The river is not a static thing

The Red Deer River is estimated to be about 10,000 years old. In the relatively few short years that Otter Rafting Adventures has been around - 30 years - one can see it is nothing compared to the life span of a river. When travelling down the river we can see the marks of wear on rocks that are easily 10 meters above the present river floor. One wonders how long it's taken to erode the river bottom down to its present level from up there. On the left side, half way up of the top picture, you can see how at one time the river was scouring the rock, eating in and down.

Erosion, while something that happens in a gradual manner, can also take place quite quickly over a matter of days. I have seen the river move 100 meters across the valley floor in 5 days. The new channel contained all the water flow while the old channel, not recognizable, was filled in with gravel that was 3 meters higher than what it had been only days before.

When we look at the river we only see that the water is flowing down hill. But there is also another flow that is happening. This is the movement of the solid materials down hill that are being swept along with the water. It is like sand blasting but using water as the carrier rather than air. Unlike sandblasting, it is made up of many different sizes of particles and different materials, from fine dust to boulders.

The amount of wearing down of the valley floor that is occurring can be seen by the color of the river water. There is the rushing, murky, chocolate colored water in the spring, flushing out the materials that have accumulated by the freeze and thaw of winter, to the clear water of mid summer when only the finest particles are being carried by the moving water. When I have been rafting in the spring, I have heard the sound of sand and grit, suspended in the water, striking the bottom of the raft. You also hear the clacking of rocks beneath the raft as they are rolling downstream, propelled by the water. All this moving material is breaking down into smaller pieces as well as chipping away at the river bottom.

And to where does all this lead? A lot of this erosion ends up being clay. Check out www.otterpottery.com for the results.