|Change in Average Annual Soil Erosion by Water|
|Source: Natural Resources Conservation Service|
This shaded polygon map shows the change in the average annual rate of soil erosion by water in tons per acre per year on cropland and Conservation Reserve Program (CRP) land between 1982 and 1997. The Universal Soil Loss Equation (USLE) is used to determine annual erosion rates. Data are aggregated by 8-digit hydrologic unit areas. Areas where cropland and CRP land occupy less than 5% of the total area are hatched. Areas with 95% or more Federal area are shaded gray. There was a net decrease of 1.4 tons per acre per year between 1982 and 1997.
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 higher erosion rates in some areas. Note that no CRP land was recorded in 1982, since the program did not begin until the mid-1980s. Data are not shown where cropland and CRP are less than 5% of the total area. Data are not collected on Federal land. Data are not available for Alaska or the Pacific Basin. Data for Puerto Rico and the U.S. Virgin Islands is shown by 6-digit hydrologic unit. For Further Information: