An Assessment of Watershed Management Activities on the Soil Erosion Potential Using the Physical LANDPLANER Model in the Treated and Control Sub-catchment of the Goorband in Sistan and Baluchestan

The aim of this study was to analyze the effectiveness of watershed management activities in a representative  sub-catchment (treated) and its comparison with a control on, and to identify the erosion sensitive areas in these sub-catchments areas of ​​58 hectares (control) and 83 hectares (treated) the using UAV photogrammetry. Based on a curve number and four other basic maps (elevation, slope, drainage direction, and accumulation density), three daily precipitation scenarios of 20, 40, and 60 mm were considered to model the LANDPLANER with two indices of Erosion Index and Topographic Threshold. The results were evaluated using the boxplot methods, foufold plot, and the area under the receiver operating characteristic curve. The Erosion index (IE) in the LANDPLANER model, considering the maximum daily precipitation of 60 mm, was 0.54821 for the control sub-catchment which was more than that of the treated one (0.15593). The modeling based on the topographic Threshold also showed that the numerical changes of the index between 0-2 in the trated sub-catchment were less than that of the control area(0-3). Therefore, it can be said that due to the appropriate protective operations that had taken place on the treated sub-catchment, this area is in a better condition than the control one, as the volume of soil erosion was less than that of the control sub-catchment. It is informative to know that all of the three precipitation scenarios predict less soil erosion in the treated sub-catchment. Therefore, simulation based on the rainfall and curve number scenarios with LANDPLANER physical model is recommended to evalute the effect of watershed management activities on the paired sub- catchments that are degraded due to soil erosion.