I have been fortunate to have had opportunities to work on a number of substantial site utility projects on school campuses.  On these projects, utility lines criss-cross each other in a three dimensional matrix that can be hard to decipher.  And, of course, In many jurisdictions its not enough to "miss" the other line by a few inches.  Often there are minimum separations and minimum pipe cover based upon the type(s) of utility, the pipe material and the soil conditions, so its not as easy to put this puzzle together as it may sound.  

I applaud those Civil Engineers who take the time to identify each location where a new utility line crosses another new or existing utility line (if known) and calculate the separation between lines. Not only does it show that they are thinking about how this puzzle goes together, they show consideration for their client and the project as a whole.  Its no fun to find a way to make your sanitary sewer and storm drain lines cross the water lines while still maintaining their slope and minimum ground cover.  And, its expensive to try to solve this puzzle when you have one or more excavators with crew waiting to hear the answer.  So, hats off those CE's who solve the problem on paper before we try to lay the pipe.

Now, if I could just get those Civil Engineers to work the power and telecommunications conduits into their piping solution...