Effectiveness of Watershed Operations in Controlling Erosion and Sedimentation Using MPSIAC Experimental Model (Case Study: Saqezchi-Chay Watershed, Ardabil Province)

During the recent decades, the loss of water and soil resources in watersheds due to their inappropriate exploitation has become increasingly intense, this issue has reduced the production and useful life of reservoirs and increased the amount of sediment production. Today, with the advancement of technology, examining the impact of projects by measuring the effective parameters and studying how to achieve the goals are part of the basic principles of project evaluation. In this study, according to the implemented mechanical and biological operations, the role of watershed operations in controlling erosion and sedimentation in the Saqezchi-chay watershed of Ardabil province was investigated and compared using the MPSIAC method before and after the operation. In this model, 9 effective factors in erosion have been considered, each of which has a score depending on its intensity and weakness, and finally, taking these scores into account, the sedimentation rate of the area is considered. The results of the research show a relative decrease in erosion and sedimentation in the area of watershed operations and, on the other hand, an increase in erosion and sedimentation in other areas without watershed operations, which indicates the positive effect of watershed operations in increasing vegetation and soil protection. Also, the implemented watershed management measures, in addition to increasing the concentration time in the watershed and groundwater feeding, have played an important role in preventing the reduction of the storage volume of the Saqezachi dam. The results indicate the effectiveness of watershed projects in reducing sedimentation in the study area; In such a way that the amount of erosion in the watershed has changed significantly.