It's dangerous

What once was has not departed
It still remains with me
And bears evil witness
To former shipwrecks
Old wrecks lie on the riverbottoom
A muddy home for fish and crawdads
What's happened? Why am I included?

They say the river never enters
The same person twice
But once you've seen those wrecks on the bottom
You'll never believe that old saw
I sit in the mud withy my eyes popping out
I scare the fish, I hunt the crawdads
What's happened? Why am I included?

I can't remember it's dangerous