|≈||approximately equal to|
|digits||indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …)|
The acre-foot is a unit of volume commonly used in the United States in reference to large-scale water resources, such as reservoirs, aqueducts, canals, sewer flow capacity, irrigation water, and river flows.
With the adoption of the imperial system the kilderkin was redefined to be 18 imperial gallons, which is exactly 81.82962 litres or approximately 2.890 cubic feet.