Assessment of Sediment and the Environmental Factors Affecting the Erosion Using MPSIAC in GIS (Case Study: SoleghanWatershed,Qom Province)

Study area is located at southwestern of Qom، which its area is 16079 ha and minimum and maximum of height in this basin is 1005 and 2500m، respectively. In this study، in addition to design the respective maps and use of M-PSIAC to identifying the sediment، primary and secondary environmental factors that affecting the erosion was measured. Estimation of watershed sediment using M-PSIAC was 19/85 ton/ha/year. Reviewing the weighted average value of 9 factors، indicates that in study area، MV–int (8. 9%)، S1- 2- int (9. 8%)، S1- int (11. 4%)، S2- 1 –int (9. 1%)، S2- int (11. 8%) and in S- int (10. 3%) and S1- 1 1 (12. 4%)، S1- 1 – int (7. 4%)، S1- 2-1 (12. 5%)، S1-2 2 (10. 5%) and S2 -1 -1 (10. 1%)، S2- 1 -2 (9. 6%) and then S2 – 2 (8. 4%) sub- basins، presence of river erosion، geology، topography، vegetation and current state of erosion are contributed، respectively.