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The definition of water table given here is, unfortunately, plain wrong. The water table is a pressure surface, where water below the ground surface is at atmospheric pressure. There is now abundant evidence that many soils are unsaturated below the water table (as given by the free-water surface in wells). For example, in peat soils, biogenic gas bubbles form below the water table due to anaerobic decay. Andy Baird, Professor of Physical Geography, Queen Mary, University of London (4th November 2005).
The definition of "water table" here is extremely similar to the definition of "aquifer" at
aquifer. Could anyone clarify the situation?
True that you don't need an aquifer to have a water table, but I was just trying to put the links which were in context at the beginning of the article.
Shouldn't this entry have the definition of a water table (the surface where the water is at atmostpheric pressure)? :Those other things (air+water vs water) are consequence or come from the definition. Some of this might be repeated from Aquifer#Saturated_vs._Unsaturated, so maybe it should just link to there? or move it over here? - kris 16:42, 11 Feb 2005 (UTC)
I have a graduate school education, and I cannot make heads or tails of this definition. -- Flange the Flee ( talk) 23:03, 1 May 2014 (UTC)
I added in a subject about the rising salt water tables in Australia. it would really help if someone expanded it since it is a good subject for this page but I know just some infromation about it. 66.229.47.105 04:24, 15 January 2006 (UTC)userBrenda
(This is a copyvio!) Source: [2]
im doing work on the water table for science i need to know "why we need to draw water several feet below the water table and not above it or on it." but i cant find the answer ive been searching for a few days can someone tel me that b-4 tomorrow PLZ I NEED THIS THIS THANGS DO TOMORROW —The preceding unsigned comment was added by 68.154.242.62 ( talk) 23:13, 8 March 2007 (UTC).
I cannot see where long-term fluctuation of water tables is addressed at all under that heading in the article. How the long-term fluctuations affect surface streamflow is what I'd really like to hear something about. Is channelized streamflow greater or lesser in a region as water tables rise in the geological long haul? Would a constantly flowing stream be changed to intermittent with rising water tables, or with falling water tables. — Preceding unsigned comment added by 69.246.166.209 ( talk) 02:30, 3 February 2015 (UTC)
I temporarily removed the following confusing statement from the intro paragraph:
Image:Vadose zone.gif from the USGS depicts these as the same thing. Can anyone explain a circumstance in which the phreatic-vadose boundary would be different from the water table? The articles linked to by the above sentence and the other text in the intro seem to treat them as if they were the same thing. -- Beland 18:59, 25 March 2007 (UTC)
As an an unsaturated soil engineer I take the Phreatic Surface to be the level at which the ground water is at atmospheric pressure (i.e. no more positive hydrostatic pressure) and the Water Table to be the interface between fully-saturated ground and partially saturated ground. In gravel layers this means they are the same thing, but in clays with large suctions they can be metres apart. I'll try and find an internet page to back this up, instead of the books I have. If no-one has any objections I will then change the page. Philip Wallbridge 14:41, 1 November 2007 (UTC)
Why does the water table vary in height in the diagram? Is it because the river is draining water at a high rate, but it flows slowly through the soil? The article seems to imply it is due to variations in the gravitational field of the planet due to topography, which, if the image is taken to be at scale, is incorrect. -- Beland 19:02, 25 March 2007 (UTC)
I have never seen a river surface that was curved like the one in the diagram. Bjartmarr ( talk) 18:41, 12 May 2008 (UTC)
"Water table" has a completly different meaning in architcture, see: water table (architecture) Ferritecore ( talk) 14:46, 27 July 2008 (UTC)
I think the relationship between the water table and rivers can be clarified. The article and illustrations currently give the impression that the water of a river is (all, mostly) originating from the water of the phreatic zone along its course. Large rivers it seems get most of their water from tributaries, and those tributaries may start as runoff, not ground water.
So what proportion of a typical river's water is being added from the phreatic zone along its course? Must a river surface always be not higher than the water table -- or can water from elsewhere flow through a channel that is entirely above the water table (depending on flow volume and geology)? Are there situations where the river channel is well above the water table, and leeching water downwards into it?
