Erosion

Included in the 1997 NRI database are data addressing many aspects of land use and the condition of the resources of the Nation. Since the NRCS began inventories in 1934, erosion rates and controls have been a primary concern.

Erosion Types

Erosion is the wearing away of the surface of the earth by the forces of wind, water and gravity. It is a naturally occurring process, which has the potential to be accelerated by the activities of humans, such as tillage, mining, timber harvest, and over grazing.

Erosion is divided into two main types: wind and water.

Water

Water erosion occurs as sheet, rill, and gully erosion. - Sheet erosion is the removal of soil without the development of conspicuous water channels. - Rill erosion occurs as the removal of soil through the cutting of numerous small but conspicuous water channels or tiny rivulets. - Gully erosion is the removal of soil through the formation of relatively large channels or gullies cut into the soil by concentrated runoff.

The NRI estimates sheet and rill erosion together using the Universal Soil Loss Equation (USLE). Classic and ephemeral gully erosion and stream bank erosion are not included in NRI erosion estimates, but may cause significant soil loss in some areas. Water erosion accounts for only a minor portion of Colorado's total erosion. This is due to the semi-arid climate of Colorado along with the high percent of the precipitation being snowfall reducing the amount of energy to displace soil particles.

Wind

The majority of erosion in Colorado is in the form of wind erosion taking place primarily in the plains region of the eastern half of the state. This is also where the majority of dry-land agriculture occurs. The fields are highly susceptible to the strong winds in the spring and fall when ground cover has the potential to be the least without proper conservation measures.

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