Hetch Hetchy Reservoir
E584017
Hetch Hetchy Reservoir is a man-made lake in Yosemite National Park that stores water and generates hydroelectric power for the San Francisco Bay Area.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Hetch Hetchy Reservoir canonical | 6 |
How this entity was disambiguated
This entity first appeared as the object of triple T6103823 — 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: Hetch Hetchy Reservoir Context triple: [Hetch Hetchy Valley, knownFor, Hetch Hetchy Reservoir]
-
A.
Pepacton Reservoir
Pepacton Reservoir is a large man-made lake in the Catskill Mountains of New York that serves as a major component of New York City's drinking water supply system.
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B.
Hetch Hetchy Regional Water System
The Hetch Hetchy Regional Water System is a major water supply and delivery network that provides high-quality drinking water from Sierra Nevada sources to San Francisco and numerous Bay Area communities.
-
C.
Hetch Hetchy Valley
Hetch Hetchy Valley is a glacially carved valley in Yosemite National Park, California, best known for its scenic granite cliffs and for being largely submerged by the Hetch Hetchy Reservoir that supplies water to the San Francisco Bay Area.
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D.
Calaveras Reservoir
Calaveras Reservoir is a major water storage reservoir in California’s Diablo Range that supplies drinking water to the San Francisco Bay Area.
-
E.
Pardee Reservoir
Pardee Reservoir is a man-made lake in the Sierra Nevada foothills of California that serves as a major water storage and supply source for the East Bay region.
- 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: Hetch Hetchy Reservoir Target entity description: Hetch Hetchy Reservoir is a man-made lake in Yosemite National Park that stores water and generates hydroelectric power for the San Francisco Bay Area.
-
A.
Pepacton Reservoir
Pepacton Reservoir is a large man-made lake in the Catskill Mountains of New York that serves as a major component of New York City's drinking water supply system.
-
B.
Hetch Hetchy Regional Water System
The Hetch Hetchy Regional Water System is a major water supply and delivery network that provides high-quality drinking water from Sierra Nevada sources to San Francisco and numerous Bay Area communities.
-
C.
Hetch Hetchy Valley
Hetch Hetchy Valley is a glacially carved valley in Yosemite National Park, California, best known for its scenic granite cliffs and for being largely submerged by the Hetch Hetchy Reservoir that supplies water to the San Francisco Bay Area.
-
D.
Calaveras Reservoir
Calaveras Reservoir is a major water storage reservoir in California’s Diablo Range that supplies drinking water to the San Francisco Bay Area.
-
E.
Pardee Reservoir
Pardee Reservoir is a man-made lake in the Sierra Nevada foothills of California that serves as a major water storage and supply source for the East Bay region.
- F. None of above. chosen
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf | reservoir ⓘ |
| accessVia | Hetch Hetchy Road NERFINISHED ⓘ |
| basinCountry |
United States of America
ⓘ
surface form:
United States
|
| completionDate | 1923 ⓘ |
| constructionStartDate | 1914 ⓘ |
| country |
United States of America
ⓘ
surface form:
United States
|
| createdByDam | O'Shaughnessy Dam NERFINISHED ⓘ |
| elevation |
approximately 1,200 meters above sea level
ⓘ
approximately 3,800 feet above sea level ⓘ |
| environmentalImpact | inundated much of Hetch Hetchy Valley ⓘ |
| hasHydroelectricSystem | Hetch Hetchy Power System NERFINISHED ⓘ |
| hasNearbyTrail | Wapama Falls trail NERFINISHED ⓘ |
| hasNearbyWaterfall |
Tueeulala Falls
NERFINISHED
ⓘ
Wapama Falls NERFINISHED ⓘ |
| inflow | Tuolumne River NERFINISHED ⓘ |
| legalBasis | Raker Act NERFINISHED ⓘ |
| locatedIn |
Hetch Hetchy Valley
NERFINISHED
ⓘ
Sierra Nevada NERFINISHED ⓘ Tuolumne County, California NERFINISHED ⓘ Yosemite National Park ⓘ |
| locatedInProtectedArea | Yosemite National Park NERFINISHED ⓘ |
| locatedWithin | U.S. National Park System NERFINISHED ⓘ |
| managedBy | San Francisco Public Utilities Commission NERFINISHED ⓘ |
| maxLength |
about 13 kilometers
ⓘ
about 8 miles ⓘ |
| namedAfter | Hetch Hetchy Valley NERFINISHED ⓘ |
| nearestCity | Groveland, California NERFINISHED ⓘ |
| outflow | Tuolumne River NERFINISHED ⓘ |
| ownedBy | City and County of San Francisco NERFINISHED ⓘ |
| partOf |
Hetch Hetchy Project
NERFINISHED
ⓘ
San Francisco regional water system NERFINISHED ⓘ |
| providesPowerTo |
San Francisco Bay Area
NERFINISHED
ⓘ
San Francisco municipal facilities ⓘ |
| receivesWaterFrom | Sierra Nevada snowmelt ⓘ |
| region | Northern California ⓘ |
| subjectOf |
environmental controversy
ⓘ
proposals to restore Hetch Hetchy Valley ⓘ |
| surfaceArea |
about 1,940 acres
ⓘ
about 7.9 square kilometers ⓘ |
| treatsWaterBy | disinfection only (no filtration under normal conditions) ⓘ |
| usedFor |
flood control
ⓘ
hydroelectric power generation ⓘ municipal water supply ⓘ recreation (limited) ⓘ |
| volume |
about 430,000 acre-feet
ⓘ
about 530 million cubic meters ⓘ |
| waterQuality | high ⓘ |
| waterSupplyFor |
San Francisco
NERFINISHED
ⓘ
San Francisco Bay Area NERFINISHED ⓘ |
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: Hetch Hetchy Reservoir Description of subject: Hetch Hetchy Reservoir is a man-made lake in Yosemite National Park that stores water and generates hydroelectric power for the San Francisco Bay Area.
Referenced by (6)
Full triples — surface form annotated when it differs from this entity's canonical label.