Hi there,

I have a question understanding the modeling of a river. Let's say we have a river as an outer model boundary in a 3d-model with ten layers, all slices are horizontally constant. So for example the rightern model boundary is the river. River bed in reality would be located within the second layer of the model area. Top sliced is phreatic, model is unconfined. I would like to connect the river with the aquifer via fluid transfer bc. with constraint (head = river bed). To make it simple, let's say river bed and even the head in the river is constant within the model area.

--> So do I use the fluid transfer bc on all slices? Or just on slice 1 and 2? Or in general, all slices from top slice to the river bed, but not below??

I guess I shouldn't use the bc on all slices, coz results show an outflow from my model below the river bed (below layer 2, where the river bed is located) in that case. I expected a vertical flow towards the river in the lower layers, and not a horizontal model outflow in those layers.

The flowfield in cross-section corresponds to my expectation, if I use the bc only on slice 1+2.