This close-up of the rapids was taken a bit upriver from the previous one and close to the small falls, which churns the water in the right foreground; the rapids above the falls produces its own white water as the river spills past with a lovely noise.
As best as I could ascertain, what one sees in the river here are not boulders, but pieces of bedrock that have not yet been ground down by the powerful waters. The lack of vegetation on the bedrock on the shores most likely attests to the great blocks of melting ice pushed along by the much higher waters and the much more powerful flow that must spill through this constriction during the spring run-offs.