A situation has come to my attention that I feel needs moderator intervention.
Drawing attention to the situation might make it worse, so I would like to speak privately to a moderator. Is the some way to do this?
Another way, leaving no publicly visible trail at all: flag a post (on of your own or one that is involved in the matter you want to discuss) and state you want to chat with us privately. We'll then open a private chatroom as AIQ says.
Yet another way, since you have 100 reputation, is to create a chatroom and invite one of the moderators. That moderator can then make the room private.