A branch drain accepting waste products delivered to it vertically, by gravity, from one or more similar but usually smaller fixtures, and conducting them horizontally to the primary disposal drain.
When the Minuteman III retires, the silos and launch facilities at Malmstrom Air Force Base in Montana, which oversees 150 nuclear ICBMs scattered across a 13,800 square miles, will have been buried for 70 years.
To Find America's Nuclear Missiles, Try Google Maps. Earlier this week, NPR ran a short series I did on America's land-based nuclear missiles. One diagram in particular raised a few eyebrows: It showed the location of a Missile Alert Facility, along with the silos for 10 nuclear weapons.