Look at a floodplain and you can see the ghost of every old channel.

Not from the ground. From the ground it's a flat field with a creek at one edge and some low wet spots nobody plants. But from a plane, or from one of those satellite maps where somebody has turned the elevation up so the contours glow, the field is covered in curves. Arcs and half-loops and crescents, nested and overlapping, faint as fingerprints. Every one of them was the river once. It went that way for a thousand years and then one spring it did not, and it left the shape behind.

I cannot look at these without feeling something I don't have a good word for. Not sadness. Something nearer to recognition.

Perfect memory

Toni Morrison said, in a talk about writing, that all water has a perfect memory and is forever trying to get back to where it was. She was talking about the Mississippi, and about how "flooding" is the wrong word, the river isn't invading the land, it's remembering. It's going back to the room it used to live in.

I did not understand this until I saw it. A creek near where I grew up, a modest one, ankle-deep most of the year, ran down the middle of a wide grassy valley that was much too big for it. That made no sense to me as a kid. Why was the valley so wide? Then one March it rained for four days and I went down to look and the creek was gone. In its place was the valley, edge to edge, moving. Every low curve that had been grass was water again, and the water knew exactly where to go, and it went there without hesitation, the way you walk through your childhood house in the dark.

Then it went down and the creek was a creek and the grass came back and you'd never know. But I knew. The valley was the river's memory, and the river was the small piece of it that stayed awake.

What we build on the ghosts

The old channels are the softest ground. That's why they are visible, they are lower, wetter, made of what the river dropped. And they are, for the same reason, where people build. Flat. Close to water. Nothing on it yet.

There is a town I know that's laid out in a curve nobody chose. The main street bends for no reason, the lots behind it are odd shapes, the church is at an angle to everything. Someone in the 1800s built along the bank of a bend that the river had already left, and then the river left further, and the road stayed, and now the town is shaped like a river that isn't there.

Every so often the river comes back to check on it.

I think about this when people talk about building on floodplains as though it were stupidity. It's the same thing that makes you fall for the same kind of person twice. The ground is soft and level and it looks like it has always been that way, and you can't see the ghost unless you are far enough above it, and nobody is ever far enough above their own life.

Oxbows

The prettiest of the ghosts are the oxbows. A river makes a loop, the loop gets so long that the neck between its two ends narrows to nothing, and in a flood the river shortcuts across and abandons the whole loop. The loop stays full of water for a while, a lake shaped like a horseshoe, and then slowly it silts up and grows over and becomes a curve of slightly different trees in a field.

The river does this because it's impatient. The loop was too long. But the loop was also the most beautiful part, the widest swing, the place where the river had gone farthest out of its way, and it's the first thing to be cut off. That's a fact about rivers and it's also, I'm fairly sure, a fact about people, and I'll leave that there.

You can find oxbows on any big river map. Dozens of them along the Mississippi, all the same shape, all pointing the direction the river was going when it left them. A record of every time it changed its mind.

There's a photograph I keep coming back to, an aerial of a river in the Amazon basin with something like forty abandoned loops around it, each one a slightly different age, the newest still blue, the oldest just a darker green in the forest. It looks like a signature. Like the river signed its name across the country, over and over, and each time the hand was a little different. Nobody took it as art. It was a survey photo. But I've had it as the background on a screen for years now and it's the thing I look at when I'm trying to remember that leaving is also a way of writing something down.

Walking one

I went and walked one, once. An old channel, not an oxbow exactly, a long curved depression in a state park where the interpretive sign said the river had been until about 1850. It was dry. It had big trees in it, bigger than the ones on the higher ground, because the soil was better. It was cooler. The air was different. It was, in every way that didn't involve water, still a river.

And I had the feeling, walking in the bottom of it, that I was inside a memory that wasn't mine. That the ground remembered something and I was walking through the remembering. The trees knew. The birds seemed to know. Only the river had forgotten, and it hadn't forgotten, it was just a mile to the east now, waiting for enough rain.

The thing it does

So here's what I've come to think the river does, and why I recognize it.

It moves. It can't help moving. It's always looking for a shorter way, always cutting off its own loops, always leaving. And everywhere it has ever been, it leaves the shape of having been there, pressed into the ground, softer than what is around it, and that shape is the memory. Not in the river. In the land. The river doesn't carry its past with it. The past stays where it happened, and the river goes on, lighter, and every spring it comes back and fills the old shapes for a few days, and then it leaves again.

That seems right to me. That seems like the only way to carry a past you can't carry. Leave it in the ground. Go. Come back when it rains.