from the interview
"that the money was deposited kind of in the middle of the bar and not near the upstream or downstream end. That’s interesting."
that's a good point. One could argue that might mean bulldozer spreading may be a possible way to get it to the middle of the bar (in spoils being spread)
another good question/answer:
Q. Have you ever experienced finding buried paper—currency, magazine, documents, etc.—along the Columbia or any beach whereby it is apparent that the paper was buried by wave activity alone.
A. We haven’t come across much paper, honestly. Mostly, we find tires, we find styrofoam, and we find plastic. In the multiple collections that we have done, there has been very little paper at all.