Improve validation xsections + cleanup

[dbrakenhoff]

Add check for gaps in xsections and add check for correct number of z-values for semi-confined models.

• cleaned up the inits for both submodules, and adjusted notebooks accordingly.

[mbakker7]

Maybe also look at Issue #110 ?

[mbakker7]

Am I correct to understand that timflow doesn't nudge anything, but suggests to nudge when elements (BCs) coincide? If so, I like that. If not, let's discuss.

This brings back the question of an inhomogeneity boundary where one or more (or all) layers are constant head of impermeable/leaky. That would be useful, but we would have to think of a clear way to define that. Something to consider for another issue (there probably already is one).

[dbrakenhoff]

Yes, correct, Timflow doesn't do anything, but does raise an error, listing the elements on boundaries and a suggestion to nudge their positions.

As for your second comment, we have the issue on supporting finite domain cross section models and specifying the boundary conditions for those situations, which feels like a somewhat similar problem.

I think letting users add their own boundary elements might be too complex(?) so some kind of control through keyword arguments or extra Xsection classes might be the way to go. But this too could get pretty complex given all the options here (finite domain, fixed head, ghb, flux, or boundaries between domains with fixed heads or resistances in specified layers). Something to think about :).

[dbrakenhoff]

I should perhaps have added the element vs boundary check to the steady model as well.

Oops, I did that already 😅

[mbakker7]

Very useful addition.
I have some thoughts for an integrated element, but that will be for a new issue.

[mbakker7]

I think letting users add their own boundary elements might be too complex(?) so some kind of control through keyword arguments or extra Xsection classes might be the way to go. But this too could get pretty complex given all the options here (finite domain, fixed head, ghb, flux, or boundaries between domains with fixed heads or resistances in specified layers). Something to think about :).

What I was thinking is: We can make, for example, a River (line-sink) element where the user specifies the layers it is in, and in the other layers applies a continuity condition. That is all that is necessary. So it is an extended element, but the element itself and the specification by the user is easy. What remains to be decided is how to specify this for inhomogeneity boundaries. Maybe we can catch that for users: When an element is placed on a boundary, we replace the boundary (inhomogeneity) element by this new element. And your nudging code can be removed. Let's think about it some more. Definitely something for a new Issue.