Helensburgh No. 1 Reservoir
Argyll and Bute, United Kingdom
The Helensburgh No. 1 reservoir is of the non-impounding variety. It is no longer part of the local water supply system and is used by Helensburgh Angling Club. The earthen dam is 6 metres high and records show it was constructed before 1868.
Reservoir data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).