The evaluation of effective factors on marls erosion by rainfall simulator in Hamedan

The marl soil types are very sensitive to erosion and are deposited into reservoirs ofdams and areas of flood spreading in form of considerable sediment annually. Thisprocess increases the expenses of filtration of drinkable water and pre-filtration of waterof artificial recharge severely. So the investigation of marl soil types from differentaspects is very important for experts and researchers. In this research, it was tried torecognize the effective variables on erosion rate of marls in Hamedan province. 49samples of 41 spots in 3 marl areas were taken to determine the physical and chemicalproperties. The characteristics of place of sampling like; slope, geographical situationand privilege of 7 parameters for surface factor of soil were noted. Also, the test ofsimulated rain was done by the Kamphorst΄s rainfall simulator apparatus in the 41above spots and 41 samples of runoff were taken and the amount of soil lost weremeasured and calculated by simple method in the laboratory. The amounts of 23physical and 15 chemical variables were determined. Then, all data were evaluated byKolmogorov-Smirnov test and the abnormal data were normalized by logarithm andwere evaluated by correlation, bi-variate and multivariate regression tests. The resultsshowed that only 9 variables have significant and linear relation with soil loss, whereplastic index, clay percent and clay ratio are the most important variables for evaluationof marl soil loss at marls of investigated areas respectively.