Review of Soil Erosion Assessment using RUSLE Model and GIS

Soil erosion is one of the world environmental problems the world is facing in the 21 st century affecting human society and is listed amongst the top environmental issues facing the world including increasing human population, water shortages, loss of biodiversity, energy and human diseases. An estimated 10 million hectares of agricultural lands are degraded and turned into un-farmable areas due to soil erosion thus resulting in reduced food production for the 3.7 billion malnourished people as reported by World Health Organization. Estimation of soil erosion loss and evaluation of soil erosion risk has become an urgent task by many nations before implementing soil conservation practices. There is now a large published literature on the application of the Revised Universal Soil Loss Equation known as the RUSLE model in combination with GIS technology for predicting soil loss and erosion risks in different regions.  This review paper assesses the current literature on the combined application of RUSLE and GIS, examining new developments in deriving the five RUSLE components. The literature review shows that using the traditional RUSLE model in mapping out soil erosion in large watersheds poses challenges. The combined effect of RUSLE and GIS provides a useful and efficient tool for predicting long-term soil erosion potential and assessing soil erosion impacts. However, there is a need to further investigate better ways of deriving the conservation and management factor (P) in the RUSLE for better on future studies. Data source and quality is also another key issue in GIS application, thus great care must be given in checking and pre-processing GIS data, including conversion to different formats, geo-referencing, data interpolation and registration. Finally, validation of the soil erosion loss using reference data is also a valuable input towards improving the quality and correctness of the results. Keywords : Soil erosion, RUSLE, watershed, GIS