[Boston, Massachusetts] Looking for a partner to snorkel or SCUBA rivers with

[FreeRangeAsparagus]

I get the majority of my bottles from the Charles River. My usual spot is seemingly starting to run out. I guess it was bound to happen after 8 years, but it's still sad. I'd like to continue dredging bottles from rivers but I'm unfamiliar with the process of finding new spots and would love some help and a partner to go with.