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Modflow Flow Budget -65% discrepancy (?)

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I've built a Modflow Tprogs 4 layer model.

I set up two boundary conditions: Specific Head CHD 0.8 m asl and 0.1 m asl and recharge.

I interpolate head values to Modflow Starting Heads, run the models (3 HUFs series, steady state all converging) and select the first one.

Flow Budget for All Zones


Constant heads 0.0005320032089

Recharge 0.0001837699922

Total IN 0.000715773201


Constant heads 0.0014137398358

Recharge 0.0

Total OUT 0.0014137398358


IN - OUT -0.000697966635

Percent Discrepancy -65.55175973918

What's wrong with the diffence between in and out?

Selecting the Specific Head CHD arcs, I get the following:

1 Specific Head CHD (0.8 m asl) = 0.000412

2 Specific Head CHD (0.1 m asl) = -0.0013

Why is 1 different from the Flow Budget Constant heads IN value?

Thank you for support!


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Sorry for late replay; I was trying to minimize the percent discrepancy.

I'm using PCG2 solver.

I thought that the convergence criteria was based on the flow budget.

Do you refer to Convergence Options in the Modflow menu or to Head change criterion for convergence in the Modflow PCG2 package options?

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