Upon consideration, I am all for the street signs. I think that is a better idea than the ropes. In fact, I don't think we were talking about stringing ropes everywhere. I think we were just talking about running one rope from, what do we say, 30 ffw "down the wall" to the silo.
In the larger picture of street signs, I would propose placing no more than 4 to 6 "street signs" in the park. I believe any larger number of street signs would simply clutter up the water. Besides, we must still be considerate of some of the goals of scuba diving. For instance, if there are street signs posted everywhere, then where would the challenge be in underwater navigation? So I don't necessarily want to post street signs everywhere; but posting between 4 and 6 signs at certain strategic locations is kind of a cool idea.
Might I suggest that we discuss some standard convention for placing street signs? I would suggest that all street signs be placed at a depth of 30 ffw or be placed 5 ft off the bottom, whichever depth is the shallower. Such a standard would allow divers to know exactly where to be in the water column when searching for a street sign.