Garreg Ddu Reservoir

E237073

man-made lake reservoir

Garreg Ddu Reservoir is a scenic man-made lake in the Elan Valley of mid-Wales, known for its distinctive submerged dam and role in supplying water to the city of Birmingham.

Try in SPARQL Jump to: Surface forms Disambiguation Statements Elicitation Referenced by

All labels observed (5)

Label	Occurrences
Garreg Ddu Dam	3
Garreg Ddu Reservoir canonical	3
Garreg-ddu Reservoir	3
Craig Goch Reservoir	1
Garreg Ddu Reservoir (downstream via system)	1

How this entity was disambiguated

This entity first appeared as the object of triple T2115145 — 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: Garreg Ddu Reservoir
Context triple: [Rhayader, hasNearbyReservoir, Garreg Ddu Reservoir]

A. Ladybower Reservoir
Ladybower Reservoir is a large Y-shaped drinking-water reservoir in the Upper Derwent Valley of Derbyshire, England, known for its distinctive plughole spillways and surrounding Peak District scenery.
B. Howden Reservoir
Howden Reservoir is a large man-made lake in Derbyshire’s Peak District, known as part of the Upper Derwent Valley chain of reservoirs supplying water to nearby cities and popular for its scenic surroundings and outdoor recreation.
C. Abbeystead Reservoir
Abbeystead Reservoir is a man-made lake in Lancashire, England, known for its scenic setting within the Forest of Bowland and its role in regional water supply.
D. Derwent Reservoir
Derwent Reservoir is a large man-made lake in Derbyshire, England, best known for its scenic surroundings in the Peak District and its historical association with the World War II "Dambusters" training flights.
E. Foziling Reservoir
Foziling Reservoir is a major multipurpose water conservancy project in Anhui Province, China, known for flood control, irrigation, and water supply within the Huai River basin.
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: Garreg Ddu Reservoir
Target entity description: Garreg Ddu Reservoir is a scenic man-made lake in the Elan Valley of mid-Wales, known for its distinctive submerged dam and role in supplying water to the city of Birmingham.

A. Ladybower Reservoir
Ladybower Reservoir is a large Y-shaped drinking-water reservoir in the Upper Derwent Valley of Derbyshire, England, known for its distinctive plughole spillways and surrounding Peak District scenery.
B. Howden Reservoir
Howden Reservoir is a large man-made lake in Derbyshire’s Peak District, known as part of the Upper Derwent Valley chain of reservoirs supplying water to nearby cities and popular for its scenic surroundings and outdoor recreation.
C. Abbeystead Reservoir
Abbeystead Reservoir is a man-made lake in Lancashire, England, known for its scenic setting within the Forest of Bowland and its role in regional water supply.
D. Derwent Reservoir
Derwent Reservoir is a large man-made lake in Derbyshire, England, best known for its scenic surroundings in the Peak District and its historical association with the World War II "Dambusters" training flights.
E. Foziling Reservoir
Foziling Reservoir is a major multipurpose water conservancy project in Anhui Province, China, known for flood control, irrigation, and water supply within the Huai River basin.
F. None of above. chosen

Statements (38)

Predicate	Object
instanceOf	man-made lake ⓘ reservoir ⓘ
accessibleFrom	Elan Valley Visitor Centre ⓘ linked to: Elan Valley
basinCountry	United Kingdom ⓘ
constructionMaterialOfDam	masonry ⓘ
country	Wales ⓘ
hasFeature	stone road bridge over dam ⓘ surrounding hills ⓘ tree-lined shores ⓘ
hasInfrastructure	aqueduct to Birmingham ⓘ
hasNearbyActivity	birdwatching ⓘ cycling ⓘ
hasStructure	Garreg Ddu Dam ⓘ linked to: Garreg Ddu Reservoir
hasType	upland reservoir ⓘ
hasViewOf	Elan Valley ⓘ
impounds	River Elan ⓘ
knownFor	scenic landscape ⓘ submerged dam ⓘ
locatedIn	Elan Valley ⓘ Powys ⓘ mid-Wales ⓘ
locatedInProtectedArea	Elan Valley Estate SSSI ⓘ linked to: Elan Valley Estate
managesFlowTo	Caban Coch Reservoir ⓘ
near	Caban Coch Dam ⓘ Claerwen Reservoir ⓘ Pen-y-Garreg Reservoir ⓘ linked to: Pen-y-garreg Reservoir
operator	Dŵr Cymru Welsh Water ⓘ
partOf	Birmingham water supply system ⓘ linked to: Chew Valley water supply system Elan Valley Estate ⓘ Elan Valley Reservoirs ⓘ linked to: Elan Valley reservoirs
purpose	drinking water supply ⓘ water regulation ⓘ
river	River Elan ⓘ
usedFor	angling ⓘ recreation ⓘ walking ⓘ wildlife observation ⓘ
waterSupplyFor	Birmingham ⓘ

How these facts were elicited