Talk:Aquifer

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Depth of Aquifers

I was hoping to find some estimates or commonish values for how deep some of these huge aquifers are ... or how deep the aquifer by my place in Nowhereville, USA might be. 500 feet? 5000 feet? 5 miles? I can't any answer to this with a google search, either... cheater 04:38, 28 March 2006 (UTC)

The section on "Depth" should be rewritten and retitled. It contains zero information on the depth of aquifers. Useless. The USGS has a webpage which mentions depths of 10's and 100's of feet, and also mentions deeper water.98.21.215.86 (talk) 21:12, 9 April 2017 (UTC)

Capillary saturation issue

The capillary fringe can be un-saturated on a water content basis. This is an important distinction for modelling processes which depend on gas exchange/diffusion rates, such as in support of biological remediation. In a compacted fill this is not an important distinction, but in a natural setting with medium to fine textured soils, it can be. The exception would be in highly ordered materials and in coarse material where the capillary fringe would be on the order of a millimeter.

Water rises into the capillary due to surface tension but it normally cannot achieve 40% occupancy in the void space in the medium available to it. Due to variation in pore size, saturation (on a water content basis) is not typically achieved throughout the observed capillary fringe. Stated another way, when one observes the fringe moistened by capillary action above the level of free water, one is not observing saturated conditions throughout the material on a water content basis. Saturation is only occuring in the smallest pore spaces within the moistened fringe. Significant air content in the void portion is present and increases with distance above the free water depth.

Supporting references:

• Capillary Fringe: that zone of soil immediately above the water table (see Capillary Fringe) that acts like a sponge sucking water up from the underlying water table and retaining this water somewhat tenaciously. Soil pores act like capillary tubes. The smaller the soil pore, the greater is the rise of water within the soil pore. The pores within a soil matrix are typically composed of numerous pore sizes. At the base of the capillary fringe most if not all of the soil pores are completely filled with water. At the top of the capillary fringe, only the smallest soil pores are filled with water. Therefore, the water content of the capillary fringe decreases with increasing distance above the water table. The size of the diameter of the soil pore defines the capillary rise of the water column. It is possible that soils can be completely saturated with water, yet the water table is some number of feet below this point of complete saturation. The water table is defined by that point in the soil column where water is free to move; therefore, it is not tenaciously bound within the soil pores. The water table is physically determined by the level to which ground water flows into a porous pipe which has a diameter large enough so that capillary forces from this pipe cannot complicate the determination of the top of the water table.

• In those soils where the vertical thickness of the capillary fringe at least equals the depth to the water table, then the capillary fringe can behave as a wick, wicking the waters originating from the water table to soil surface where it can be evaporated to the atmosphere.

from http://www.earthdrx.org/definitions.html

• Capillary fringe: A zone in the soil just above the plane of zero gauge pressure that remains saturated or almost saturated with water. The extent can be inferred from the retentivity profile and depends upon the size-distribution of pores.

from http://www.soils.org/sssagloss/search.html

• capillary fringe—The zone above the water table and below the boundary of saturation where the soil is saturated but at pressures less than atmospheric (i.e., under tension). A new equivalent term gaining acceptance is tension saturated zone.

from http://amsglossary.allenpress.com/glossary/browse?s=c&p=6

Paleorthid 04:02, 12 September 2005 (UTC)

Too technical

This article needs to be made more accessible. I pulled it up when I wondered, "what is an aquifer?" Having read the article, I'm still not sure. Let's take the first paragraph of the main body:

This diagram indicates typical flow directions in a cross-sectional view of a simple confined/unconfined aquifer system (two aquifers with one aquitard between them, surrounded by aquiclude) which is in contact with a stream (typical in humid regions). The water table and unsaturated zone are also illustrated.

Yikes! Aquitard? Aquiclude? Flow directions? Unsaturated zone? Some (but not all) of these terms are defined later on, but you need to at least give the five-word subclause definition the first time you refer to a technical term.

This article made my head spin, and I'm a technician in training and profession. --TreyHarris 19:57, 28 December 2005 (UTC)

• 15-Oct-2007: Done (2 years later). I have added prior definitions of aquitard/aquiclude (other terms are linked), and I overlayed "(aquitard)" on the diagram, narrowed to allow more non-technical text to be added, while splitting sentences into simpler phrasing. Those changes follow the comments detailed above. I am removing the {technical}-tag at top, which did not simplify this article during the past 2 years. -Wikid77 08:54, 15 October 2007 (UTC)

The section on isotopic vs anisotropic is in particular need of improvement. 207.6.168.8 (talk) 21:52, 25 December 2010 (UTC)

Water Mining

Just wanted to point to the new article Water Mining that allows for a detailed discussion of over-pulling above recharge rates. 75.6.148.210 06:02, 29 September 2006 (UTC)

over pulling??? what kind of terminology is that? --kris 16:41, 29 September 2006 (UTC)

