Placing culverts away from water prevents them from rusting out thereby saving the taxpayers a lot money. It's the new green environmentally conscious way of stretching our resources.
I hear next they're planning to build a hydro-electric dam in the Mojave desert to save a hundred million dollars on concrete. Since there won't be any water in it they can just build the shell.
I agree water can be hell on dams- my ol stompin grounds when I was a kid.