In your opinion, what qualifies (or omits) a small culvert for a mink set along your trapline? What makes a small culvert a good spot for a mink set? Or what makes them a poor choice?

If it is a nice little continuous stream flow not prone to drying up….set it…

Like Les said, if it has water and I'm driving by or over it anyway I'm setting it.

Definitely needs steady water flowing through it.

What would be wrong with it if it doesnt have water flowing through it all the time?

Nothing! It’s a scientifically proven fact (Mink Habitat Suitability Indexing Study) that “mink” waterways do need to have water at least 9 months of any given year to be considered mink/prey habitat. Think about WHY a mink is using the waterway to begin with, heck they can run anywhere but why would they choose the waterway that has the culvert, no water for a month, still water, or water with some sort of current, it’s all about prey! Damp, wet, or flowing, is the mink’s prey still available in the waterway that contains the culvert???

Hopefully my competition this mink season will drive right on by those culverts because there’s only room for one and that’s me! LOL

I have taken both mink and otter miles from water. Yes, they spend the bulk of their time around water, but they also will go overland, and from one waterway or impoundment to another.
If you see sign in a dry culvert, set it.