Keyline Design 101: Farmers learn water management in field from Mark Shepard
By Paul Durrenberger, Draco Hill
On a hillside of stubble from recently harvested oats, 40 people crowded around a 1960s Oliver diesel tractor in the heat of the August sun on Grant Schultz’s VersaLand Farm near Iowa City, Iowa. The tractor with tandem moldboard plows was supposed to carve a swale to show us how to put in practice lessons we’d learned that morning from Mark Shepard, author of the book Restoration Agriculture. Mark was here at Grant’s invitation to teach a workshop on the methods he has developed for restoring vitality to played-out farms and income to the people who work them. But, the tandem moldboard plows couldn’t get deep enough into the dry, clay-like soil.
After 150 years of commercial farming, the last half of which have been devoted to “conventional” corn/soybean farming with heavy inputs of fertilizers, fuel, and agricultural chemicals, Iowa’s farmland has come to resemble a weed-strewn parking lot when it is hot and dry, and muddy floodwaters when it rains. Grant had brought Mark to the heart of conventional agriculture to explain revolutionary methods of farming.
“First take care of the blue. Then the green. Then the black,” is one of Mark’s slogans. He means first manage the water, then the plants, and the inevitable consequence will be the black soil and black ink in the account books, he explained. We were all there to learn about this system of water management which he adapted from the Australian P.A. Yeomans, whose 1950s books described his system for managing water as it flows over landforms.
My wife and I were keen to learn how to manage water better on our farm. When Suzan and I first moved to our new house at Draco Hill in eastern Iowa, we put in a system of rain barrels and re-directed downspouts to the barrels to store rainwater. Our five barrels amounted to 275 gallons of storage. The first thunderstorm blew out the whole system and left the truncated downspouts spewing water that we had to deflect from the foundation. Like the driving rain that blasted our rain barrel system, fast-moving sheets of water on the land erode soil and wash it into gullies that eat into bluffs and feed fast-flowing temporary streams in ravines that ultimately run into the Mississippi, giving it its nickname “Big Muddy.” That’s how Iowa’s land has migrated to the mouth of the Mississippi, and how Iowa’s agricultural pollution contributes to the dead zone in the Gulf of Mexico.
If we could slow down those sheets of water and channel them to areas of land that need water, both Yeomans and Mark Shepard reasoned, then we could prevent erosion, store the water, and use it to ameliorate the effects of drought, such as the drought Iowa experienced in the summer of 2012.
Key to this water-saving system is Yeomans’s concept of the “key point.” That is the point in the landscape where fast-moving water slows down and begins to drop its load of sediment. This is usually where the slope changes from convex to concave. If you spread your index and middle fingers to make a “V,” you see the little web of flesh between them at their base. If you now hold your fingers parallel to the ground, you can see the “key point.” Such features in the landscape become the crux of keyline management. The next step is to find the contour line the key point is on. That is what Yeomans called the “Key Line.” It was “Key” because that line became the reference point for the rest of the system to slow down the sheeting water and direct it to small ponds where it could soak into the earth.
I had read Mark’s book on permaculture design with great interest when it came out just before the 2013 MOSES Organic Farming Conference. At the MOSES Conference, I found Mark between workshops and showed him a contour map of Draco Hill. I asked where the key point was. I had been unable to identify this increasingly mysterious point.
“It depends,” he answered enigmatically. Another one of Mark’s memorable slogans is: “It’s not a one-answer planet.” Answers to any question depend on many factors. For instance, land ownership boundaries may not follow keyline principles, so a key point may be on someone else’s land. And, that neighbor may be part of the industrial food complex and not want you digging on his or her fields. In that case, you have to locate another reference point for your system. Or, the key point may be very low in the landscape, as it was at Grant’s VersaLand Farm. You could make a pond there, but, since it’s at the lower elevation of the landscape, the water isn’t useful as it cannot flow anywhere. So a more useful point of reference is higher in the landscape.
