This is the confluence with a small river with a great name: the Wasipinicon. It joins the Mississippi below Adams Island, where I slept last night.
It does the same thing as many of the small rivers I've seen, adding a visible load of silt and other suspended solids to the larger river. I no longer think these are going "downstream." I now think they're going to end up in the next dam pool, to be dredged up periodically by large fossil fuel powered equipment employed by the Army Corps.
A hundred years ago, at least some of this sediment would reach the gulf, and helped build the land down there that is now disappearing.
On the upper-upper river, a confluence was a relatively rare and pretty exciting thing. I'd take pictures of them all, react to them all, check the turbidity of the two streams as the conjoined. Now, it feels like there are too many to track, and so many of them are hidden from my view behind islands and sloughs and on the other side of massive dam pool lakes.
In the last few days the map tells me I have been joined on the Mississippi from the Wapsie (as the name of a daybeacon for barges in the area makes clear it is commonly called), Shaffton Creek, Rock Creek, Johnson Creek, Elk River (not the first Elk River to meet the Miss!), Plum River, Apple River (I wonder if people tube down it, as they do the one in Wisconsin?), Rush Creek, Maquoketa River, etc. Some of these I could see, many I could not. All of them seemed smaller than the various strands of the Miss that separate and come back together.
I feel like I'm giving them short shrift, but I can't figure out what else to do. It's a relativity thing, I suppose. Relative to the Miss at this point, most of them are just so... tiny.