The image of a confined aquifer is wrong

There confining layer has no way for water to get below it, and the arrows under the stream imply that water is moving back up through the confining layer towards the steam. The point of calling a confining layer confining is that water does not move through it easily. The arrows also imply that water is moving upwards to enter the stream from the surface aquifer. This is also physically impossible. Water moves down a gradient of pressure. As long as there is water in the stream there is a pressure gradient pushing down on the ground water directly below it. This figure is embarrasing and should be replaced with a physically correct one. Someone with a good figure should put it in. —Preceding unsigned comment added by Primacag (talk • contribs) 00:38, 28 October 2008 (UTC)

The legend of the figure explains the "confining layer" as a layer of low hydraulic conductivity, not zero conductivity. So the problem is not that serious. Yet, the "confining layer" may be renamed "semi-confining layer". Horizontal transport of water through a semi-confining layer is limited, but the vertical transport can be appreciable. Also, the underlying aquifer may be called "semi-confined aquifer" rather than "confined aquifer". R.J.Oosterbaan (talk) 15:22, 23 May 2009 (UTC)

Largest Aquifer

It would appear the largest aquifer by volume is the Nubian Sandstone Aquifer System, rather than the Great Artesian Basin. Granted they are different types, i.e. the Great Artesian Basin is largest "re-chargeable" aquifer, while the Nubian aquifer is largest overall, but seen as non-renewable fossil water. Perhaps an explanation and distinction should be made in the article. — Preceding unsigned comment added by 198.84.171.123 (talk) 15:43, 29 January 2013 (UTC)

Misconceptions reconveived

I did not agree with the section header "misconceptions". We could blow up Wikipedia with misconceptions. As the contents were largely about rocks, i have renamed the section "rock formations" and made the necessary (minor) adjustments to the change of title.
What remains to be done is to distinguish aquifers in sedimentary (alluvial) formations from those in rock formations systematically. All the items in the section "classification" refer to extensive aquifers in alluvium with disregard of other formations. Hence, the section needs to be reworked to encompass a wider assortment of aquifers. R.J.Oosterbaan (talk) 15:22, 23 May 2009 (UTC)

Pronunciation

Is it "a-quiffer" because i think a lot of people say ackwi-fi-er? --87.113.55.177 (talk) 19:39, 11 October 2010 (UTC)

Yes it is the first example: \ˈa-kwə-fər, ˈä-\ however I this is a talk page about the article so i'm not sure this is appropriate discussion...207.6.168.8 (talk) 21:57, 25 December 2010 (UTC)

Add Etymology Section

The word has a pretty direct, yet interesting, etymology (Latin aqua = water, fer = bearer). This should be referenced in a new section or a short sentence in the lead. — Preceding unsigned comment added by Hayesgm (talk • contribs) 02:48, 25 February 2012 (UTC)

Add proper definitions

The terms aquitard, aquiclude, aquifuge are used without any proper definition, implying even that aquiclude and aquifuge are synonyms. — Preceding unsigned comment added by 128.178.7.131 (talk) 16:03, 28 November 2012 (UTC)

Perennial Firn Aquifers

I am not an expert on aquifers, but a news article referred to an aquifer under the Greenland Ice Sheet as a "perennial firn aquifer" and I was wondering if we should add a section to the Aquifer page that talks about this. Should I add it or can someone else (who knows more about this)? (The article is http://zeenews.india.com/news/eco-news/greenland-ice-harbours-massive-reservoir-of-melt-water_898753.html.) Bill.albing (talk) 23:09, 29 December 2013 (UTC)

paleovalley

I think this article should mention, and define, paleovalleys. About 20 other wikipedia articles use this term, and it isn't clear whether it is simply referring to unconfined aquifers, or near-surface valleys covered by uncemented sand (or other regolith), or whether deeper structures (or locations that formerly channelled water but no longer do) can also qualify. Cesiumfrog (talk) 04:10, 20 November 2014 (UTC)

Basal aquifer

Is this subsection really needed? It appears to apply to a specific aquifer system in the McMurray Formation of Alberta. Perhaps it should be moved to Examples. Georgialh (talk) 05:06, 17 January 2015 (UTC)

I moved it. Georgialh (talk) 23:43, 25 January 2015 (UTC)

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To what extent should groundwater pollution be mentioned?

I am a bit confused whether groundwater pollution should be mentioned a bit more in this section: "Challenges for uses of aquifers". There is a sub-article for groundwater pollution but I wonder if it should be mentioned with 2-3 sentences (maybe use excerpt from the other article?) or if it deviates too far from the topic of aquifers towards groundwater. Also, aquifers and groundwater are very closely related, and they actually overlap quite a bit. For example, at groundwater there is also a section on issues. We should streamline the two sections so that they don't overlap. EMsmile (talk) 08:33, 23 April 2021 (UTC)

Reduced overlap with groundwater

I have worked on reducing the overlap with groundwater by moving content about uses of groundwater and replacing that with an excerpt. I am still pondering how to deal with the "issues" section. I think overall, this article should be focused on the hydrogeological side of things, whereas the article on groundwater could focus on how humans use groundwater and how they impact on it. - This is work in progress, more work is needed. EMsmile (talk) 00:44, 14 May 2021 (UTC)

I've done more work on this now and moved the entire "issues" section to groundwater as it was very similar to the content there. This avoids overlap and is more efficient with regards to further work on the issues/challenges section. EMsmile (talk) 09:34, 18 May 2022 (UTC)