Makes sense, since we usually measure rainfall in inches, it's pretty easy to look up weather records for an area to see what the minimum annual rainfall is expected to be.
It is specifically for reservoirs and by extension municipal water supply systems because it's relatively easy to determine the surface area and height of a reservoir
The comparable unit (in terms of estimating irrigation needs vs rainfall vs reservoir draw, which are the terms we reason with in this part of the US) would be the hectare-meter, which is 10,000 cubic meters.
For context, https://www.rubyhome.com/blog/swimming-pool-stats/ estimates that there are ~500k residential pools in Arizona. Note that those will likely be smaller than a half olympic-size swimming pool.
> The acre-foot is a non-SI unit of volume equal to about 1,233 m3 commonly used in the United States in reference to large-scale water resources, such as reservoirs, aqueducts, canals, sewer flow capacity, irrigation water,[1] and river flows.
It's a surprisingly convenient unit of measurement. Rainfall and irrigation typically are 0-1m per year, so if you have a 10acre farm you need 10acre-m of water to grow... Though, can't mix units, that would be silly :).
We measure our land in acres and water is the limiting resource for using it. Water requirements for crops are expressed in feet/year (or inches/day). Combine the two and you get acre-feet.
m^3 would be a less useful unit in terms of calculating water needs out here, the metric equivalent would be hectare-meters (10,000 m^3).
Yes, It's from farming. To state the obvious, it's the volume of water you'd have if a foot of rain fell on an acre of field.
So, it's the unit that gets used when discussing irrigation. Or water usage that competes with irrigation. :P
Makes sense, since we usually measure rainfall in inches, it's pretty easy to look up weather records for an area to see what the minimum annual rainfall is expected to be.
It is specifically for reservoirs and by extension municipal water supply systems because it's relatively easy to determine the surface area and height of a reservoir
We'll use anything but metric lol. It's about 1,233 cubic meters of water.
The comparable unit (in terms of estimating irrigation needs vs rainfall vs reservoir draw, which are the terms we reason with in this part of the US) would be the hectare-meter, which is 10,000 cubic meters.
Which is incidentally only 1% off from half an olympic-size swimming pool.
In other words, the fab requires about 20,000 swimming pools of water every year... or equivalently, 1 swimming pool every 27 minutes.
For context, https://www.rubyhome.com/blog/swimming-pool-stats/ estimates that there are ~500k residential pools in Arizona. Note that those will likely be smaller than a half olympic-size swimming pool.
https://en.m.wikipedia.org/wiki/Acre-foot
> The acre-foot is a non-SI unit of volume equal to about 1,233 m3 commonly used in the United States in reference to large-scale water resources, such as reservoirs, aqueducts, canals, sewer flow capacity, irrigation water,[1] and river flows.
Seems to be.
It's a surprisingly convenient unit of measurement. Rainfall and irrigation typically are 0-1m per year, so if you have a 10acre farm you need 10acre-m of water to grow... Though, can't mix units, that would be silly :).
Specifically in the desert west, yes.
We measure our land in acres and water is the limiting resource for using it. Water requirements for crops are expressed in feet/year (or inches/day). Combine the two and you get acre-feet.
m^3 would be a less useful unit in terms of calculating water needs out here, the metric equivalent would be hectare-meters (10,000 m^3).
Yeah, not uncommon at all in most scenarios where water volume is large enough.