Hartley Reservoir itself was constructed between 1859-1862.
The reservoir area is about one and a third acres, with a depth of about 5 metres.
It has a capacity of approximately 7 million gallons (about 30.4 million litres) of water.
The excavated soil was deposited on the adjacement field, which has now become the mound in the park.
An early view of the uncovered reservoir, looking North West.
Whilst it looked pretty, there was no real knowledge of what lay beneath!
In a cleaning out operation conducted in January 1976, all manner of rubbish was found, including a crashed car.
Finally, work to drain the reservoir started in February 1981 and the capping was completed in March 1982.
A concrete roof, supported by 165 concrete pillars, was installed and grassed over for the use of outdoor leisure pursuits.
A fuller history of the provision of water to Plymouth in general and Hartley Reservoir, Park and area in particular
written by Vina Shaddick of "The Friends of Hartley Park", has been placed on the web:
link to History