## Hydrus-2D

A discussion forum for old Hydrus-2D & Meshgen. Happy Posting!
mahesh singh rawat
Posts: 3
Joined: Wed Aug 19, 2009 8:02 am
Location: India
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### Hydrus-2D

RESPECTED SIR/MAM
i m mahesh. i m working on simulation of soil moisture in a rice field using hydrus-2D model. i have all the data required but i do not know how to run this model and to simulate it. please give me some examples on this.
thanks

Jirka
Posts: 4762
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA
You can find tutorials and library of examples (these are only for HYDRS-1D and HYDRUS (2D/3D)) on the HYDRUS web site.

Jirka

Mirek
Posts: 408
Joined: Sat Mar 16, 2002 4:00 pm
Location: Czech Republic
Contact:

babakd92
Posts: 5
Joined: Tue Apr 05, 2016 2:11 pm
Location: Iran

### Re: Hydrus-2D

Dear Jirka . . .
I wanted to simulate the lateral infiltration in a furrow with 5 and 10cm water level. So I did the simulations with HYDRUS-2D. In the next step, to determine the infiltrated water in cm, I divided the cumulative infiltrated water in cm2 to the wetted perimeter in cm.Then, I did the other simulations with HYDRUS-1D and the vertical infiltration were determined. By deducting the vertical infiltration from the cumulative infiltration, the lateral infiltration was calculated.
When the amount of lateral infiltration in 5 and 10cm water level are compared, it can be seen that by increasing the water level, lateral infiltration is reduced. For example:
-Wetted Perimeter (cm): 5cm water level = 36cm , 10cm water level = 57cm
-Cumulative infiltration by HYDRUS-2D (cm2): 5cm water level = 346cm2 , 10cm water level = 551cm2
-Vertical infiltration by HYDRUS-1D (cm): 5cm water level = 7.34cm , 10cm water level = 8.41cm
-Lateral infiltration: 5cm water level = 2.1cm , 10cm water level = 1.1cm
The result is different from the reality.
What is the problem?
Is the HYDRUS-1D has overestimated? Or HYDRUS-2D has underestimated?
In both simulation, the van genuchten parameters, initial conditions, boundary conditions and etc. are equal and similar.
Best regards.

Jirka
Posts: 4762
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

### Re: Hydrus-2D

I'm on vacations and will not have time to look at this problem (which I do not think is a problem only the incorrect interpretation) until I return. J.

babakd92
Posts: 5
Joined: Tue Apr 05, 2016 2:11 pm
Location: Iran

### Question

Dear Jirka . . .
I wanted to simulate the lateral infiltration in a furrow with 5 and 10cm water level. So I did the simulations with HYDRUS-2D. In the next step, to determine the infiltrated water in cm, I divided the cumulative infiltrated water in cm2 to the wetted perimeter in cm.Then, I did the other simulations with HYDRUS-1D and the vertical infiltration were determined. By deducting the vertical infiltration from the cumulative infiltration, the lateral infiltration was calculated.
When the amount of lateral infiltration in 5 and 10cm water level are compared, it can be seen that by increasing the water level, lateral infiltration is reduced. For example:
-Wetted Perimeter (cm): 5cm water level = 36cm , 10cm water level = 57cm
-Cumulative infiltration by HYDRUS-2D (cm2): 5cm water level = 346cm2 , 10cm water level = 551cm2
-Vertical infiltration by HYDRUS-1D (cm): 5cm water level = 7.34cm , 10cm water level = 8.41cm
-Lateral infiltration: 5cm water level = 2.1cm , 10cm water level = 1.1cm
The result is different from the reality.
What is the problem?
Is the HYDRUS-1D has overestimated? Or HYDRUS-2D has underestimated?
In both simulation, the van genuchten parameters, initial conditions, boundary conditions and etc. are equal and similar.
Best regards.

Jirka
Posts: 4762
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

### Re: Hydrus-2D

I do not think that you give enough information for me to be able to follow your calculations (what you subtract from what and what you divide by what).

I'm pretty sure that both HYDRUS-1D and HYDRUS-2D give you the right answer (if you use the right discretization), which is fully in agreement with reality. They give you a precise solution of the Richards equation; they do not underestimate or overestimate the flux (as you can likely see from the mass balance error, which should be below 1%). Thus, I still think that you incorrectly interpret the results.

J.