Here is a fascinating little video on Expo '74:
The changes that Expo 74 wrought are fascinating, someone should write a book about it. (Just kidding Bill!) The problem with this clip, as is so often the case with information posted on communty websites, is the lack of provenance or identifying information. When was this vide made? When was it aired? By who?
Also of interest is "Nez Perce Resumes Buffalo Hunt," a trailer for Arid Lands "an independent documentary film about the land and people of the Columbia Basin," and this cool documentary about Woody Guthrie when he worked for the Bonneville Power Administration to promote the Columbia River dams.