So far Dartefacts has visited the Harter Reservoir Boreholes, which have been capped and are therefore easy to find. Steve Grigg of Dartmoor Explorations has visited Swincombe. There are several other borehole sites on Dartmoor that look like they were prospective reservoirs. For example: 'Sampford Spiney Reservoir', 'Huccaby Reservoir', 'Cowsic Reservoir' and 'Taw Marsh Reservoir'
For further information visit this link: British Geological Survey Boreholes: Geology of Britain viewer.
https://mapapps2.bgs.ac.uk/geoindex/home.html?layer=BGSBoreholes
The map below is set to a maximum zoom of 1:50k. To zoom into the map further (1:25k) you need to be a subscriber. You can become a subscriber by visiting this page.
Or login here if you are already a subscriber.