and one more complication, I think. 
The money must be buried fast so as not to be seen. Otherwise the find date might have been 1974? 1972? 1971? Could the tides have supplied enough material to convey and bury the money on the same day?
Please remember that I am from the east coast and have never been to Oregon, Washington, or for that matter; Australia (it does look lovely this time of the year though). With that being stated, I'm asking the utterly stupid question of "was Tena Bar even in existence in November 1971?"
Actually, that isnt a stupid question at all!
The answer is: yes and no, both. Look at Tina Bar in USGS photos over the years. The answer is: without replenishment T-Bar wouldn't exist at all. The dominant natural force at work on T_Bar is erosion due to south-to-north river flow and seasonal erosion. This means that on average, reverse tidal flow has supplied no material to Tina Bar over the years that stayed, and that would include Cooper money and other debris.
Things arrive on Tina Bar from known current vectors from the south, with normal river flow pressure. That low pressure lagoon between Caterpillar Island and the Fazio property helps direct material on to the Fazio property.
So essentially, Tena Bar is a hodgepodge of collected materials? It sounds like they come from all over. Basing off of that, I realize that the dredge theory seems to be a popular one however, would there be a chance that the money (and the bag) became dislodged somewhere else and found its eventually landing spot?
Now I am not suggesting that the whole "wash-down" theory but I am suggesting a different twist. Ill try and explain. So in Baltimore area in the 60's and early 70's, they had significant issues with companies dumping who knows what into the Chesapeake Bay. Construction companies, chemical companies, everything. I guess people were not as environmentally aware then as they are now...or the laws were a lot less strict.
I would also reasonably assume that in the 70's and early 80's there probably was a huge construction boom in Washington. So if some people do not like the dredge theory, what if I pose the idea that some construction company was building something and digging up earth. They never checked the stuff they dug up; they just dug it up, threw it into a truck, took it to the river, dumped it in, and called it a day. The money bag was in the area that was dug up (hell, poor DBC's bone could have been right there with it too), loaded into a truck, taken to the river, and benignly dumped. The guy running the shovel didn't notice, the guy in the truck did not notice. Money goes into the water, winds up at Tina Bar, more debris comes in, buries it and so on.
While it is rudimentary, it sort of provides a little solution to the people whom say "well if he didn't land it in the water and died, why was nothing ever found?" And if something like that happened...good luck with all the other who was he's and where did he lands...yikes!
