srivett you are right about the round cover not falling down the m/h. In NYC, the DOT has maps of every street and each street is divided into underground lanes and these lanes are assigned for the underground utilities. Storm drains usually get the center of the street. The water main will be on one side of the street and the gas main on the other side. Some streets can have multiple water or gas mains under them. Then there are lanes for primary electric, secondary electric and for telephone and cable lines. The mains that have water in them, storm drains, sanitary sewers and water mains are the deepest, storm drains 12'-15' deep, sewers 8'-10' deep, gas mains 4'-6' deep and the shallowest are the electric, phone and cable lines. Some streets over the years have been widened or narrowed, raised or lowered. Streets in midtown and lower Manhattan are a total maze of ducts and conduits with all the electric and telephone lines. Streets that are lined with apt bldgs will have a m/h in front of every bldg.
