Afon Mawddach

Afon Mawddach
Afon Mawddach
	The Mawddach looking west to Barmouth Bay
Location
Country	Wales
Physical characteristics
Mouth
• location	Barmouth

Afon Mawddach (Welsh for 'River Mawddach') is a river in Gwynedd, Wales, which has its source in a wide area SH820300 north of Dduallt in Snowdonia. It is 28 miles (45 km) in length, and is much branched; many of the significant tributaries are of a similar size to the main river. The catchment area is bounded to the east by the Aran Fawddwy massif and to the west and north by the Harlech dome which forms a watershed just south of Llyn Trawsfynydd.

The Mawddach has been the site of significant industrialisation and land management. Gold mining and subsequently gold panning have had major impacts but forestry, the preparation of animal skins, the storage of old munitions and the use of hill-sides as artillery ranges have all added to the legacy of pollution. The river is also very flashy - prone to very rapid rise and fall in level depending on rainfall. Rainfall can also be very heavy and it falls on very base-poor soils leading to episodes of strongly depressed pH. Despite this, the river sustains an important salmon and trout fishery and the countryside through which it flows is some of the most spectacular and scenic in the UK.

The main tributaries starting in the west and working clockwise are:

Afon Cwm Mynach which drains Llyn Cwm Mynach on the Rhinogydd.
Afon Gamlan which joins at Ganllwyd after following a tumultuous valley through ancient oak woods before descending towards the main river down Rhaeadr Ddu (Black waterfalls). This valley has one of the more important moss and liverwort communities in the southern UK.
Afon Eden - its headwaters known as Afon Crawcwellt - a large tributary draining from below Llyn Trawsfynydd and closely following the A470 through the Coed-y-Brenin forest. This tributary has been severely affected by industrialisation in the past, including gold mining and its use as an ordnance range.
Afon Gain, a large tributary which has also been impacted by similar problems to the Eden and is very acidic and peaty.
Afon Wen which joins south of the Gain is similar but smaller.
Afon Wnion is a major tributary joining from the east and which drains a large area out towards Aran Fawddwy

Estuary

Below Dolgellau the river enters a wide and sandy estuary of great beauty. The head of the estuary is marked by the confluence of the Mawddach and Wnion. At its mouth is the town of Barmouth and its railway bridge.

Geology

The Mawddach estuary was formed from a glaciated valley which was flooded by the sea during the Holocene glacial retreat to form a fjord.^[1]

The valley occupied by the present Mawddach was later infilled by coarse-grained sub-glacial and pro-glacial deposits. In the Holocene (12,000 BP - present), gravel from the Irish Sea was introduced to the estuary.^[2]

Human history

The southern bank of the Mawddach estuary, along which used to run a section of the GWR branch line from Ruabon to Barmouth, has now been designated the Mawddach Trail, an 8-mile cycle path running from Dolgellau to Morfa Mawddach, at the south side of the Barmouth railway bridge. It is managed by the Eryri National Park Authority as a leisure route for walkers and cyclists, and is part of the Sustrans Cross-Wales Cycling Route.

The estuary of the Mawddach was a great centre of ship building in the 18th century and probably for some centuries before. There is no evidence remaining of this activity in the estuary today.

Panorama of the Mawddach towards Penmaenpool and Cadair Idris

References

^ Thomas, Peter; Howe, George Melvyn (1968). Welsh Landforms and Scenery. MacMillan.
^ The late devensian and holocene evolution of Barmouth Bay, Wales, Piers Larcombe, 1994

External links

52°51′16″N 3°45′14″W / 52.85452°N 3.75388°W / 52.85452; -3.75388

[WLaS-1] Thomas, Peter; Howe, George Melvyn (1968). Welsh Landforms and Scenery. MacMillan.

