Retaining wall vertical vent?

Hi members,

Here's a photo of a vertical vent of a retaining wall. It's 4 inch PVC . There is one every 50 feet along this wall. When you look down in the vent you can see the drain rock at the bottom of the back side of the wall. I want to convince the land manager of this nature area to allow me to cut the vents flush with the dirt and cap them. I assume the original installer heard of the need to horizontally "vent" (provide horizontal drainage to daylight) every 50 feet, and then assumed the word "vent" means vertical. Can anyone think of a possible reason these vertical vents were installed? Am I right that they're useless? They are an eyesore. Thanks in advance for your advise!

 

Where is your lot line? If it is on your side then you can do anything you want, if not hide it with a bush. Or cut it down and cap it off without cement. If anyone squawks, just replace the pipe with a coupling. If it is not connected to any sanitary pipe, there are no plumbing codes addressing drainage pipe. If this is on a long slope, they could be acting as an overflow. That is if the lowest end it plugged up or it cannot handle the load of drain water, it allows the water to back up and onto the ground.
The only time I've seen a vertical drainage pipe is with a french drain system where the vertical pipe was used to prevent the window wells from filling with water.

 

My lot isn't near the wall, which is in a nature area where I walk.
Thanks for the idea that they might be for overflow release. The wall is on a very long slope. Some vents extend five feet above the top dirt surface, so they're quite high, but maybe that's to keep kids from dropping debris in.