It's not 80 dirts above ground. I have a fairly long bridge with several supports way up on a hill and that bridge hits the ground at 0 height at the end. But when I went to duplicate the bridge from the terrace to the bottom of the deed, I can't. Why? Because a support needs to be 80 dirts above water. Not 80 dirts tall. 80 above water, even water that is not there.
I admit, there are a such thing as Prairie Schooners...
but there is not...
It's bad enough that we who live on the coast need to pile up to 10 dirts at the bottom of a bridge but to be limited to bridges 5 long and under because supports won't fit is annoying to say the least.