I heard the rocks rolling in the river last night. My house is right on the Provo River, about 150 feet away from the high water level. When the river really gets roaring, the rocks in the bed are thrown around and smash together. Sometimes it’s a soft rumble. Other times, it’s a loud “clunk” that can be enough to wake me up. It takes a pretty big flow to get the rocks moving. Last year, I don’t think I heard more than a few mild crashes. I suspect that before this runoff is over, it will sound like a bowling alley out there.

The dirt road that connects my house and several others to the highway is a flood control dike the federal government built as part of the Duchesne Tunnel project. The Tunnel, miles upstream of me, intercepts water that would naturally flow to the Colorado River and brings it under the Uinta mountains to the Provo. I vaguely remember it being built. I wasn’t allowed to venture toward the river alone. I grew up free range, but not feral. Oddly, I’ve become the institutional memory of that project. Everybody involved in the construction is long gone. The river management agency occasionally calls me with a question about the construction. The only clear memory I have is that the machinery was the super-sized version of my Tonka Toy construction set, and very cool. The recollections of a 4-year old are not very useful.

Anyway, in all those years, the dike has held and I’ve never had water on what is now my yard. Not even when the Trial Lake dam burst years ago. I was away for the weekend, and came home to find an island in front of the house that hadn’t been there when I left. But the yard was dry. Still, the house is designed so a little water in the ground level garage isn’t a serious problem.

Even without the occasional upstream dam break, the river is always changing. Those crashing rocks rearrange things. Islands come and go. For 20 years, we had a sandy beach on the side of the river. And then the one year it was gone and replaced by a new channel of swift water. The rocks move in singular clunks, then something will break loose and dozens will clatter across the bed of the river. Between the dike and the normal high water level, I used to have a patch of yard big enough for a picnic table. That land is gone now, and the river is nibbling at the few remaining trees lining the bank. I’m assuming a couple of them will go before we’re done.

The changes in my lifetime are significant, but nothing like the geologic time frame. I don’t understand the geology here. The valley is made up of sedimentary cannonballs, rocks polished and ground round by eons of rolling. Well-drillers hate it. The cobble rock is a hundred feet thick or more. It doesn’t make sense. The fill ought to be the same material that would wash down from above, but it’s not. The river a few miles upstream in the Uinta mountains has a hard granite bed, and then hits the valley filled with the sedimentary cobble. There’s a sharp line between the two. The cobbles aren’t made of granite. They had to come from somewhere else, maybe even before the Uintas erupted from below. When you get talking about mountain ranges appearing, it’s possible that things flowed entirely differently back then. 

Rocks aren’t the only thing on the move. Whole trees, sometimes 80 or 100 feet tall, come crashing down, root balls and bird nests still attached. The highway department has a huge track hoe parked at the bridge just in case something gets stuck and needs to be pulled out before it takes the bridge with it.  It’s only sort of reassuring; great that they are on it, disconcerting that it seems entirely necessary.

The evening dog walk up the canyon parallels the river. There are places where huge boulders create rooster tail rapids squirting skyward, with downstream holes that must be several feet deep. The channel upstream of the bridge is braided all over the place, with several branches competing for primacy. There are beaver dams in some of the side channels and the water is everywhere, flowing out of the woods then falling back into the channel. Logs get rearranged, piled up one day and gone the next. Once the bridge forces it all together, it more or less stays as one stream. Above the bridge, it’s different every day.

In March, the ice breaks up in loud rifle-shot cracks clearing the way for spring. In August, this violent, rock-throwing river becomes a tiny little stream. I can walk across it, stepping on loose rocks, without getting my feet wet. 

The absolute power of it is amazing to watch, over the course of a lifetime in a very specific spot, or through geologic time shaping canyons and mountains over millions of years. Lying there in bed at night, I can hear geologic clock ticking and the world being sculpted. The rocks are rolling.