Aw shucks, I was enjoying the fantasy. Oh well. On a heavier note, Cooper probably injured himself in his jump and was eaten by wild things. Some of the money in $20’s was found in the woods where he would have landed, by some kids IIRC. His parachute was also found, I think.
Based on the matting and the rounded nature of the disintegration, it was determined that they had washed down the river a considerable distance before reaching their resting place.
There's no report of any of the Cooper money being found by a lake or anywhere else. Just the Columbia river find.
In 2007, the FBI disclosed that one of the two parachutes given Cooper was a dummy chute with an inoperable ripcord and that Cooper had jumped with that chute, cannibalizing the working chute (probably to wrap the money to his body).
So, yeah, Cooper cork-screwed into the ground at terminal velocity, if the FBI's information is true.