The early and widely accepted soil erosion models consist of relatively simple responses
function that was calibrated to fit limited numbers of statistical observations (eg. USLE,
SLEMA). The current trend is towards replacing these by far more elaborated process based
models (Sonneveld, et.al, 1999). Among these models, WEPP (water prediction program) of
the USDA, EPIC (the erosion productivity impact calculator), CREAMS (chemical, runoff and
erosion from agricultural management systems), and EUROSEM (European soil erosion
model) can be listed as an example. However, Sonneveld et.al (1999) urges that in case of
Ethiopia and many other developing countries the application of these process-based models is
not practically applicable due to their large data requirement. In contradiction with it, the issue
and the impact of soil erosion in Ethiopia is still extremely severe, an assessment on the basic
soil erosion model that best fit with the available resource is imperative.