A reasonable search didn’t find this one, even with help from the hint. Either it’s been consumed by the wild undergrowth or else I just couldn’t lay an eye on it.
Came down to the river to launch my partner’s brother on a swimming expedition (pictured putting on his wetsuit) downstream and to triple-check access to my nearby new cache GC8YZKJ. Recent logs about the cache being submerged made me worry and I spent some time looking too-close to the water’s edge, but as soon as I expanded my search I caught sight of it immediately. TFTC!