Bottom flux

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SHYMA M
Posts: 14
Joined: Sun Jan 29, 2023 11:03 am
Location: India

Bottom flux

Post by SHYMA M » Sat Jun 29, 2024 7:37 am

Sir
Can the bottom flux from the soil profile be greater than saturated hydraulic conductivity of the bottom soil layer?
I am simulating water flow under paddy field, where the Ksat of the bottom layer is 1.8 mm/d. But the hydrus simulated bottom flux were greater than 1.87 mm on most of the days. could you please explain it?

Jirka
Posts: 6074
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Bottom flux

Post by Jirka » Sat Jun 29, 2024 12:45 pm

It depends on the bottom BC. If you have a free drainage BC, then it should not be larger than Ks (since only the gravitational component of the total flux is active). If you have a pressure head BC, then it depends on the pressure heads in the profile, since you will have both gravitational and pressure head components (see the Darcy’s equation) of the total flux. J.

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