r/askscience • u/juul_daddy • Mar 15 '23

Earth Sciences Will the heavy rain and snowfall in California replenish ground water, reservoirs, and lakes (Meade)?

I know the reservoirs will fill quickly, but recalling the pictures of lake mead’s water lines makes me curious if one heavy season is enough to restore the lakes and ground water.

How MUCH water will it take to return to normal levels, if not?

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u/awhildsketchappeared Mar 16 '23

The rain/snow ends the drought for the soil and the reservoirs, but groundwater takes much longer to recharge, and we have to actually stop making net withdrawals from ground aquifers for that to happen. I forget if we’ve at least returned to neutral on that. Definitely not before 2014 legislation kicked in.

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u/fireintolight Mar 16 '23

we most definitely are overdrawing on all major reservoirs still. Common phenomenon around the world. Consider for a second that Mexico City used to be Tenochtitlan which the Spanish had a hard time conquering because it was a city in the middle of a giant lake, now it's a dustbowl. Even if we stopped drawing from ground water it replenishes at a rate measured in thousands of years and is abysmally small amounts per year, there is no sustainable ground water usage. When you withdraw water from the soil the pore spaces left behind by the water are now crushed by the weight of the soil on top of it, leaving much much less space for water to occupy than before and makes the rate it flows into the soil even slower.