That could be... Some kids playing on a river bank found some of the $$$ back in the 80's. The area was near where they were dredging the river. within the last 10 yrs, a parachute was found wrapped around a bridge support near the jump zone..
Having grown up in WA. The local legend is that D B Cooper shows up at the annual DB Cooper Day festivities in disguise..
D B Cooper was a misnomer.... I can't remember who, but someone added the middle initial. It was D Cooper who made the jump.
http://en.wikipedia.org/wiki/D._B._Cooper