[2] The late devensian and holocene evolution of Barmouth Bay, Wales, Piers Larcombe, 1994

[1]

[2]

v t e Gwynedd
Principal settlements	Bala Bangor Barmouth Bethesda Blaenau Ffestiniog Caernarfon Criccieth Dolgellau Ffestiniog Harlech Nefyn Porthmadog Pwllheli Tywyn
Towns and villages	Aberangell Aberdaron Aberdesach Aberdyfi Abererch Abergeirw Abergwyngregyn Abergynolwyn Aberllefenni Abersoch Abertrinant Afon Wen Anelog Arthog Beddgelert Bethania Bethel Bethesda Betws Garmon Bodferin Boduan Bontddu Bontnewydd Botwnnog Bryncroes Bryn-crug Brynrefail Buan Bwlch-derwin Caeathro Capel Celyn Carmel Carnguwch Ceidio Chwilog Clwt-y-bont Clynnog Fawr Corris Uchaf Corris Croesor Cwm-y-glo Deiniolen Dinas Dinas Dinlle Dinas Mawddwy Dinorwig Dolbenmaen Dolmelinllyn Dwygyfylchi Edern Efailnewydd Eisingrug Fairbourne Friog Frongoch Ganllwyd Garndolbenmaen Garneddwen Gellilydan Glasinfryn Groeslon Llan Ffestiniog Llanaber Llanaelhaearn Llanarmon Llanbedr Llanbedrog Llanberis Llandanwg Llanddeiniolen Llandegwning Llandudwen Llandwrog Llandygai Llanegryn Llanelltyd Llanengan Llanfaelrhys Llanfaglan Llanfair Llanfihangel Bachellaeth Llanfihangel-y-Pennant Llanfihangel-y-Pennant, Dolbenmaen Llanfrothen Llangelynnin Llangian Llangwnnadl Llangybi Llaniestyn Llanigian Llanllechid Llanllyfni Llannor Llanrug Llanuwchllyn Llanwnda Llanymawddwy Llanystumdwy Llithfaen Llwyndyrys Llwyngwril Maentwrog Mallwyd Mellteyrn Minffordd Morfa Bychan Morfa Nefyn Mynydd Llandygai Mynydd Nefyn Mynytho Nantlle Valley Nantmor Nasareth Nebo Pant Glas Pen-y-meinl Penffridd Penisa'r Waun Penllech Penllyn Penmaenpool Pennal Penrhos Penrhyndeudraeth Pentre Gwynfryn Penygroes Pistyll Pontrug Porthdinllaen Portmeirion Prenteg Rachub Rhiwddolion Rhos-y-gwaliau Rhosgadfan Rhoshirwaun Rhoslefair Rhostryfan Rhyd Ddu Rhyd Rhyd-uchaf Rhydyclafdy Sarn Meyllteyrn Soar Tal-y-llyn Talsarnau Tal-y-bont (near Bangor) Tal-y-bont (near Barmouth) Talysarn Tanygrisiau Trawsfynydd Trefor Tregarth Tremadog Tudweiliog Tywyn Waunfawr Y Felinheli Y Ffor Y Fron Y Rhiw
Education	Bangor University Coleg Harlech Coleg Meirion-Dwyfor Coleg Menai Schools
Castles and forts	Caernarfon Castle Castell y Bere Criccieth Castle Dolbadarn Castle Harlech Castle Fort Belan
Rivers	Afon Aber River Adda Afon Artro Afon Cegin Afon Cwmnantcol Afon Daron Afon Dwyfor Afon Dwyryd Afon Dysynni Afon Fathew Afon Glaslyn Afon Llyfni Afon Mawddach Afon Ogwen Afon Rhythallt Afon Seiont Afon Tryweryn
Islands	Bardsey Island Ynys Gifftan Ynys Gwylan-fawr Saint Tudwal's Islands
Topics	Parliamentary constituencies Churches Places Schools SSSIs Country houses Listed buildings Grade I Grade II* Registered parks and gardens History Lord Lieutenants High Sheriffs Museums Public art
Geography Wales

Authority control databases
International	VIAF
National	United States Israel