Llyn Trawsfynydd
E271628
Llyn Trawsfynydd is a large man-made reservoir in Gwynedd, Wales, originally constructed to supply cooling water for the now-decommissioned Trawsfynydd nuclear power station and now used for recreation and fishing.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Llyn Trawsfynydd canonical | 6 |
How this entity was disambiguated
This entity first appeared as the object of triple T2294246 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Llyn Trawsfynydd Context triple: [Trawsfynydd, hasBodyOfWater, Llyn Trawsfynydd]
-
A.
Llyn Tegid
Llyn Tegid, also known as Bala Lake, is the largest natural lake in Wales, renowned for its scenic beauty and unique aquatic wildlife.
-
B.
Llyn Llydaw
Llyn Llydaw is a glacial lake on the eastern flanks of Snowdon in Snowdonia National Park, Wales, renowned for its scenic mountain setting and association with local legends.
-
C.
Llyn Gwynant
Llyn Gwynant is a scenic lake in the Snowdonia region of North Wales, popular for its surrounding mountain views and outdoor activities such as hiking, kayaking, and camping.
-
D.
Llyn Dinas
Llyn Dinas is a scenic natural lake in the Snowdonia region of North Wales, popular for walking, photography, and its surrounding mountainous landscapes.
-
E.
Llyn Arenig Fawr
Llyn Arenig Fawr is a remote upland lake in Snowdonia, Wales, known for its scenic setting beneath the summit of Arenig Fawr and its use as a reservoir.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Llyn Trawsfynydd Target entity description: Llyn Trawsfynydd is a large man-made reservoir in Gwynedd, Wales, originally constructed to supply cooling water for the now-decommissioned Trawsfynydd nuclear power station and now used for recreation and fishing.
-
A.
Llyn Tegid
Llyn Tegid, also known as Bala Lake, is the largest natural lake in Wales, renowned for its scenic beauty and unique aquatic wildlife.
-
B.
Llyn Llydaw
Llyn Llydaw is a glacial lake on the eastern flanks of Snowdon in Snowdonia National Park, Wales, renowned for its scenic mountain setting and association with local legends.
-
C.
Llyn Gwynant
Llyn Gwynant is a scenic lake in the Snowdonia region of North Wales, popular for its surrounding mountain views and outdoor activities such as hiking, kayaking, and camping.
-
D.
Llyn Dinas
Llyn Dinas is a scenic natural lake in the Snowdonia region of North Wales, popular for walking, photography, and its surrounding mountainous landscapes.
-
E.
Llyn Arenig Fawr
Llyn Arenig Fawr is a remote upland lake in Snowdonia, Wales, known for its scenic setting beneath the summit of Arenig Fawr and its use as a reservoir.
- F. None of above. chosen
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
man-made lake
ⓘ
reservoir ⓘ |
| artificial | true ⓘ |
| basinCountry | United Kingdom ⓘ |
| completedIn | 1920s ⓘ |
| constructedFor | Trawsfynydd nuclear power station ⓘ |
| constructionStart | 1920s ⓘ |
| country | Wales ⓘ |
| createdBy | construction of dams ⓘ |
| currentUse |
angling
ⓘ
leisure ⓘ nature conservation ⓘ |
| hasArea |
approximately 1200 acres
ⓘ
approximately 4.8 square kilometres ⓘ |
| hasElevation | approximately 220 metres above sea level ⓘ |
| hasFacility |
boat launch points
ⓘ
car parks ⓘ fishing jetties ⓘ |
| hasFeature |
islands
ⓘ
surrounding conifer plantations ⓘ surrounding moorland ⓘ |
| hasFishSpecies |
brown trout
ⓘ
eels ⓘ perch ⓘ pike ⓘ rainbow trout ⓘ |
| hasRecreationalPath | circular lakeside path ⓘ |
| hasShoreLength | approximately 13 km ⓘ |
| inflow |
Afon Crawcwellt
ⓘ
Afon Prysor ⓘ |
| locatedIn |
Gwynedd
ⓘ
Eryri National Park ⓘ
surface form:
Snowdonia National Park
|
| locatedNear |
Blaenau Ffestiniog
ⓘ
Trawsfynydd ⓘ |
| managedBy | Natural Resources Wales ⓘ |
| nearStructure | Trawsfynydd nuclear power station ⓘ |
| nearTransportRoute | A470 road NERFINISHED ⓘ |
| originalUse |
industrial cooling
ⓘ
supporting nuclear power generation ⓘ |
| outflow | Afon Prysor ⓘ |
| partOf | Afon Dwyryd catchment ⓘ |
| purpose | cooling water supply ⓘ |
| region | north-west Wales ⓘ |
| usedFor |
boating
ⓘ
fishing ⓘ recreation ⓘ walking ⓘ wildlife observation ⓘ |
| waterBodyType | reservoir ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Llyn Trawsfynydd Description of subject: Llyn Trawsfynydd is a large man-made reservoir in Gwynedd, Wales, originally constructed to supply cooling water for the now-decommissioned Trawsfynydd nuclear power station and now used for recreation and fishing.
Referenced by (6)
Full triples — surface form annotated when it differs from this entity's canonical label.