Watersheds of the World - Area Affected by Water Erosion
| Analytical Overview |
| The basic units of the Global Assessment of Soil Degradation (GLASOD) database are based on physical geographic criteria, but attributes assigned to each unit are based on expert opinion, not empirical data. For this analysis, polygons identified as having a moderate to strong degree of water erosion as the primary cause of soil degradation were selected. The polygons were converted to a 1 square kilometer grid using the factor field, which indicates the proportion of the polygon affected. This method assumes that the erosion is evenly distributed across each polygon. The sum of grid cell values within each basin was calculated, representing the total area in square kilometers affected by erosion. Data are presented as a percentage of the total basin where erosion is occurring. |
Map Projection
Robinson
Map Description
This map shows watershed basins which are experiencing moderate to extreme levels of water-related soil erosion (loss of top soil and terrain deformation). The water erosion indicator is based on the Global Assessment of Soil Degradation (GLASOD), developed by the International Soil Reference and Information Centre (ISRIC) for the United Nations Environment Programme (UNEP). The basins with the highest levels of water erosion are found mainly in China, Southeast Asia, India, and Madagascar. Other basins, such as the Orange and Volta basins in Africa, the Danube, Dnieper, and the Guadalquivir basins in Europe, and the Balsas and Uruguay basins in Central and South America, have more than 15 percent of their land area exposed to moderate to extreme water erosion.
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Citation:
Revenga, C., S. Murray, J. Abramovitz, and A. Hammond, 1998. Watersheds of the World: Ecological Value and Vulnerability. Washington, DC: World Resources Institute.
Sources:
- UNEP - ISRIC (International Soil Reference and Information Centre). 1990, Global Assessment of Soil Degradation (GLASOD). Wageningen, Netherlands: