How long do snares/traps take to catch something, and how long do the creatures stay trapped?

[DagothNereviar 8]

Is it something you can put down and come back to several hours later? Or is it how crops are now where you have to keep an eye on them constantly, and if you miss the small window the creatures disappear?

Also does position matter. Can you put a small bottle trap in a small stream and have just as much chance as putting them in a large lake? I'm assuming snare traps need to be in woods, but other than that does it matter?