By my calculations (and they could be wrong--English major here), it would hold 11,320 gallons.
Volume = πr2h = π(45.040848895006380022594105034422)2(40)
Approx 2.1 Imperial gallons = 2.5 US gallons.
13,464.94 US gallons.
4745 gallons Best estimate I have.
Approx 4892 Imperial gallons.
There are 907.9202769 feet2 of water, but you will have to convert that into gallons.
29,610.94 gallons (rounded)
10 .863 gallons
201.97 US gallons == Mer om kalkylatorn.
The capacity of the tank is 12.468 gallons (rounded) for each inch the tank is long.
84
You need to tell us how deep it is.
1,000,000 US gallons is about 134,000 cubic feet. A round tank of 56 feet diameter by 56 feet high will hold 1 million US gallons. Also a round pond of about 413 feet diameter by 1 foot deep.