Anabranching: From the Air

If you live on the East Coast, especially in the mid-Atlantic region, you might be familiar with the types of streams you often find there—meandering streams, with high banks full of fine sediment. They tend to erode badly, so stream restoration has become a multi-billion-dollar industry on the East Coast.

Here's the interesting bit: those high-banked streams they're restoring aren't natural.

Prior to European settlement, streams on the East Coast tended to be composed of multiple channels that were divided by islands and wetlands, with fairly low banks (also called anabranching). The wetlands tended to be highly effective carbon sinks. You definitely didn't find the single-channeled meandering streams you do today. So what happened?

In a word? Millponds. Water-powered mills dammed up rivers and streams all across the East Coast. This slowed down the streams and created spots where the sediment could settle out of the water at much greater rates than normal, producing those high stream banks.

A Millpond

Now that we don't use water-powered mills to grind our flour and cut our lumber like we used to, most of those mills have vanished over time. And most of that multi-billion- dollar stream restoration industry? It's just trying to keep the streams and rivers flowing in a manner unnatural to them.

The stream restoration industry players aren't fighting an entirely uphill battle. Some of them are starting to listen to the science. Instead of repairing the eroding streambanks, they're accelerating the process in order to return the streams to their former state.

This approach is not exactly popular yet because it involves bulldozing all the plants and trees that have grown on the stream banks, which isn't very pretty.

There's a more important lesson to take from all this: namely, that we change the world around us in ways we seldom recognize.

Many of our ideas about what nature is come from what we see around us, which is seldom untouched. And nature possesses nearly unstoppable inertia; look at the stream banks eroding now.

Nature had to wait centuries, but she’s still reclaiming her streams on the East Coast. We need to be cautious about where we build and how we alter nature. It’s best to work with her. In the long run, working against nature is seldom a winning strategy.

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Quotable

Yep, Yard Ramp Guy: Backwards we continue with the alphabet quote-off:

“Waiting for perfect is never as smart as making progress.”

— Seth Godin

Yep. That works.

Quick quiz: What's the most important resource for civilization? Let’s exclude water, which is, far and away, the most important (and would, ahem, leave me without the topic I chose to write about this week).

You’ll be tempted to say oil, but that's not even close. Nor is metal.

The correct answer? Dirt.

“Yes,” you’ll say, “dirt is literally everywhere. It's what the ground is made of, for Pete's sake. How can something so common be that important? I mean, yeah, we need it to grow all of our food, but it's not like we're going to run out anytime soon.”

Unfortunately, I've got some bad news for you but, naturally we'll first need to go back in time.

During the Roman Republic, the fields of Italy were famed for their fertility and were a big part of Rome's early conquests. And during the Roman Empire? All of the grain was shipped from the fertile fields along the Nile via the Port of Alexandria. In time, the fields of Italy were no longer capable of supporting the population of Rome; the soils had been exhausted of nutrients, with much of the topsoil stripped away.

Let's travel even further back to ancient Mesopotamia. The end of Mesopotamia's reign as the center of civilization ended due to the very thing that made it possible: irrigation. Long-term irrigation caused the salinity of the fields to increase until the fields were too salty for crops.

“But,” you’ll say, “we're talking thousands of years, here. Technology's increased to the point where we don't need to worry about that anymore.”

Nope. Doesn't work.

Sorry to be a downer, but we need to worry about it now more than ever.

Soil is fragile stuff that can take decades—sometimes centuries—to form. Our ancestors needed millennia to master agricultural methods that preserved the soil, and we've largely discarded their methods.

Terracing, contour plowing, no-till farming, use of compost and manure: those are no longer in the playbook for most of our farms, especially the largest ones.

Tractors, nitrogen fertilizers, and genetically engineered crops allow us to do an end-run on soil. We can use them to grow crops in even the worst soil, at least for three to four years.

After that? They just move to a new field. That's not sustainable, though. We're already using about 40% of the Earth's surface for agriculture. We can't keep moving fields forever. We're simply eroding away soil faster than it's produced.

This isn't a situation where there's going to be a simple technological solution, in large part due to the fact that this is a technological problem. Instead, we need to concentrate on careful husbandry of the land, especially encouraging small farms that use sound long-term strategies.

Thankfully, this is starting to happen, but it's got a long, long way to go. Every single civilization that's neglected its dirt has suffered for it. We've neglected ours for far too long.

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Quotable

Dear Yard Ramp Guy: Onward, reverse-alphabetically. In the meantime, you B most excellent.

“Years later, people look back upon their darkest day and say—as Churchill said of London's war years—‘This was our finest hour.' In a tough spot right now? You may be on the very edge of winning.”

— Guy Lynch