Editing Snowdonia (section)

=== Rivers and lakes ===
Rivers draining the area directly into [[Cardigan Bay]] are typically short and steep. From north to south they include:
* the {{lang|cy|[[Afon Glaslyn|Glaslyn]]}} and {{lang|cy|[[Afon Dwyryd|Dwyryd]]}}, which share a common estuary,
* the {{lang|cy|[[Afon Mawddach|Mawddach]]|italic=no}} and its tributaries the [[River Wnion|Wnion]] and the {{lang|cy|[[Afon Eden|Eden]]|italic=no}},
* the smaller {{lang|cy|[[Afon Dysynni|Dysynni]]|italic=no}}
* and on the park's southern margin the {{lang|cy|[[River Dyfi|Dyfi]]|italic=no}}.

A series of rivers drain to the north coast. Largest of these is the [[River Conwy|Conwy]] on the park's eastern margin, which along with the {{lang|cy|[[Afon Ogwen|Ogwen]]|italic=no}} drains into [[Conwy Bay]]. Further west the {{lang|cy|[[Afon Seiont|Seiont]]|italic=no}} and {{lang|cy|[[Afon Gwyrfai|Gwyrfai]]|italic=no}} empty into the western end of the [[Menai Strait]]. Part of the east of the national park is within the upper [[River Dee, Wales|Dee (Dyfrydwy)]] catchment and includes [[Bala Lake]], the largest natural water body in Wales.

A fuller list of the rivers and tributaries within the area is found at [[List of rivers of Wales]].[[File:Snowdonia by drone.webm|thumb|Aerial video of parts of Northern Snowdonia (2014)]]There are few natural bodies of water of any size in Wales; Snowdonia is home to most. Besides Bala Lake, a few lakes occupy [[U-shaped valley|glacial troughs]], including {{lang|cy|[[Llyn Padarn]]|italic=no}} and {{lang|cy|[[Llyn Peris]]|italic=no}} at {{lang|cy|[[Llanberis]]|italic=no}} and  {{lang|cy|[[Tal-y-llyn Lake]]|italic=no}} south of {{lang|cy|Cadair Idris|size=no}}. {{lang|cy|[[Llyn Dinas]], [[Llyn Gwynant]]|italic=no}}, and {{lang|cy|[[Llyn Cwellyn]]|italic=no}} to the south and west of Snowdon feature in this category, as do {{lang|cy|[[Llyn Cowlyd]]|italic=no}} and {{lang|cy|Llyn Ogwen|italic=no}} on the margins of the {{lang|cy|Carneddau|italic=no}}. There are numerous small lakes occupying [[glacial cirque]]s, owing to the intensity of past [[glaciation|glacial action]] in Snowdonia. Known generically as [[tarn (lake)|tarn]]s, examples are {{lang|cy|[[Llyn Llydaw]], [[Glaslyn]]|italic=no}} and {{lang|cy|Llyn Du'r Arddu|italic=no}} on Snowdon, {{lang|cy|[[Llyn Idwal]]|italic=no}} within the {{lang|cy|Glyderau|italic=no}} and {{lang|cy|Llyn Cau|italic=no}} on {{lang|cy|Cadair Idris|italic=no}}.

There are two large wholly man-made bodies of water in the area, {{lang|cy|[[Llyn Celyn]]|italic=no}} and {{lang|cy|[[Llyn Trawsfynydd]]|italic=no}}, whilst a number of the natural lakes have had their levels artificially raised. {{lang|cy|[[Marchlyn Mawr]]|italic=no}} reservoir and {{lang|cy|italic=no|Ffestiniog}} Power Station's {{lang|cy|Llyn Stwlan|italic=no}} are two cases where natural tarns have been dammed as part of [[Pumped-storage hydroelectricity|pumped storage hydro-electric schemes]].<ref>{{cite web |title=Ffestiniog Power Station |url=https://www.fhc.co.uk/en/power-stations/ffestiniog-power-station/ |website=First Hydro Company |access-date=30 May 2020}}</ref>

A fuller list of the lakes within the area is found at [[List of lakes of Wales]]. In 2023, the park [[List of standardised Welsh lake names in Snowdonia|standardised its Welsh language lake names]], to be also used in English.<ref>{{Cite news |date=2023-11-15 |title=Snowdonia: Eryri National Park to use Welsh lake names only |language=en-GB |publisher=BBC News |url=https://www.bbc.com/news/uk-wales-67431789 |access-date=2023-11-25}}</ref>