Another interesting tale of the Columbia River is that of The Bridge of the Gods. It was a geographic anomaly that caused a sort of dam across the river. It has many stories in Native folklore. It is now gone, of course. Even if it were still there, the damming of the river downstream at Bonneville would have certainly destroyed it. Now, there's a man-made bridge in Cascade Locks that shares the name.
There are many articles online...
[url=http://en.wikipedia.org/wiki/Bridge_of_the_Gods_(geologic_event)][b]Wiki article link[/b][/url]...I know that Wikipedia (wiki wiki!

) is notoriously inaccurate, but this is interesting.
[url=http://www.dlmark.net//gorgebogwashington.htm][b]Another page[/b][/url] on the Bridge, and its modern counterpart.
Paul Fruittrees' thread on Celilo Falls reminded me of this. I'm a huge Columbia River buff...