Rain doesn’t come that often, so I can’t imagine how there could be enough to constantly keep the groundwater and aquifers flowing strong. I know there are some other sources like snowmelt too, but rain is the main one and I don’t see it being substantial enough to be able to bring that much water.
In: Earth Science
> How is there enough rainwater to keep aquifers recharged all the time?
There isn’t, necessarily.
For instance the [Ogallala Aquifer](https://en.wikipedia.org/wiki/Ogallala_Aquifer), which underlays much of the Great Plains.
> Since 1950, agricultural irrigation has reduced the saturated volume of the aquifer by an estimated 9%. Once depleted, the aquifer will take over 6,000 years to replenish naturally through rainfall.[6]
Also, think of the ground like a sponge – it’s full of fractures that slow the seepage of rainfall into an aquifer and some aquifers have fewer discharge points where groundwater becomes surface water. The land the rain falls on has a lot more surface area than you probably realize as well for recharge contribution and vegetation also slows the introduction of rainfall into the ground. These factors, among others, are what help keep the recharge/discharge cycle in balance. That being said, it’s common for aquifers to dry up during drought or new aquifers to establish during periods of excessive saturation.
The “charged” level of an acquifer is whatever level rainfall gets it to. It’s not even a question of balance: it’s a definition.
This made me think, so I did some digging.
A giant thunderhead cloud can have as much as 2 billion pounds if water in it.
That said, many aquifers are no longer in balance, as the demands of people and agriculture remove more than nature puts in. The short-term saving grace is that we are talking enormous amounts of water stored to start with.
I mentioned agriculture, growing a single pound of almonds takes 1900 gallons of water. 500 gallons of water will get you a pound of avocado. And for a measly 35 gallons of water you can have one cup of coffee.
Agriculture is super water intensive. So next time someone tells you aquifers are being depleted, it isn’t just the car wash and the lawn.
If you’re near any sort of river or lake system, water will also filter in from there. However, in a lot of places, there’s major problems that there isn’t enough rain to refill the aquifers. Large sections of California are sinking by several inches a year because the aquifers are being depleted so quickly
The aquifers were in balance with the amount that went in balanced by the amount that comes in at least until humans arrive; while each rain shower might not represent a great depth of water the area that the shower covers is huge so represents a lot of water. https://youtu.be/xbUfVLxYVcE
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