Meaningful ways to volunteer and network?

I want to volunteer to gain some more experience and hopefully network… have any of you ever gone this route and found success? Where did you volunteer?

For reference I live in Maryland, and so far I’ve been looking at the NRCS, Maryland DNR, and the nature conservancy for spots. I specifically want experience with water and soil, and would like to help in a way that’s different than picking up garbage on the banks of a stream (but of course, I would do that too). I’ve seen someone once say they even volunteered for a biologist in a government agency. Where can I find opportunities like that? I want experience with environmental monitoring/sampling, even if I’m just shadowing someone, and of course I don’t expect to get paid for any of this. Does what I’m imagining even exist? For reference I just graduated college, so I’m no longer a student