Determination of Erosion and Land Degradation Intensity in Taham Chai Basin Using the P.S.I.A.C Model and GIS

One of the biggest problems concerning natural resources is the issue of soil erosion. With loss of soil, the most important source of human production is eliminated, a disaster which is impossible to compensate for. In order to accurately identify the factors of soil degradation, exact basic information is needed. Today the existence of instrumentation systems and different models have enabled human being to store and, if necessary, recover basic information. In this paper, using the P.S.I.A.C model and capabilities of the GIS system, the lands belonging to Taham Chay basin are evaluated for erosion and sedimentation. For this purpose, the combination of PSIAC and GIS models can estimate the erosion severity and the amount of sediment produced in basins. Considering that topographic maps, slopes, directions and geology are all instrumental in determination of homogeneous units, these data were entered into the system's environment (GIS) as information layers, and after processing and organizing them, the classification and scoring of each of the effective factors in the intensity of erosion and sedimentation were carried out according to the P.S.I.A.C model. Finally, by summing up the scores of each of these layers, the final score is extracted, and based on this the intensity of erosion and sedimentation of the studied area is determined. According to the results of this research and previous experiments, this method can be used in areas where the erosion and sedimentation intensities are “low” to “very low”. Furthermore, in comparison to the amount of sediment obtained through the method in question with the actual amount measured in the hydrometric station set in the outlet of the basin, it was observed that the estimated result is in acceptable consistency with the measured values.