River Dwyryd

River Dwyryd

The River Dwyryd (in Welsh "Afon Dwyryd") is a river in Gwynedd, North Wales, which flows principally westwards draining to the sea into Tremadog Bay south of Porthmadog.

The Dwyryd rises in the hills to the north of Ffestiniog. At its most northern extent, water draining from Moelwyn Mawr drains into the Tanygrisiau Reservoir, the outflow of which forms the source of the Afon Goedol. This is joined by the Afon Bowydd at grid reference: gbmaprim|SH695438|SH695438. Below Rhyd y Sarn, the river is joined by the Afon Cynfal which flows from the east down a deep wooded gorge which includes the spectacular Rhaeadr Cynfal (Cynfal waterfall) south of Ffestiniog. The main river from here on flows through a wide valley formed by glaciation but with a broad flat base formed from re-worked glacial moraines and riverine gravel deposits. The valley, the Vale of Ffestiniog, is worked for agriculture but is subject to routine winter flooding.

Afon Tafarn-Helyg has its confluence about one mile further downstream. This tributary rises south of Gellilydan just north of the Trawsfynydd reservoir but does not receive any water from the reservoir.

There are a number of small lakes and reservoirs in the woodlands north of Plas Tan y Bwlch which also drain south into the river. These lakes include Llyn y Garnedd, Llyn Hafod y Llyn and the beautiful Llyn Mair.

Trawsfynydd reservoir, a large impoundment close to the A470, is the only inland water in the UK that has been used as a source of cooling water for a nuclear power station. The outflow from Trawsfynydd reservoir forms the headwater of the Afon Prysor which flows down another steeply wooded valley before joining the main river at Maentwrog. Large parts of the flow from the reservoir is channelled through the hydro-electric power station at Maentwrog and the flow from the station re-joins the Prysor before the confluence.

As the river moves into a long tidal estuary, it flows under the railway line and under a toll road and rail bridge known as Pont Briwet. Due south of Portmeirion the river is joined by the Afon y Glyn which drains the south west catchment from Llyn Tecwyn Uchaf and Llyn Tecwyn Isaf. The confluence is adjacent to Glastraeth ("green beach") - a large extent of salt marsh.

The estuary of the Dwyryd is long and sandy and includes the confluence of the Afon Glaslyn close to the low water mark. The estuary is hauntingly beautiful, though some consider it spoiled by the crossing of National Grid pylons.

The whole of the river drains off igneous and ancient rocks of the Cambrian and Ordovician which are all base-poor. Much of the catchment has also been used for commercial forestry during the last hundred years. As a consequence, many of the tributaries are highly acidic as a result of atmospheric acidification. This has constrained the quality of the fishery and the bio-diversity in many tributaries. Some of these problems have been exacerbated by past industrial actions including metal mining, slate mining, animal skin processing and the use by the army of a gunnery range with large amounts of implaced metal cartridge shells.


Wikimedia Foundation. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • River Glaslyn — The River Glaslyn ( Afon Glaslyn in Welsh) is a river in Gwynedd, north west Wales. Whilst not of great significance in terms of its length (about 16 miles), it is one of Gwynedd s primary rivers, and has greatly influenced the landscape in which …   Wikipedia

  • River Mawddach — Afon Mawddach River Mawddach looking west to Barmouth Bay Mouth Barmouth Basin countries Wales The …   Wikipedia

  • Penrhyndeudraeth — ( peninsula with two beaches in Welsh) is a village in Gwynedd, Wales. It is located between the Traeth Mawr ( big beach ), the now largely reclaimed estuary of the River Glaslyn, and the Traeth Bach ( little beach ), the estuary of the River… …   Wikipedia

  • Maentwrog — River Dwyryd in Maentwrog …   Wikipedia

  • Portal:Wales — Wikipedia portals: Culture Geography Health History Mathematics Natural sciences People Philosophy Religion Society Technology …   Wikipedia

  • Trefriw — infobox UK place country = Wales welsh name= constituency welsh assembly= map type= official name= Trefriw population= 1,338 (2001 census) unitary wales= Conwy lieutenancy wales= Clwyd constituency westminster= Meirionnydd Nant Conwy post town=… …   Wikipedia

  • Slate industry in Wales — The slate industry in Wales began during the Roman period when slate was used to roof the fort at Segontium, now Caernarfon. The slate industry grew slowly until the early 18th century, then expanded rapidly until the late 19th century, at which… …   Wikipedia

  • Blaenau Ffestiniog — infobox UK place country = Wales welsh name= constituency welsh assembly= latitude= 52.99 longitude= 3.93 official name= Blaenau Ffestiniog population = 4830 unitary wales= Gwynedd lieutenancy wales= Gwynedd constituency westminster= Meirionnydd… …   Wikipedia

  • Traeth Mawr — The Traeth Mawr (Welsh for big sands ) is a polder near Porthmadog in Gwynedd in Wales. It was formerly the tidal estuary of the river Glaslyn, and many travellers sank in its quicksands trying to cross it. Much of it is between high mountains.… …   Wikipedia

  • Ceunant Llennyrch National Nature Reserve — Coordinates: 52°56′20″N 3°58′01″W / 52.939°N 3.967°W / 52.939; 3.967 Ceunant Llennyrch Nationa …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”