Hayfield Water Supply
Harrymoor Tanks - elevated side view
Looks like 3 separate tanks at different levels? The chamber with the rusty coloured lid on the far left of the photo is shown on the next photo.
This following is assumed to refer to these tanks:
From the Public Health Report of 1940.
HAYFIELD: Sanction was given by the Ministry of Health for a loan of £3000 for the purpose of constructing a storage reservoir of 20,000 gallons. The work was completed during the year.

Photo taken 2022