Line is Drawn Between Natural and Human Accelerated Erosion

Steamboat Springs, CO—The causes of erosion and increased sedimentation in our waters are varied and complex. The results of erosion are just as broad, ranging from amazing natural beauty such as the Grand Canyon to disastrous flooding and the destruction of wildlife habitats.

While it is not always possible or essential to protect land from the effects of natural erosion, there are many measures that can be taken to prevent erosion caused by humans. But first a distinction between natural erosion and human accelerated erosion must be made.

The International Erosion Control Association (IECA) has issued a position statement defining “human accelerated” and “natural” erosion. The statement draws a line between problems triggered by natural events such as hurricanes which are often intensified by human causes such as vegetation removal and land development.

The IECA is a source for information and strategies to combat human accelerated erosion and to control natural erosion which threatens human developed property and activities.

To read more about the distinction between human accelerated erosion and natural erosion in the following position statement.

For more information about controlling human accelerated erosion visit www.ieca.org.

IECA Position Statement: The Distinction Between Natural Erosion and Human Accelerated Erosion

Author: Tom Williams
Reviewers: Erosion and Sediment Control Technology Section
Adopted: April 2006
Expires: April 2011

The International Erosion Control Association (IECA) is dedicated to providing the ways and means to address human accelerated erosion and in controlling natural erosion when it threatens human activities or projects. Consequently, definitions of “human accelerated” and “natural” erosion are necessary.

Human accelerated erosion is defined as any erosion increase over historical levels from an area following any human activity or event measurable by: increased sediment load in run-off, down gradient wind or water cutting or deposition, reduced air quality or visibility due to wind erosion, rill or gully erosion due to water flow, or any other means of measurement. Human accelerated wind or water erosion may be caused by such events and activities as: vegetation removal for land development, over grazing, changes in water regimes, fire caused by humans, agriculture, timber harvesting, road construction, mining, or other human activity. Mass wasting, such as slumping, landslides or rock falls are not included in the definition of human accelerated erosion, as they are or can be a result of human accelerated erosion, but are not considered a cause of erosion themselves.

Natural erosion is defined as any wind or water erosion caused by natural, or non-human controlled, events or activities. Natural erosion may be caused by catastrophic events such as tornadoes, hurricanes, volcanoes, tidal waves, earthquakes, or other natural event. Natural erosion may also be caused by more common natural events such as non-human altered stream flow, stream meandering, wave action on shorelines, sheet flow from rainstorms, or snowmelt. Natural erosion may also be caused by animal activities such as grazing, trail use or heard movements, so long as they are wild animals and not subject to human control, with the acknowledgement that this limits natural animal caused erosion to very few instances.

It is acknowledged that natural erosion is part of the cause of such natural wonders as the Grand Canyon in the United States, Victoria Falls in Zimbabwe and Zambia, the Harbor at Rio De Janeiro in Brazil and many other natural wonders around the world. IECA is in no way an advocate of changing or influencing natural erosion of this scale or beneficial significance. However, where natural erosion threatens human developed property, activities or projects, such as homes, parks or businesses constructed along shorelines, streambanks or on hillsides, IECA is an advocate for erosion and sediment controls to protect the developed land from natural as well as human accelerated erosion.