The 40 of us who had signed up for Mark’s workshop had heard these explanations in an air-conditioned meeting room and now we were standing on a hillside on Grant’s farm watching the plow move along a curving row of flags that marked a gutter line or swale with a grade of 1%—dropping from its high point at a rate of one foot of elevation per hundred feet of length, the same as a gutter around a roof. The problem was that the soil was too hard for the plow to penetrate well. It would take multiple runs to carve out the 18-inch deep swale and heap up the berm downhill. So Grant brought up a trackhoe and the operator he’d hired for the afternoon. The operator began to deftly excavate the swale, one bucket at a time, and deposit the excavated soil just downhill to make the berm.
While the trackhoe dug, Mark asked Grant about the equipment he’d be using on this field—a tractor with an eight-foot wheel base. “So you drive it down and turn around and come back and that’s sixteen feet right there,” Mark said. “Since we’re going to be using machines, we have to build them into the system. The distance to the next swale has to be multiples of 16 feet, so the tractor can end its run where it started.” Grant thought a moment and said he figured he’d need six passes, so that would make a 48-foot alley between the swales.
“Ok, now add a foot on each side so you don’t run into the swales or berms, and you have 50 feet. The next swale has to be 50 feet downhill, just parallel to this one.” Mark had used a laser level on a tripod to find the points on the 1% grade that marked the swale. You could use an optical level like a transit or even something like an A-frame level to find the points at the same elevation, on the same contour line.
“But look—there’s this little valley coming in right here,” an observer noted. “If the next swale is exactly 50 feet from this one, it won’t be level anymore.”
“Let’s mark it first,” Mark said as he measured out 50 feet of cord and gave an end and flags to two people, asking one to stand in the swale the trackhoe was excavating and the other to align himself at right angles lower down and put a flag in at the indicated 50 feet. “Then we’ll check it with the level. If it’s off, we’ll correct it,” he explained. “A plan can be a problem if you think it’s right. On this planet, you can’t do that. Assume the plan is wrong, and build in feedback so you can make corrections as you go.”
The trackhoe had completed a long sinuous swale on a 1% grade across the hillside. Where following the contour would necessitate sharp turns, that is, where little valleys or depressions or rills intersected the swale, the back hoe operator made small “drive through ponds,” wide spots in the swale that were exactly on contour, where water would settle during a heavy rain, and where a tractor could drive across when it was dry. So the swale began to resemble a python that had swallowed several mice—or cats.
“So,” Mark recapitulated, “The first step is to look at the contour map and find the key points and alternate key points to build the rest of the system around. You have to walk the land to check for yourself things like erosion features and so on, so you can lay out the swales at a 1% grade. Then do parallel lines, but check them with a level and correct them when necessary. Then you’ll have a system of swales and ponds to interrupt the sheets of water and take them where you want the water.”
“It looks like the grade is running uphill,” one of the group said.
“That’s an optical illusion. You have to trust your instruments because your eyes can trick you that way,” Mark said. “Trust your instruments. Once you have the swales, ponds, and berms, then you can install the polyculture in the alleys between the swales. Don’t spend money. The quickest way into debt is to start spending money. The quickest way into the black is to avoid that. Set up the system and let it take care of itself. First comes the water, the blue. Then come the plants, the green. And from that comes the soil and your income, the black. Blue, green, black.
“I don’t need to tell you about peak oil, or about how this system,” he indicated the neighboring fields of row upon row of corn and soybeans, “is all out of balance and is not sustainable. Now it’s up to you. Grab a shovel. Plant a tree. Get started. We can save this planet.”
The 40 of us gathered on that hill under the Iowa sun agreed he had it right and thanked him for helping us understand the mysteries of keyline management and how to manage water on our own places.
Paul Durrenberger and his wife, Suzan, live on Draco Hill in Iowa where they are engaged in ecological restoration, permaculture, and organic gardening. See their website at www.dracohill.org.
January | February 2014