Looks like an overflow drainage pipe to me, but it seems awfully large for such a small catch basin. If anyone knows, feel free to comment in your log.
You might get muddy or wet going after this cache after a heavy rain. I rarely see any water in the pond., but it does happen. Employ stealth as needed. You might encounter canines exercising their humans or someone using the "fitness trail" that runs past here. GZ is a short walk from the parking coordinates.
Please do not log any "I forgot a pen" logs, nor any "I found it but did not sign the log" logs. A flashlight might be helpful, but not required.
Congratulations to DadTwins for FTF. Life is Good!