Evaluation of SIVAND basin erosion by RUSLE model during 1998 to 2009

The presence of human in nature and his willing or unwilling activities have culminated in a series of destruction and balance clash in the nature. Today، the increase of population and high demand for agriculture production has resulted in the destruction of plant coverage on the land particularly forests and grassland by human and increase the erosion. In this paper، via using world soil erosion equation and applying TM satellites images (1998) and ETM (2009) the erosion of Sivand River was highlighted for two periods of 1998 and 2009. For the extraction and processing of satellite images the ERDAS was used and for mapping and its related analysis the Arc GIS and SPSS software were used. The results showed that the erosion in 1998 was 406172389 tons and in 2009 was 416364377 tons which shows 1. 87 tons increase in each hectare. The main cause of erosion changes during the course of study was the decrease of plant coverage which resulted from population increase as well as the interference in nature and immethodical grazing in grassland areas which decreased the soil coverage and weakened the soil against rainfall and other factors.