SOIL-EROSION ASSESSMENT BY MEANS OF LANDSAT-TM AND ANCILLARY DIGITAL DATA IN RELATION TO WATER-QUALITY

This study uses the well-known Universal Soil Loss Equation (USLE) to assess the long-term soil erosion in a small catchment area. With a mo notemporal land-use classification the C- factor is determined. Land S -factors were extracted from a digital elevation model. Soil studies i n the field provided the K-factor. The factors P and R were set consta nt. All these USLE-factors were used in a GIS to calculate the soil er osion rates. Values greater than 1 t/ha.a are considered to have negat ive impact on water quality since with sediments also nutrients flow i nto the river. Therefore areas with high soil erosion rates are due to soil protection measures. For instance these are very necessary in vi neyards. On the one hand the compiled database allows to determine soi l erosion rates per pixel. On the other hand with this database variou s simulation studies with different land cover types or practice metho ds can be performed to evaluate changes in land management.