The title says it all - which is your preference. I am usually a pocket or blind setter away from the road for a couple reasons but this upcoming season has about 25 bridges that I can set. My options are conibers on the bottom or a platform and foothold on the surface. I don't want to set both (TE and BE) due to theft, one or the other on both sides of the bridge/culvert.

The water is anywhere from 6-24 inches deep and I'm not expecting ice.

I’d go a foothold on the edge of the walls I think it will improve your numbers.

TE all day long!

If your worried about theft, the TE edges would be out. Unless you're just worried about loosing two traps at once.

If theres food at the bottom of the culverts, might lean more towards the BE. Those water depths, TE might do better and try to find trails that go over the bridge.

Get some cheap #1LS at the convention if worried about thief. Remember, you can't catch fur if you set zero traps.

I'm not worried about theft, I just don't want to set both a TE and BE on each side and lose four traps, especially when I'm catching $4 rats.

Blind sets

Nor should you need too, unless as SNIPERB mentioned, there is prey habitat on the bottom causing the mink to hunt. If there is no prey habitat I suggest capitalizing on a mink's (an rat's) inherent behavior of swimming on the surface when there is overhead cover.

I tested this theory 2 consecutive years on several old, concrete-walled bridges on my line. I built a TE trap holder that allowed for me to also set a body-grip directly below making for a TE on top and a BE on the bottom. None of these bridges had any prey cover under them and the catch ratio of the TE completely blew away the BE in mink AND rat catches. In my experience, there are far better BE set locations away from the bridges.

I do this. It always seems like the bottom produces better for me. I thought it would be the other way around but this is what I find. We cannot set the bridges here so this is out in the open with no cover.

A brick with a 110 wired to it sets nicely along the bottom and it's hard to see




Sometimes the grassy trails outperform these sets for me. But my terrain is different than yours. We have a lot of flat land with grass.

This is kinda difficult to see because of the clear water. But, the loose jaw it tight to the edge of the culvert. I used some rock to build it up and that topped it with a piece of sod.

This particular spot is good for 10-12 rats and 3-4 mink each year...before it freezes. Quick and easy to check...really easy to steal.

Catch them before thy get to the culvert.
I've seen where rats will shy away from an exposed BG. And lots of times In shallow water the rats will swim on the top when going through a culvert. Now If that culvert Is full to the top then the rats and mink will swim on the bottom. And of coarse you will find In some situations the mink will take out before the culvert and cross the road.

A baited / lured pocket set, set up with a #2 or a 11/2, made about 10' or so from the mouth of the culvert would In my mind catch you more fur and with less work.
But of coarse then your going to have to deal with coon.

Always amazes me how diffrent areas get such diffrent results.Up here in northern Maine a mink trapper setting baited sets will starve.Oh you will catch a mink or two up here but will catch many more mink with blind sets.Then I read out in the midwest and south pocket sets are the way to go.Go figure.Very interesting.

A mink spends more time on dry land then It does In the water.

Depends on where they are.Around farm country alot of time on dry land.In the deep woods not quite as much on dry land at least up here in northern Maine in the woods.Then again up here in the woods you can't spit but hit a stream or body of water.

Thanks for the comments. I set a couple bridges this season and split 50/50 TE with a 1.5CS and BE with a 160, the TE way outperformed the BE.

I was looking for others opinions and experience before I tainted the comments with my experience. The bottoms are pretty rocky around here so I think I'll make some TE rods on plates and try them out this season.

Here is what I made out of scrap for my TEs with homemade thumb-screw for adjusting for water fluctuations. If you can put the trap against a vertical surface they will work.

This design was built with using over-turned sod in mind.

That above should work good

Seldom - I like that, should be a lot lighter than a RR plate for a foundation.

On those shallow water steel culverts I would use a homemade sand bag to stabilize and bed the trap.

For those that use a TE system In those cement culverts why not just In the off season go around and use your cordless drill to drill some holes In the wall and then set a anchor so you could bolt some type of stabilizer to the wall.

But I still think you can catch the majority your rats and mink before they get to the culvert In a blind set or pocket set.