Boundary conditions and initial pressure heads

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Posts: 5
Joined: Mon Apr 08, 2019 8:00 am
Location: Sweden

Boundary conditions and initial pressure heads

Post by theoden » Mon May 13, 2019 8:08 am


Once again I have a question that I think is on a very basic level. I am trying to model infiltration of irrigation water (and precipitation) through an (initially) unsaturated soil profile, and how nitrogen (introduced as urea in irrigation water) is spread. However, when running the model I get results that are a bit confusing, so I'm thinking that I set BC and intial values wrong. My settings:

Upper BC: Atmospheric BC with surface layer (max h = 20 cm)
Lower BC: Constant pressure head (this should represent the groundwater level)

Initial pressure heads: 0 cm at bottom, rest is left at default -10000 cm

Precipitation is entered as metreological data + irrigation of 20 cm/day every fourth day where the concentration of urea (cTop) is 0.1.

Are the BC reasonable? Is it the intial values that must be further specified?
Thanks in advance!

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

Re: Boundary conditions and initial pressure heads

Post by Jirka » Mon May 13, 2019 2:31 pm

Your BCs seem reasonable. However, your IC does not. You would have an early fast inflow into the soil profile from the bottom. J.

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