Problem with hydraulic head BC with constraint

Hi,
I am trying to use an Hydraulic-head BC with max. Flow-rate constraint to simulate a spring in my model . It’s an unconfined aquifer, with phreatic surface, and i’m running it in a steady state. The problem is that this BC is not working (i.e. when i run the model, the water level at this point remains high, above the topography).

In other parts of the model, this BC is working normally, but speciffically at this point it is not working, and I would like to know how to solve this problem.

Thanks.

Hi,
in steady-state the correct working of constraints ist not strictly guaranteed. They are evaluated once and then kept, as otherwise the model would very likely loop infinitely over finding the correct status. In such a case, where the spring BCs keep infiltrating water, I recommend to run the model in transient for a while. Once the correct water table is found, it might work to run scenarios in steady-state again (assuming that the conditions at the springs do not change much).

Sorry about my question, but I am new in FEFLOW. I’m triying to run it in transient, but it is taking too long. Do I have to change any other parameter in order to run it in transient or just switch to Transient in the Problem settings?

Thanks.

Never mind, i've run it for a while in transient and it worked.
But when i run it in steady-state, it's still not working.  :-\

[quote author=Peter Schätzl link=topic=20562.msg26503#msg26503 date=1498196102]
Hi,
in steady-state the correct working of constraints ist not strictly guaranteed. They are evaluated once and then kept, as otherwise the model would very likely loop infinitely over finding the correct status. In such a case, where the spring BCs keep infiltrating water, I recommend to run the model in transient for a while. Once the correct water table is found, it might work to run scenarios in steady-state again (assuming that the conditions at the springs do not change much).
[/quote]
Dear Peter,
are you sure the constraints are only checked once? The calculation time of my current model (steady state using boundary condition constraints) seems to be multiple times slower than the calculation time of a model without bcc. I would expect, that in the case descibed above calculation time should max. double. Furthermore Feflow displays the attached message (reprofiled matrix at time 0.001).
Greetings