Well as 2nd or 4th kind BC?

Discussing a mysteriuos head at a well-position with the hotline, I´ve been told, that generally it is the "better" way to simulate wells by using 2nd kind BCs instead of 4th. But there is no such comment in the manual! So my question is:

So, should I generally use 2nd kind BCs for "normal" wells to avoid mistaces or are there any special cases in which it is necessary to do so? Or should I, as I´m used to do, simulate wells by 4th BC as I´m told by the manual?

Thanks for an answer!

As FEFLOW as a numerical code is based on spatial discretization, there is always an influence of the size of the mesh elements on the head at a well. This is the case for any numerical groundwater model. In most cases you will not be interested in the exact hydraulic head at the well node. In this case, you can simply use a well bc. If you want to get exact heads for such a boundary condition, the mesh elements around the well nodes should have the size of the well diameter ('equivalent well diameter'). However, in cases where you would like to study the surroundings of a well even more in detail, e.g., to determing fluxes into the well from different sides with different material properties, it might be the better option to discretize even finer and use a flux boundary condition instead.