This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||
|
The definition of water table given here is, unfortunately, plain wrong. The water table is a pressure surface, where water below the ground surface is at atmospheric pressure. There is now abundant evidence that many soils are unsaturated below the water table (as given by the free-water surface in wells). For example, in peat soils, biogenic gas bubbles form below the water table due to anaerobic decay. Andy Baird, Professor of Physical Geography, Queen Mary, University of London (4th November 2005).
The definition of "water table" here is extremely similar to the definition of "aquifer" at
aquifer. Could anyone clarify the situation?
True that you don't need an aquifer to have a water table, but I was just trying to put the links which were in context at the beginning of the article.
Shouldn't this entry have the definition of a water table (the surface where the water is at atmostpheric pressure)? :Those other things (air+water vs water) are consequence or come from the definition. Some of this might be repeated from Aquifer#Saturated_vs._Unsaturated, so maybe it should just link to there? or move it over here? - kris 16:42, 11 Feb 2005 (UTC)
I have a graduate school education, and I cannot make heads or tails of this definition. -- Flange the Flee ( talk) 23:03, 1 May 2014 (UTC)
I added in a subject about the rising salt water tables in Australia. it would really help if someone expanded it since it is a good subject for this page but I know just some infromation about it. 66.229.47.105 04:24, 15 January 2006 (UTC)userBrenda
(This is a copyvio!) Source: [2]
im doing work on the water table for science i need to know "why we need to draw water several feet below the water table and not above it or on it." but i cant find the answer ive been searching for a few days can someone tel me that b-4 tomorrow PLZ I NEED THIS THIS THANGS DO TOMORROW —The preceding unsigned comment was added by 68.154.242.62 ( talk) 23:13, 8 March 2007 (UTC).
I cannot see where long-term fluctuation of water tables is addressed at all under that heading in the article. How the long-term fluctuations affect surface streamflow is what I'd really like to hear something about. Is channelized streamflow greater or lesser in a region as water tables rise in the geological long haul? Would a constantly flowing stream be changed to intermittent with rising water tables, or with falling water tables. — Preceding unsigned comment added by 69.246.166.209 ( talk) 02:30, 3 February 2015 (UTC)
I temporarily removed the following confusing statement from the intro paragraph:
Image:Vadose zone.gif from the USGS depicts these as the same thing. Can anyone explain a circumstance in which the phreatic-vadose boundary would be different from the water table? The articles linked to by the above sentence and the other text in the intro seem to treat them as if they were the same thing. -- Beland 18:59, 25 March 2007 (UTC)
As an an unsaturated soil engineer I take the Phreatic Surface to be the level at which the ground water is at atmospheric pressure (i.e. no more positive hydrostatic pressure) and the Water Table to be the interface between fully-saturated ground and partially saturated ground. In gravel layers this means they are the same thing, but in clays with large suctions they can be metres apart. I'll try and find an internet page to back this up, instead of the books I have. If no-one has any objections I will then change the page. Philip Wallbridge 14:41, 1 November 2007 (UTC)
Why does the water table vary in height in the diagram? Is it because the river is draining water at a high rate, but it flows slowly through the soil? The article seems to imply it is due to variations in the gravitational field of the planet due to topography, which, if the image is taken to be at scale, is incorrect. -- Beland 19:02, 25 March 2007 (UTC)
I have never seen a river surface that was curved like the one in the diagram. Bjartmarr ( talk) 18:41, 12 May 2008 (UTC)
"Water table" has a completly different meaning in architcture, see: water table (architecture) Ferritecore ( talk) 14:46, 27 July 2008 (UTC)
I think the relationship between the water table and rivers can be clarified. The article and illustrations currently give the impression that the water of a river is (all, mostly) originating from the water of the phreatic zone along its course. Large rivers it seems get most of their water from tributaries, and those tributaries may start as runoff, not ground water.
So what proportion of a typical river's water is being added from the phreatic zone along its course? Must a river surface always be not higher than the water table -- or can water from elsewhere flow through a channel that is entirely above the water table (depending on flow volume and geology)? Are there situations where the river channel is well above the water table, and leeching water downwards into it?