By Mary Ann Lieser
Permaculture and water conservation are inseparable. Permaculture design starts with water —with looking at what happens to the precipitation that falls on a piece of land and at how to shape the land so that each drop of rain can bring as much benefit as possible.
Water stewardship is increasing in importance, a trend certain to accelerate in the future. Droughts are more common, current water supplies are less dependable due to depletion or contamination, rainfall patterns are more variable and weather events more extreme. Unless a landscape has been designed to capture and retain as much water as possible, intense storms usually result in more runoff and the erosion of valuable topsoil, without the full benefit of the precipitation infiltrating the soil.
We face a collective future in which widespread water shortages are likely. And agriculture, which accounts for the single biggest use of water on the globe, is already being affected in many places. The underground supply has been depleted and groundwater recharge is not keeping pace. Too often, stormwater flows to rivers and oceans.
But permaculturists have always regarded water as the precious resource that it is, and they have been developing ways to reduce water loss and maximize retention for decades. Permaculture design is always site specific, so they begin by looking at what you have. How much rainfall does your land receive in an average year? What is the highest point on your property, and what are the existing patterns of water flow? Then it’s possible to look at shaping your land to encourage beneficial water flow patterns.
Typically, only a fraction of the rain that falls on a piece of land reaches the roots of the plants growing there. Permaculture aims to slow it down, spread it out, and sink it more deeply.
The soil itself is the easiest place to store water, and the more organic matter in the soil the better it will soak up moisture. Jason Gerhardt has been a permaculture teacher and designer for over fifteen years, with experience in a variety of settings — from desert to temperate forest and urban to rural. He advises farmers to “think about the landscape in terms of a sponge. What can we do to help the soil absorb and hold onto more moisture?” Higher quality topsoil and the judicious use of mulches and groundcovers (which can act as living sponges) reduce runoff and allow more water to reach deeper layers. And increasing organic matter in the soil sets the stage for a virtuous circle: more moisture in the soil results in healthier plants and more soil microbes and will therefore build additional topsoil more quickly.
Beyond soaking in more moisture wherever it falls, permaculture uses design features to shape the land and direct water flow. Keyline design focuses on the existing flow pattern as a guide to placement of trees, irrigation systems and ponds. Swales are broad, shallow trenches dug along the contours of shallow slopes, and can prevent runoff and gulley formation. A keyline system and swales can channel water away from valleys to achieve better distribution, so that rainfall can soak the soil more evenly.
Rainfall can also be directed into ponds for storage or harvested from rooftops to provide water when needed for irrigation, livestock or other agricultural purposes.
Gerhardt, who serves as director of the Permaculture Institute as well as founder of Real Earth Design in St. Louis, often finds inspiration from traditional land-based cultures. “Indigenous people all over the world have developed methods to absorb and retain rainfall, whether it involves diverting streams, flooding paddies or terracing hillsides.”
Todd McCree’s Great Escape Farm in West Virginia includes a nursery focused on the sale of propagated cuttings of edible plants, from familiar fruits like blackberry and raspberry to more unusual ones like aronia (chokeberry) and pawpaw. McCree uses permaculture principles at every level of his operation, including a collection system that harvests rainwater from a 24 by 51 foot metal roof. Two 1,550 gallon containers provide enough water storage for the farm to space out the area’s 37 inches of annual rainfall to supply mist irrigation when needed.
Edible Acres, a plant nursery in the Finger Lakes region, is also based on permaculture principles and also harvests rainwater for agricultural needs. Sean Dembrosky oversees the nursery and the water harvest, which takes place on a combination of many small roofs, ranging in size from two hundred to eight hundred square feet. The water is stored in a collection of 275 gallon IBC totes and some 55-gallon drums placed strategically under downspouts. What began partly as an experiment to see what could be done in an area that receives 34 inches of rain annually, has convinced Dembrosky that “it is 100 percent possible to run a viable nursery business based on collected rainwater and simple hand dug ponds and holding tanks. No well is necessary for full-on farming.”
Gerhardt advises that those who may not be ready for comprehensive farmscale watershed management might start small, taking just a few steps in the direction of water stewardship. “Once they see the impacts, they often want to do more.” And for those ready to dive into learning how to apply permaculture principles to water management on the land they tend, the single best source is Brad Lancaster, who writes and teaches about permaculture design. Lancaster lives in semi-arid Tucson, which receives a mere twelve inches of precipitation a year, yet he manages to harvest 100,000 gallons of rainwater annually for household and garden use. His website (harvstingrainwater.com) and his books Rainwater Harvesting for Drylands and Beyond, volumes 1 and 2, share what he’s learned in decades of studying and consulting on water harvest in every climate.