Talk:Groundwater

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  • be parallel to the water table). --kris 23:52, 5 December 2005 (UTC)
[as an aside, I don't think this talk page is probably the best place to learn about groundwater.]


Just a note, when I checked the Environment Canada Website and the Coastal Ocean Institute Website, I got the impression that the vast majority of usable freshwater is groundwater (Coastal Ocean Institute Website says 97%). I don't doubt the statistic that 20% of the world's total freshwater is groundwater, but the statistic can be a bit misleading to someone who doesn't know the other 80% of this freshwater is in the icecaps and inaccessable to nearly everyone. —Preceding unsigned comment added by 129.21.112.186 (talk • contribs)

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[edit] Later discussion

'Groundwater' is the correct spelling in Australia in any case

Are you sure? Many engineers in US use the single term out of poor education in english. It's easier for them to remember. But it is still incorrect. —Preceding unsigned comment added by Dbt23 (talk • contribs) 14:25, 7 September 2006

[edit] Underwater streams

I have often heard people refer to 'underwater streams', as if the water flowed underground in some kind of narrow channel. Dowsers sometimes refer to this, I believe.

However, I suspect this never happens, apart from caves in limestone areas (and possibly lava tubes, but I suspect there's not much water in lava flows). And I suppose you could get pockets in fractured rock, although such pockets probably fill up with clay rather quickly. Rather, I suspect that groundwater is fairly uniformly distributed in the ground, and furthermore that any flow is extremely slow. Fast enough to re-charge a well, but certainly not like a stream.

If that's correct, then I would imagine an artesian spring would be the result of a relatively permeable rock layer being exposed in a very small area (or of a limestone cave, of course).

Can anyone confirm this? And if so, edit the article to correct this common misconception (if it is a misconception!). Mcswell (talk) 19:58, 8 June 2008 (UTC)

[edit] Subsidence and aquifer capacity

The section on subsidence seems entirely wrong to me - I was under the impression that subsidence occurs where the aquifer is of compressible soil, and that only some part of the subsidence is recoverable, and with it, the capacity. Can someone provide a reference for the theory expounded in the subsidence subsection? Argyriou (talk) 02:03, 21 November 2006 (UTC)

A small fraction of the subsidence is elastic, and therefore recoverable. The vast majority of the land subsidence in most cases is non-elastic, since the clays and silts in aquitards have re-arranged and cannot simply re-inflate back to their pre-development state. If you Google for "USGS subsidence California", you will find lots of USGS report and papers which state the theory and show consolidation data to back it up (I can remember seeing some figures which show there were feet of subsidence and a few inches of rebound in San Jose). There was subsidence in the central valley and San Jose area which the USGS did a bunch of reports on over the years. --kris 18:42, 21 November 2006 (UTC)
I understand consolidation and rebound (I'm a geotechnical engineer). However, it's the contention that subsidence comes from consolidation of the aquitard that I question. There are plenty of soil deposits in which water flows moderately well horizontally, but poorly vertically, including those in the Bay margins and the Central Valley. Those layers are subject to consolidation, and thus would lose capacity as aquifers as they settled. The article as written appears to believe that all aquifers are essentially granular soils or rock formations, and that subsidence is related to water draining out of the aquitards, not the aquifers. Argyriou (talk) 19:06, 21 November 2006 (UTC)

[edit] thanks

this is very resourceful for research for school and i think you should make more web sites like this. thank you... do not write back :) —The preceding unsigned comment was added by 216.99.112.151 (talk) 14:58, 16 April 2007 (UTC).

[edit] Safe Drinking Water Act

In my quick scan of this article, I did not see any reference to the Safe Drinking Water Act which regulates discharges that might affect groundwater. Some sort of reference should be included. —The preceding unsigned comment was added by 206.170.183.60 (talk) 21:51, 14 May 2007 (UTC).

see -- Safe Drinking Water Act
I don't know if they want groundwater to be expanded more to include the water act or not. Brian Pearson 14:51, 17 October 2007 (UTC)
It might be worth including something, but that would also add a strong U.S.-centric bias to the article. Better would be to discuss legal mechanisms for protecting groundwater worldwide, and include reference to the US act, and to similar laws in other countries. Argyriou (talk) 16:51, 17 October 2007 (UTC)
Sounds good. I'm not up to it, now. Maybe somebody else can do it. Brian Pearson 01:48, 18 October 2007 (UTC)

[edit] Cleaning groundwater pollution; transgenic poplars

Transgenic poplars can clean up a number of contaminants in the groundwater. [1] Brian Pearson 04:35, 16 October 2007 (UTC)


[edit] Problems deforestation

if i had good citations i'd put this directly in the article, but it is my understanding that forests, in particular, are the largest single natural phenomenon for both cleaning, and maintaining a natural aquifer. since forests prevent run-off from leaving the forest floor, both though preventing surface groundwater evaporation, and leaving organic debris that 'soaks' up rainfall until it becomes ground water, as well as increasing the amount of 'precipitation' that returns to the atmosphere after a rain fall, causing collateral rainfall downwind, usually withing a day or two of the first rainfall... it is my understanding that the rapid deforestation of Brazil's rain-forest has caused parts of the amazon river to drop by a lot. —Preceding unsigned comment added by 66.191.101.81 (talk) 23:43, 11 February 2008 (UTC)