At some point it comes down to considering what's involved with each scenario. I just do not believe a bundle of cash is, by some natural manner, going to end up washing ashore on Tena Bar, self burying, then get discovered nine years later. I think that the odds of such an occurrence are one-in-a-trillion at best all things considered.
Likewise, the dredge theory strikes me as equally implausible. It's just too fantastical in my mind.
That leaves only one scenario; the money was buried by human intervention. Of course, this assumes that the Ingram's were telling the truth.
Disagree, IMO, your scenario is highly speculative and stretches reason and logic.
Requires..
Moving the flightpath,
Cooper buries money close to landing zone to retrieve later,
Buried on a sandbar near the river, extremely poor site selection for purpose.
The most plausible route is the money coming from the River. I don't really like the dredge, but that is irrelevant, the $200,000 question is how did the money get into the River upstream of TBAR.
BTW, I was looking closely at the holes in some of the bills and they look exactly like insect holes. I agree with Kaye that some were made from bacteria, but not all have that dark edge..
Perhaps some of the holes are from sand or grit that got between the bills and the abrasion created the holes during wet/dry cycles.
and if the sand at a higher volume had infiltrated the edges of the packet that abrasiveness may have caused the unique shape of deterioration.
.