How to Prevent Earth Erosion

In his short book titled "A Short History of Progress," Canadian author Ronald Wright details how soil loss has directly led to the demise of different societies and civilizations throughout history. With the advent of our industrial civilization, today, we are losing an estimated 24 billion tons of fertile topsoil each year. Industrial agricultural practices are to blame for much of this loss of topsoil. But, the roughly 40 million acres of lawns across the US also contribute to a sizeable amount of erosion.

A typical building site is leveled by bulldozers, compacted by trucks and other construction equipment, and then seeded with an inexpensive type of grass. This site will most likely experience severe erosion as soon as the first rainstorm comes along. But there is a solution for homeowners. Simple erosion control systems can be designed and put in place to help maintain (and even increase) the fertile soil layer essential to our long-term well-being.

Topsoil Acts as a Carbon Sink

Recent studies have shown that a healthy, ecologically intact topsoil layer acts as a carbon sink. Soil carbon storage can capture large amounts of excess carbon dioxide in our atmosphere and help fight against global climate change.

Erosion control is so crucial that the US Green Building's LEED rating system has established it as a prerequisite for all new construction projects: "Use tiers, erosion blankets, compost blankets, filter socks, berms, or comparable measures to stabilize soils in any area with a slope of 15% (6.6:1) or more that is disturbed during construction."

Rain Gardens

Rain gardens are simple pits dug in strategic areas of a yard where rainwater tends to accumulate. For homes in sloped areas, a rain garden can be constructed at a low point in the property where water tends to accumulate. Even in small yards, a rain garden can be placed near the downspout from your roof so that instead of flowing over your lawn and into the sewer system (along with a good bit of your topsoil), your water will infiltrate into the ground. These small pits are usually filled with gravel and topsoil and then top-dressed with finished compost. Water-loving plants such as switchgrass, calla lilies, New England aster, or scarlet bee balm (to name just a few options) can then be planted in the rain garden. These flowers will give you a beautiful flower garden that simultaneously stops erosion, reduces your stormwater runoff, and infiltrates water into your soil.

Bio-swales

Bio-swales are an excellent option for yards with little to no slope. They are small ditches dug on contour (or level), spaced evenly across your yard. These ditches can then be filled with gravel, sand, or compost. During a heavy rainstorm, these ditches will collect the rainwater that is running off your yard. By slowing, spreading, and sinking the water during heavy rains, bio-swales radically reduce topsoil erosion.

Bio-swales can also be incorporated into innovative gardening and landscaping strategy. By densely planting edible shrubs, trees, or flowers on the downside of the bio-swales, these plants will benefit from the extra moisture and the accumulated fertility of collected topsoil. Dense hedges of plants grown parallel to the bio-swales will further reduce erosion. They will also offer you a potential food source and create a habitat for birds and other wildlife.

Stepped Terraces

For homeowners wanting to take on more of a challenge, stepped terraces are another erosion control system that has been used for thousands of years. From Machu Picchu in Peru to China's rice fields, agricultural communities have long relied on terraces to stop erosion. You will probably want to use heavy machinery if you are planning to terrace a large yard. Small terracing projects can be done with nothing more than a garden hoe and some decorative rock.

Ensure you follow the land's contours and create your terraces following them so that the accumulated water won't run off into the storm sewer. Terraced garden beds make for beautiful, unique, and ecologically beneficial landscaping options around the home.

Commercial Erosion Control Systems

Homes that have suffered from severe erosion problems or those located on steep slopes might need to hire experienced landscaping companies to implement more aggressive erosion control systems. These can include:

Gabions Baskets and Retaining Walls

These are rock, brick, or reinforced cinder block walls built as protective barriers on the bottom parts of slopes to hold soil in place. Gabion baskets are cages, boxes, or cylinders filled with concrete, rocks, or sometimes sand. Both gabions and retaining walls need to be anchored into place to resist the force of gravity and stop the erosion. A gabion or retaining wall might also be a great strategy to protect your home's foundation in areas where erosion could threaten your home.

Erosion Blankets

Erosion control blankets are an excellent option for soils that have been disturbed or recently planted, such as the case of new homes. These blankets are manufactured from biodegradable materials such as straw wood or coconut. They are placed on top of barren soil in sloped areas to protect from wind and water erosion. Erosion control blankets are also a great option to protect new seedlings or recently planted landscaping features.

While erosion might not seem like a problem that directly affects us as homeowners, topsoil plays several essential ecological functions. The simple strategies outlined above allow all homeowners to protect and conserve the topsoil where they can.

Article by:

Tobias Roberts

Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.