exchange river/groundwater

hello,
I am using Feflow to simulate the exchange between River and the groundwater in 3D ,but:

- I don't have information about the thikness of the colmation layer,
- How can I take into account the geometry of the river in my mesh
- the river cross many slices , how feflow  compute the flux then?
Any documentation/articles may help me !!!
Thanks.

you will find the pdf. 

Hi Thierry,
for this I think you should try transfer node as boundaries conditions, this make you able to modelling a potential clay layers between the rivers or the GW.
Cheers,
Robin