This shot was taken in 2007 during the second day of the 115-mile Corvallis to Portland Row (CPR) at the Willamette Falls locks. The next year, the locks were closed. Last year, there was too much water in the Willamette, so CPR was canceled.
This is actually a small fraction of the number of boats in this particular chamber of the locks at that moment. To fit, boats had to arrange themselves creatively. Most of these folks had rowed roughly 105 miles so for some the break at the locks was a welcome respite, while for others it simply delayed the finish (and getting off their seats). As is possibly evident in the photo, patience and camaraderie were in abundance.
It turns out that the Willamette Falls Locks are "the oldest continually operating multi-chambered canal and navigation lock system in the United States." This is according to a historical web site that is urging people to participate in a Lock Fest on June 18th of this year (2011). You can be part of a flotilla to descend through the locks. Funding for the operation of the locks is a perennial challenge, so this opportunity may not exist much longer.