Water is a tricky thing. Take almonds for example. One almond takes about 4 liters of water to produce. With 1.6 billion pounds of almonds grown per year we're looking at almost 2.5 trillion liters of water. This is just one nut. Pistachios and walnuts use similar amounts of water, so do other things we eat like broccoli. I blame Coca-Cola and their ilk for the obesity epidemic, but water shortages are more caused by…
> One almond takes about 4 liters of water to produce How long does it take for that water to re-enter the ecosystem in a usable way? Water isn't just destroyed, yeah? Water planning is definitely worthwhile, but seems there are a few other variables in play.
It depends on where you got the water from. If you got it from a river or lake, probably "until the next time it rains". If you got it from an aquifer, then it depends on how long it takes water to filter down into the aquifer, assuming it can do so at all.
> Water isn't just destroyed, yeah?
In the case of aquifers it actually can be, effectively. Per https://en.wikipedia.org/wiki/Aquifer#Human_dependence_on_gr... second paragraph:
Fresh-water aquifers, especially those with limited recharge by
snow or rain, also known as meteoric water, can be over-exploited
and depending on the local hydrogeology, may draw in non-potable
water or saltwater intrusion from hydraulically connected aquifers
or surface water bodies. This can be a serious problem, especially
in coastal areas and other areas where aquifer pumping is excessive.
In some areas, the ground water can become contaminated by arsenic
and other mineral poisons.
https://en.wikipedia.org/wiki/Ogallala_Aquifer#Aquifer_water... is a worthwhile read with specific numbers for a specific aquifer that illustrates some of the possible problems.All of which is to say that in some places (and in particular in much of the Western US) water may closer to a non-renewable resource than a renewable one if it comes from an aquifer. At least on years-to-decades timescales.