Problems with a modflow 2005 Steady-State model

[sebmeng]

I have build two modflow 2005 models, one Steady State, and the other one is Transient (with the same geometry). For a strange reason, I get wrong results from the Steady State, but rather logical results from the transient model (as a "pseudo-steady" model, where the model runs with 365 daily time steps with the average daily recharge, that whas also used as recharge for the steady state model).

With this same values, i get a distribution of heads in layer 1 that is very much above model's top:

If I do the same procedure, but in the transient model, with the same average recharge and ET, the model gets these results:

With more realistic heads in layer 1:

The model were constructed with the same geometry, and the same boundary conditions, I have double-checked both geometries and balances and they are quite OK, but i do not really know where is the underlying error. Both models were constructed using FloPy in MODFLOW 2005, using the NWT solver.

Does someone have some advice on where to look? Besides changing the solver parameters, that are nor really helpful.

Every help or comment would be appreciated!

Thanks in advance,

Sebastian