I'm getting the feeling that since this was a fairly recent (1979-1981) man-made lake, they did know what they were covering up by damming the river. Like you said, Joe, plenty of property papers on record.
A woman in the area just finished self publishing her inquiry into the history of the lake. Of course, this was completed prior to the college student find from the drought. Part of it can be read online at
Lulu. She was also featured in Fridays paper
HERE, which has some history of the lake but no mention of the find reported just a few days earlier. ???