It's hard to say what they were doing in 1972 soon after the jump. the photo's below show them completely out of the jump zone searching. they are doing what appears to be a search east of the known flight path.
I am quite sure if the FBI had had confidence in a particular drop zone, they would have given that info to both Bradley and Palmer in 1980. They were asking these professionals to give their best estimate of how Cooper money might have arrived on Tina Bar - having precise drop zone data was vital to that task. Instead they are told to consider an area bounded by the Lewis River on the north, and the Columbia River on the south. That's a good sized piece of territory.
Had someone narrowed this large swath down to the lower third, both Bradley and Palmer might have eliminated the Washougal and come up with a different answer? Because in fact, Bradley says something like:
'Several streams feed the Columbia upstream of the Fazio farm. I am eliminating them due to size, or the degree of slope, or
location due to the scope of the large swath of territory specified and the forces needed to move a small package a long distance to the Columbia (as the FBI seems to want) from the northern area of the defined drop zone all the way to the Columbia. It is also unlikely that the described package would have passed through Lacamas Lake to the Columbia due to structural obstacles there that affect flow.'
Bradley is focused on large streams with sufficient volume and power to move a money package a long distance with certainty all the way to the Columbia, and then to Tina Bar, vs. a scenario which starts closer to the Columbia and closer to Tina Bar itself. Bradley worked within the parameters given him by the FBI.
We have this discussed all of this over and over at Dropzone and now here. The NWA-FBI Search Map is about as good an estimate of any 'drop zone' as it got, it seems. If Bradley and Palmer had been given different parameters I am convinced they would have focused on different solutions and answered accordingly. If they had been told: 'We suspect that Cooper bailed somewhere south of Battleground, closer to the Columbia, I suspect Bradley and Palmer would have looked for a different solution. Smaller feeder streams would have received more serious consideration, areas which are dry but fill up and flow during high water periods might have been considered. Topography as well as active streams would have been considered.
If the FBI had had good reason to say: 'We think 305 was clear over near the Washougal vs close to Battleground', then and only then would the Washougal have gained attention. If, Bradley had been told: '305 flew a straight line between Toledo and the tip of Hayden Island', then Bradley's focus would have changed to that looking for streams and flow opportunities which could supply money to the Fazio property from that flight path assumption.
The data people are given usually plays a role in the solutions people come up with.