Is there such a thing? I played a course the other day where there was a drainage ditch that was clearly man-made (i.e. dug out, not naturally occurring), about 10 yards to the side of the green in a weeded area. My wife's stance was interfered with by the ditch. The area was not marked by any stakes. I wasn't sure whether she got relief or not. In checking the rules I find this:
A "water hazard" is any sea, lake, pond, river, ditch, surface drainage ditch or other open water course (whether or not containing water) and anything of a similar nature on the course . All ground and water within the margin of a water hazard are part of the water hazard.
Obstructions — Anything artificial, including artificial road surfaces, except:
a) Objects defining out of bounds;
b) Any part of an immovable artificial object which is out of bounds; and
c) Any construction declared to be an integral part of the course. [The ditch was not declared as such.]
I'm inclined to say that even though the area wasn't marked, the ditch was a water hazard by definition - but could it also be artificial? Decision 26/4 states that a man-made reservoir is considered a water hazard, so I'm guessing that would imply a man-made ditch is as well, but it's not clear to me.
In general, which definition takes precedence, that of a hazard or that of an obstruction? I.e., if there's an immovable artificial obstruction within a hazard (a fence, perhaps), do you get relief from it? (I can find no rule that states otherwise.)