March 12, 2023 – It’s March madness once again as we try to explain water conditions in California to real people in the midst of additional basketball madness.
We all enjoy and suffer with basketball. This commonality can make it a useful unit of volume among the many units of volume used for water.
A cubic foot has the volume of about 4 basketballs. So a flow of 1,000 cubic feet per second (cfs) has a volume equivalent of having 4,000 basketballs coming at you every second.
An acre-foot (af) is a volume one foot deep over an acre of area. It has a volume of 43,560 cubic feet or 325,850 gallons, or 174,240 basketballs.
One cfs flowing for one day (24 hours) discharges almost 2 acre-feet (1.98) of volume (348,480 basketballs/day).
A million gallons per day (mgd) has the same volume as 1.87 million basketballs per day. (There are 7.48 gallons per cubic foot)
A cubic meter (m3) is about 35.3 cubic feet, which equals about 141 basketballs of volume.
Here is a California water units translator (rounded some, highlighting the most useful conversions):
For California’s water infrastructure, the Sacramento Valley flood bypass system has a conveyance capacity of almost 750,000 cubic feet per second (600,000 cfs in the lower Yolo Bypass and 130,000 cfs in the Sacramento River main stem). This is equivalent to the volume of 3 million basketballs per second (260,000 mega-basketballs per day – mbd).
California’s largest reservoir has a storage capacity of 4.55 million acre-feet, or almost 800 billion basketballs.
In terms of water use, most of California’s roughly 8 million acres of irrigated agriculture uses 3-4 acre-ft per acre annually (520,000-700,000 basketballs per acre/year) each year totaling about 26 million acre-ft per year, or 4.5 trillion basketballs of water per year.
California’s urban water users, almost 40 million people, use roughly 140 gallons per capita per day (74 basketballs/person-day or 27,100 basketballs/person-year), totaling about 7 million acre-ft per year, or 1.2 trillion basketballs of water per year of urban water use.
Maybe this basketball lens for California water use is helpful for “#SciComm” junkies and others at pains to communicate scienterrific things to real people. As a civil engineering undergraduate student, it seemed that a third of all my calculations were unit conversions. We might have learned more with a single standard international unit such as basketballs (since metric hasn’t caught on much here). (Still, if I made a mistake in the table, let me know.)
Welcome to March Madness!