First of all it's not a plug, it's a cap. Second of all, the picture is extremely blury. Thirdly, the pipe is too high above the water table to have any effect even if it was open. So fourthly, it's probably not there to drain water, but serves some other purpose (venting, maybe septic plumbing). Giving us a description of what rooms are near the pipe and what sort of things are in your basement near that pipe could give a hint (sump pump, toilet, shower, water heater, mainline out to septic tank/septic system).