The effectiveness of watershed management operations in reducing erosion and sedimentation in the Nakarood watershed in Mazandaran province

Soil erosion reduces the fertility of upstream lands and damages downstream lands through sedimentation. A field survey was conducted to investigate the performance of each structure in the Nakarood watershed to evaluate the effect of watershed operations on erosion and sedimentation. The watershed operations carried out include coastal wall, spillway, and stone-mortar and biological operations. In addition, taking into account the factors affecting erosion and sedimentation (terrain structure, specific peak discharge and uncovered lands), the EPM model, GIS, and SPSS software were used for the analysis. The results showed that the three factors of land construction (r=0.8), flood (r=0.47) and land use (r=037) had the greatest impact on erosion and sedimentation in the region. Also, the factor of land construction and then flood have more effectiveness. According to the correlation results, these three factors had a significant correlation with erosion, so that the land construction of the area has a significant correlation with erosion (r=0.8) and is determined to be the main factor. Also, rainfed lands under biological treatment have been more effective in reducing erosion and sedimentation in the region. Also, the comparison between before and after watershed operations for different uses showed that erosion and sedimentation decreased more in rainfed agriculture. In general, land use changes significantly affect soil erosion. Therefore, it is very important to take necessary measures to reduce erosion and sedimentation and to preserve the soil of the region. In addition, biological and structural programs and remedial structural operations should be implemented in the watershed to manage water and soil resources and increase the effectiveness of watershed operations in reducing erosion and sedimentation and increasing the land cover layer.