Re: tensiometer problem ?

[Dani Or <dani@tal.agsci.usu.edu>]

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Philip,
This is perfectly O.K. - when the soil is saturated to the depth of the ceramic cup and in the presence of a positive pressure (water ponding on the surface) a tensiometer will behave exactly like a piezometer. Check any soil physics books for details. In fact, this also indcates that your system of measurement (SDEC) was performaning correctly.

Regards,
Dani Or
owner-sowacs@aqua.ccwr.ac.za wrote:
> 
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> 
> Date: Mon, 23 Aug 1999 18:41:32 +0200
> 
>   Dear subscribers to SoWaCs,
> 
> I'm working on Wetland hydrology in the Seine valley (France). To
> investigate unsaturated zone
> I used SDEC tensiometers and the SDEC portable electronic readout unit.
> I've done two years of measurements and it worked very good except during
> flood events (site was
> covered by a 30cm thick watershed sometimes during the study period).
> During those events, the depression measured by the tensiometer was positive !
> Does anybody encount the same problem ??
> 
> Thank you,
> 
>         Philippe.
>
-------------------------------------------------------------------------------
> Philippe WENG
> UMR Sisyphe
> Structure et fonctionnement des syst¸mes hydriques continentaux
> Laboratoire de Gˇologie Appliquˇe
> Tour 26, 5¸me ˇtage, Case 123
> 4, place Jussieu
> 75252 PARIS cedex 05
> tˇl: 01/44/27/51/22
> fax: 01/44/27/51/25
>
---------------------------------------------------- 
Dr. Dani Or
Associate Professor - Soil Physics
Depts. of Plants, Soils, and Biometeorology and Biological and Agricultural Engineering Utah State University
Logan, Utah 84322-4820
Phone: (435) 797-2637
Fax: (435) 797-2117

Email: dani@tal.agsci.usu.edu
http://tal.agsci.usu.edu/~tal/pages/or/index.html

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