Free drainage with vapor flow output

[dg34]

Hi Jirka,

I am simulating water and vapor flow in a two layer soil profile with an atmospheric upper BC and a free drainage bottom BC. My goal is to approximate groundwater recharge via the water flux through the bottom of the profile. However, I am having some trouble interpreting my results.

According to the HYDRUS manual, vBot in the T_LEVEL.out file is the actual flux across the bottom of the soil profile. Likewise, in the Balance.out file, Bot Flux is the actual flux across the bottom of the soil profile. In other words, they represent the same value. However, the values listed in each file are not the same. In comparing these with the Nod_Inf_V.out file, the value for Bot Flux does coincide with vTotal. Summing vVapor and vLiquid also gives the same value. Why is there this discrepancy?

Further, it seems very counterintuitive to me that the value for vVapor at the bottom node (depth of 15 m) would be negative (outflow), and would dominate the flow processes (vVapor >> vLiquid), which according to HYDRUS, is the case. Any thoughts on why this might be?

I have attached my files for reference.

Thank you,
Dan