Environment & Energy

OKIsItJustMe

(19,938 posts) Thu Feb 9, 2017, 01:27 PM Feb 2017

Deep groundwater aquifers respond rapidly to climate variability

http://news.psu.edu/story/449807/2017/02/08/deep-groundwater-aquifers-respond-rapidly-climate-variability

[font face=Serif][font size=5]Deep groundwater aquifers respond rapidly to climate variability[/font]

By Matthew Carroll
February 8, 2017

[font size=3]UNIVERSITY PARK, Pa. — Changes in climate can rapidly impact even the deepest freshwater aquifers according to Penn State and Columbia University hydrologists.

The researchers found that responses to climate variations can be detected in deep groundwater aquifers faster than expected — in many cases within a year.

Because rain water may take years to reach deep aquifers through natural infiltration, the findings suggest another factor is involved, such as pumping of aquifers done by agricultural industries.

"We saw a rapid response in deep groundwater levels to both major climate cycles and local precipitation," said Tess Russo, R.L. Slingerland Early Career Professor of Geosciences at Penn State. "These aquifers are so deep, we expect it takes years for precipitation to make its way down, so if it's not natural recharge causing the response of groundwater to changes in precipitation, then it may be coming from pumping changes."

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http://dx.doi.org/10.1038/ngeo2883

3 replies

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Deep groundwater aquifers respond rapidly to climate variability (Original Post) OKIsItJustMe Feb 2017 OP

Might be a dumb question, but... OnlinePoker Feb 2017 #1

Doesn't seem like a dumb question to me OKIsItJustMe Feb 2017 #2

Great question! Canoe52 Feb 2017 #3

OnlinePoker

(5,722 posts)

1. Might be a dumb question, but...

Reply to OKIsItJustMe (Original post)

Thu Feb 9, 2017, 02:46 PM

Feb 2017

In areas where the aquifers are being pumped and the ground level subsides as a result, does that mean this capacity is lost forever? Even with infiltration, I would think there would be no place for the water to go. Areas of the California central valley have dropped tens of feet over the last 100 years due to this groundwater pumping.

OKIsItJustMe

(19,938 posts)

2. Doesn't seem like a dumb question to me

Reply to OnlinePoker (Reply #1)

Thu Feb 9, 2017, 02:49 PM

Feb 2017

However, I'm afraid the answer is yes.

https://water.usgs.gov/ogw/pubs/fs00165/

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The compaction of unconsolidated aquifer systems that can accompany excessive ground-water pumping is by far the single largest cause of subsidence. The overdraft of such aquifer systems has resulted in permanent subsidence and related ground failures. In aquifer systems that include semiconsolidated silt and clay layers (aquitards) of sufficient aggregate thickness, long-term ground-water-level declines can result in a vast one-time release of “water of compaction” from compacting aquitards, which manifests itself as land subsidence (fig. 2). Accompanying this release of water is a largely nonrecoverable reduction in the pore volume of the compacted aquitards, and thus a reduction in the total storage capacity of the aquifer system. This “water of compaction” cannot be reinstated by allowing water levels to recover to their predevelopment status. The extraction of this resource for economic gain constitutes “ground-water mining” in the truest sense of the term.

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Canoe52

(2,948 posts)

3. Great question!

Reply to OKIsItJustMe (Reply #2)

Fri Feb 10, 2017, 04:22 AM

Feb 2017

Something I've wondered myself, especially when viewing those pictures from California where the ground has dropped 20 - 30 feet over the years.

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