Soil Conservation & Erosion Control :: Dryland Solutions, Inc.

Soil erosion is a problem virtually everywhere. Soil loss may be the greatest threat to the long term survival of humanity. 90% of the land-based diversity of biological species is in the soil. Without the complex biological process sustained by living soils, life above ground simply would not exist. In drylands, soil loss is especially severe and detrimental. Soil is the moisture storing medium that separates ecologically rich drylands from true biological deserts. Soil loss leads to moisture loss, which leads to vegetation loss, and in turn - increasing rates of soil erosion. This process is a downward spiral known as desertification and it is occurring all over the world right now. Desiccated soils support very little life above and below the surface. Healthy soils retain moisture and nutrients and provide everything needed for plants and animals to flourish. Ultimately, living soils support our every need and are our best hope for sequestering carbon on a global scale. In drylands, soil conservation is synonymous with moisture conservation.

Dryland Solutions uses a variety of erosion control methods based on passive water harvesting principles (learn more about our erosion control methods). We believe that it is not enough to simply control erosion. Soil conservation must first seek to address the root causes of erosion, such as poor land management practices, improper road drainage and sparse vegetative ground cover. Top soil and organic matter are eroded from the surface first, and followed predictably by deeper layers of soil. Artificially concentrated surface runoff, regardless of the cause, greatly accelerates soil loss. For this reason, we focus on maintaining dispersed flow everywhere possible. This allows moisture to infiltrate readily and supports dense vegetation. Where dispersed flow cannot be maintained, it is necessary to dissipate the energy of concentrated flow to allow sediment deposition and moisture infiltration. Erosion in each of these cases is caused by a different surface flow condition and our methods are designed to deal with the dynamics of each situation, as well as the transitional phases between them.

This wide transitional headcut formed as sheet flow was concentrated at the top of a gully network at Arroyo San Pablo, NM.
The headcut was laid back with hand tools, seeded and covered with hand-placed rock in a collaborative project with the Cuba YCC, Rio Puerco Management Committee and Dryland Solutions.
Two years later, the headcut is stabilized and supporting a dense and diverse community of native plants.

Transitional headcuts, like this one, are caused by sheet flow that is concentrated at the top of an eroding gully network. In this case, it is necessary to create a stable transition from sheet flow into the newly formed gully channel. This Rock Mulch Rundown stabilizes that transition and provides a protective environment for perennial grasses to grow. Previously, there had been little or no plant growth.

One Rock Dams placed between the meander bends at the riffles/crossovers of an eroded gully, Santa Fe Botanical Garden, NM.
Early plant recruitment in the rock mulch created by a One Rock Dam, Santa Fe Botanical Garden, NM.
Dense plant cover one year after construction, Santa Fe Botanical Garden, NM.

Once a deep gully channel has formed, it is very difficult to fill it in or get water out of it. To stabilize gully erosion, we use low grade control structures known as One Rock Dams to slow runoff, encourage deposition and recruit plants in the channel bottom. One Rock Dams are placed at meander crossovers/riffles to maintain or enhance the existing meander pattern and sediment transport process in the channel.

Actively eroding headcuts dehydrate the landscape.
In-channel headcut (2ft tall) before treatment, Ojo Encino Chapter of the Navajo Nation, NM.
Zuni Bowl constructed by workshop participants with locally available sandstone.

Headcuts found in established channels should be treated differently than transitional headcuts found at the top of gully networks. An in-channel headcut is an abrupt drop off in the channel bottom with an associated scour pool at its base. The people of Zuni Pueblo and Bill Zeedyk developed a headcut control structure known as a Zuni Bowl to stabilize in-channel headcuts. The shape of the Zuni Bowl is specifically designed to prevent erosion at the pour-over and at the scour pool, while dissipating the energy of the falling water and retaining soil moisture.

Gabion baskets, like this one, are often erroneously used for erosion control. They frequently fail because they do not readily conform to natural shapes, and they do not actively recruit plant growth. Eagle Creek Watershed, AZ.
A multi-step Zuni Bowl was constructed from locally available rock to repair this gabion during an Erosion Control Workshop at the Double Circle Ranch.
After one year and several significant flood events, the Zuni Bowl has stabilized the 4ft headcut, encouraged the deposition of sediment and recruited dense vegetation.

Soil Conservation & Erosion Control

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