The effects of landcover percentage on runoff and sediment loss in forest road cutslopes

Nowadays, the soil erosion and its associated impacts, is one of the most important environmental problems. The forest road system is a primary area of concern related to runoff and sediment production by removing of tree cover and forest floor cover. However, there is a lack of information documenting the effectiveness of different levels of land cover in reducing sediment loads from back slope of forest road systems. The purpose of this study was the better understanding of vegetation role in runoff and soil loss control in forest roads using rainfall simulator at Azadshahr Kohmian. Therefore, four levels of landcover including 0-20%, 20-40%, 40-60% and > 60%, were used to assess forest road cutslopes in control runoff and sediment by rainfall similator at an intensity of 80 mm h-1 for 30 min. The results indicated that, the first and four classes had maximum and minimum amount of runoff and sediment yield, respectively. The amount of and less effect on with the rates of in control runoff and sediment in cut slopes of forest road by using rainfall simulation at an intensity of 80 mm h - 1 for 30 min. The results showed that different landcover classes resulted in runoff volume and sediment yield ranging from 4.37 lit to 28.35 lit and 6.29 gr to 28.35 gr, respectively. The lowest sediment yield rate and runoff volume were found on the fourth class with 6.29 gr and 4.37 lit, respectively. Moreover, runoff initiation threshold were shown to be a bivariate function of land cover percentage. Runoff initiation threshold was increased from 29 s to 53 s from first class to fourth class, respectively. The results indicated that sediment rates and runoff volumes were significantly influenced by landcover percentage.