HP-1 concentration values using Solution_Spread?

The HP1 code incorporates modules simulating
(1) transient water flow in variably-saturated media,
(2) transport of multiple components, and
(3) mixed equilibrium/kinetic geochemical reactions.
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jason000
Posts: 5
Joined: Thu Mar 27, 2008 5:13 pm

HP-1 concentration values using Solution_Spread?

Post by jason000 » Mon Apr 07, 2008 8:07 am

I am having some trouble with what seems to be the transmission of some concentrations values from my Phreeqc.in file into Hydrus 1D. I am using a Solution_Spread approach, similar the one used in Problem A of Jacques 2006, in that I am entering my initial concentrations on a per node basis. After running the model, the Phreeqc.out file is showing the correct concentrations, however NOD_INF.out and nod_inf_chem.out are showing 0 for Alkalinity, O(0), and N(5)-all other concentrations are ok. I am not sure what is causing this problem or how to solve it.

diederik
Posts: 52
Joined: Fri Mar 10, 2006 7:57 am
Location: Belgium

Post by diederik » Wed Apr 09, 2008 3:21 pm

There are some inconsistencies in your input files

Alkalinity can not be used as a component to be transported. You should use C(4). Alkalinity is used by phreeqc in the initial calculations (and printed in the solution composition) and is then reported (during batch or transport calculations) only in the description of the solution. To ask for alkalinity in the output file, you have to use the identifier -alkalinity in selected_output.

-The fact that you have O(0) and n(5) zero in nod_in_chem.out are due to the wrong choice of components in defining HP1 components in the HYDRUS GUI. When you look at outflow.hse file, you see that O(0) and N(5) are not zero.

-The definitions of the HP1 components should be done more carefully. Follow these rules:
-always choose Total_O and Total_H (corresponding to O(-2) and H(1) not in H2O)
-Alkalinity does not work, you have to choose C(4)
-For redox elements, you have to include the valence state: U is not ok (it will not be recognized by HP1, and no U-concentrations will be transported), you have to define U(6), ... also for S, N, ...

-for defining initial concentrations: if an initial concentration is 0 (but present in the inflowing solution), you have to give it a very small concentration (e.g. 1E-20 mol/l), otherwise it will never be recognized by HP1 (e.g., your P).

The concentrations in nod_inf.out are total concentrations corresponding to those you defined as HP1 components.
The concentrations in node_inf.out are controlled by the definitions in the selected_output statement.


Try to make your input again. You can always send it to me for checking (maybe with a short description of what you are trying to do)

greetings,
diederik

jason000
Posts: 5
Joined: Thu Mar 27, 2008 5:13 pm

Post by jason000 » Tue Apr 22, 2008 6:00 am

Thanks so much for your help Diederik.

Just as you said-it was just a matter of using the correct component definitions in the HP-1 dialog. Everything is working fine for now.

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