Bubble-up drains are the exits for the many variations on the french drain used throughout golf courses. In my experience, they seem to be used most commonly for preventing flooding in bunkers, but other features around the golf course as well.
Bubble-up drains rely on gravity to send the water down grade, where it can slowly seep back into the earth in an lower traffic area, often near tree lines. In cases of sever weather, the bubble-up will also act as a spillway to prevent floods. Much like the spillway sinks have (the little hole normally under the faucet), because the high point of bubble-up is below the bunker, water should continually spill out the bubble-up (why its called a bubble-up) rather than flood the floor of the bunker.
Once the sub-drainage in our bunker has been installed so all the water collects at a low point in one of the outer corners, the water must be transported through a solid pipe to our exit. In selecting a proper location for our bubble-up one must consider 2 things. First, grade. The very top of our bubble-up, usually marked by a 12 inch plastic green vent camp, must be below the low point in the bunker it is draining, where we switch from perforated pipe and pea gravel to solid pipe. Second, we try to find a spot of relatively low traffic, where a little extra water during a storm wont hurt as much, and where the drain itself is less likely to effect play. In the northeast, it normally means tree lines.
Sizes can obviously vary, and installing a few breaks in the pipe, where vents can be tapped into and clogs can be blown up are always a good idea.