Denver Metro - Drainage issue - who do I call?

[Cary P.]

I have some garden level apartments that have a cement slab at the bottom of the exterior stairs with a drain hole in them. The drains are not tied into a pipe system from what we can tell.  It appears to be one of those drains that has a gravel bed instead.  The building is 50+ years old and some of these drains are not working.  Who do I call for repairing this type of problem?  A landscaper? A sewer guy? Is there a type of contractor that specializes in these types of drains?  It's not a french drain that channels out to somewhere else, it's just supposed to drain into the ground through this clogged up gravel bed.  Everyone I have talked to says they don't do this kind of work, but cannot recommend someone who does.

Thanks!
Cary