Map Description:
This is a shaded polygon map where soil erosion by water on cropland and
Conservation Reserve Program (CRP) land is displayed in five shaded classes of tons
per acre per year using these ranges: Less than 1, 1 to 3, 3 to 5, 5 to 8, and 8 or more.
The Universal Soil Loss Equation (USLE) is used to determine the values. The shaded
polygons represent 8-digit hydrologic units. Areas where cropland and CRP land occupy
less than 5% of the total area in 1997 are left blank. Areas with 95% or more federal lands
are shaded gray. 40 million acres are eroding at a rate above 5 tons per acre per year due
to water.
Cautions for this Product:
Erosion by water includes sheet and rill erosion and
excludes gully erosion. Since cropland and CRP land may occupy only a small percentage of the total
area of some of the polygons, the map may leave a misleading impression as to the significance of
higher erosion rates in some areas where there is little cropland. Data are not collected on Federal
land. Data are not available for Puerto Rico, Alaska,and the Pacific Basin.
For Further Information:
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