Solute transport and sub-surface irrigation

A discussion forum for users of the new HYDRUS 2D/3D. HYDRUS is a software package for simulating water, heat and solute movement in two- and three-dimensional variably saturated media. Happy Posting!
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nessrine
Posts: 15
Joined: Sun Jun 28, 2015 9:38 pm
Location: Tunisia

Solute transport and sub-surface irrigation

Post by nessrine » Wed Sep 25, 2019 3:12 pm

Hi
I'm working with Hydrus 2D/3D , I want to simulate water flow and solute transport under sub-surface irrigation for data palm trees.
my question is about the solute concentration

I worked with VarFlux1 for irrigation ( since it is subsurface irrigation) and for solute concentration shoud I put it on C1 column in the Atmosheric BC table? and should I left the default BC of solute (third type) ?

for my second application I will work with two different irrigation salinity how can I deal with this ?

thank you

Jirka
Posts: 4801
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Solute transport and sub-surface irrigation

Post by Jirka » Wed Sep 25, 2019 6:54 pm

When you assign the VarFlux1 BC for water flow, the code will take by default the concentration from the cValue1 column (see our Subsurface Line Source tutorial: https://www.pc-progress.com/en/Default.aspx?h3d-tut-22). However, if you have an atmospheric BC as well, this column (cValue1) should be reserved for this BC, and you should use either cValue2 or 3 for the VarFlux1 BC. J.

nessrine
Posts: 15
Joined: Sun Jun 28, 2015 9:38 pm
Location: Tunisia

Re: Solute transport and sub-surface irrigation

Post by nessrine » Thu Sep 26, 2019 10:34 am

thank you for your response ,

yes in my case I have an atmospheric BC

in fact the irrigation monitoring was done based on "farmer field scheduling" and they use alternative irrigation ( once they irrigate with traditional method " flood irrigation" and once they use subsurface drip irrigation). So in this case, I put the flood irrigation on atmospheric BC column with CValue 1 for irrigation water concentration and VarFlux1 BC with Cvalue 2 for the sub-surface drip irrigation. I do not need to change some codes ? or it is by default

thank you again

I'm new with Hydrus 2D/3D I used to work with Hydrus 1D

Jirka
Posts: 4801
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Solute transport and sub-surface irrigation

Post by Jirka » Thu Sep 26, 2019 2:23 pm

The code will always assigned as default cValue1 to all boundaries. You need to overwrite it with cValue2 and cValue3. Simply pick the Cauchy BC, overwrite the boundary, and you will be required to enter a code (pointer). That should do it. J.

nessrine
Posts: 15
Joined: Sun Jun 28, 2015 9:38 pm
Location: Tunisia

Re: Solute transport and sub-surface irrigation

Post by nessrine » Mon Nov 04, 2019 3:53 pm

thank you for your response
it was very helpful and I solved the problem
however now I'm facing a new problem


I'm using Hydrus 2D/3D to simulate water flow and solute transport problem under irrigation.

the irrigation method used in this work is subsurface drip irrigation and surface submersion irrigation (it is like a surface flooding irrigation )
( 2 time per week subsurface drip irrigation and one time per month surface submersion irrigation, note that we are following farmer irrigation.
my question is
should I put variable flux1 for subsurface drip irrigaton and Varflux 2 for the surface irrigation ? or the volume of submersion irrigation in the ATM.BC column ?
I have only daily climatic data , and if I put the volume of submersion irrigation in the ATM.BC column => the model diverge and ther is over flow
SO how can I deal with this ?

my domain is 3 m * 3m

thank you

Jirka
Posts: 4801
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Solute transport and sub-surface irrigation

Post by Jirka » Mon Nov 04, 2019 5:20 pm

HYDRUS BCs are always in fluxes (constant or time-variable) or pressure heads (constant or time-variable), never in volumes. J.

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