Mulilayer Well doesn't work correct

Hallo ,

I have a problem with the multilayer well in my groundwater modell.
It is an unconfined modell area (Status phreatic). I wanted to join a multilayer well with a constrained max  hydraulic-head. If the hydraulic head is higher than 0.5 m the well should start pumping. Under 0.5 m there shouldn't be any pumping. My settings are:

capacity: 0
radius: 0.25
max h: 0.5
Extent in z-direction: From selected Join Edges (the bottom of the slice lies at -0.50 m, the top is at  1.5 m).

My problem now is that the well pumps too match. The hydraulic head has than a constant value of  around 0 m. Did I miss something?

If I change the max h from 0.5 to 1 m the well doesn't pump at all (also if the hydraulic head reaches a value above 1 m).

I would be very greatful if anybody has an answer to my question.

Best regards,
Steffi

The max option turns the (internally set) well bc into a hydraulic-head bc if the head exceeds the maximum. So if your head would be above 0.5m, the well would be replaced by a head bc of 0.5m. If your well is meant to start pumping at head values of higher than 0.5m, then 0.5 will have to be set as the min constraint.
Please note: At levels below 0.5m the will will NOT be turned off, but converted into a head bc. If factors other than the well cause the lowering of the water table, the well may even start infiltrating water to keep up the 0.5m level.

Hello,

thanks for your quick answer. I changed max h into min h but I still had the problem that my hydraulic head didn't reach the predetermined value. I noticed that the problem lies in the porosity of the soil. The first layer has a lower porosity then the second one. So that's way the hadraulic head in both layers are different. The hydraulic head in the second layer corresponds to the predertermined well constraint.

Do you know how I can't awoid infiltrating water. I find this solution (http://www.feflow.info/html/help/default.htm?turl=HTMLDocuments%2Freference%2Fparameters%2Fboundaryconditions%2Fflow%2Fwell_bc.htm) in the FEFLOW help but I'm not sure if I interpret it correctly. According to it I have to use a single well BC. Do I have to combine the BCs in the expression editor? How would the equation looks like?

Best regards,
Steffi

Hello,

at last I found my solution.
I have to assigne the hydraulic head BC a value of .5 m, then to add min-flow-rate constraint and max flow-rate-constraint in the context menu with a min flow of 30 m³/d (for example) and a max flow of 0 m³/d.