matric suction in sand vs height of soil wrt water table

[owner-sowacs@aqua.ccwr.ac.za]

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> Reply to Ginny Carrera
> 
> A sand, particularly a pure sand of dune origons will have a very
> uniform grain size.   That means it also has a uniform pore size which
> in turn means that if a  column of saturated  sand is subjected to
> higher and higher suctions (raised further above the water table) , it
> will not change water content very much at all until a particular
> suction is reached, then nearly all the water drains at once.   I have a
> sand which drains at 49.5cm suction precisely leaving the sand water
> content virtually zero..    As the silt and clay content increase, the
> material will drain slowly over a wider range of suctions and will not
> drain completely.
> 
> The suction at which it wets will also be very precise - but it is
> unlikely to be the same suction as that at which it drains.
> cliff.hignett@soilwater.com.au
> 
> owner-sowacs@aqua.ccwr.ac.za wrote:
> 
> > NOTE:  To get off this list, send email to majordomo@aqua.ccwr.ac.za
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> >
> > Jiny Carrera asks
> >
> > In a sand (free of osmotic suction) what is the
> > relationship between matric suction and the height of
> > the soil with respect to the water table?
> >
> > Is this relationship the same for both, wetting and
> > drying process?
> >
> > __________________________________________________
> 
> --
> Cliff Hignett
> Soil Water Solutions
> 45a Ormond Ave
> Daw Park
> South Australia 5041
> pH 61 (08) 8276 7706
> WWW.SOILWATER.COM.AU
> 
> 
> 
> 
>