lake just to the southwest of the village of Llangors
Llangors
Llangors is a small village in southern Powys, Mid Wales, and also falls inside the Brecon Beacons National Park....
and follows a course past the hamlets of Trefecca and Tredustan, then between the twin villages of Talgarth
Talgarth
Talgarth is a small market town and community in southern Powys , Mid Wales, with a population of 1,645. Notable buildings in the town include its 14th-century parish church and 13th century Pele Tower, located in the town centre, now home to the Tourist Information and Resource Centre...
and Bronllys
Bronllys
Bronllys is a village in Powys, Wales between the nearby towns Brecon and Talgarth. It has recently benefitted from a new bypass as part of the Talgarth Relief Road and Bronllys Bypass scheme....
, forming the boundary of the national park in part. It then flows northeast past the village of Three Cocks otherwise known as Aberllynfi
Aberllynfi
Aberllynfi is a village in Powys, Wales close to Glasbury. The name refers to the mouth of the Afon Llynfi which enters the River Wye just east of the village...
before entering the River Wye just upstream of Glasbury
Glasbury
Glasbury , also known as Glasbury-on-Wye, is a village in Powys, Wales which lies at an important crossing point on the River Wye, connecting the former counties of Brecknockshire and Radnorshire. The village is just outside the Brecon Beacons National Park, north of the Black Mountains. The...
Bridge.
The Afon Llynfi is joined by a number of tributary streams including the Tawel and Gwlithen on its left bank and the Nant Cwy (emptying directly into the lake) and Nant yr Eiddil on its right bank. The two largest tributaries are those of the Dulas which enters on the left just above Bronllys Castle Bridge and the River Ennig which enters just downstream on the opposite bank, having flowed through Talgarth. The publicly accessible falls at Pwll y Wrach on this tributary are a local attraction.
During the deglaciation of Wales there was a period when ice from the Wye Valley Glacier blocked the exit of the river into the Wye. The waters of the Llynfi backed up at Llangors to the point where they overflowed the col
Mountain pass
A mountain pass is a route through a mountain range or over a ridge. If following the lowest possible route, a pass is locally the highest point on that route...
s at Pennorth and at Bwlch
Bwlch
Bwlch is a small village on a col between two hills, where the present day A40 road now runs, between Brecon and Crickhowell in Powys, southern Wales...
(both at a height of 189m) and flowed south into the River Usk
River Usk
The River Usk rises on the northern slopes of the Black Mountain of mid-Wales, in the easternmost part of the Brecon Beacons National Park. Initially it flows north into Usk Reservoir, then east by Sennybridge to Brecon before turning southeast to flow by Talybont-on-Usk, Crickhowell and...
which was by this time free of ice. This situation prevailed for several hundred years as evidenced by lake deposits beneath and around Llangorse Lake.