An Assessment of the Land Degradation Potential Using the TOPSIS Method (Case Study: Rangelands Overlooking the City of Eshtehard, the Province of Alborz)

Land degradation in different climates drastically disturbs natural ecosystems and reduces the biological production potential of the resources. To investigate the role of geological criteria on land degradation in rangelands surrounding Eshtehard, the map of units was prepared by overlaying and crossing maps of slope classes, land uses, and geological formations using the ArcGIS 10.3 software. Three indices of erodibility, salinity and permeability for each unit were considered and classified. The weights of criteria and consistency ratios were calculated by the AHP method. The TOPSIS method was used to prioritize the alternatives. The weighted normalized values, Euclidean distances, and the relative closeness to the ideal solution were calculated and top priority was given to the land degradation potential (DP) of the units. The results indicated that the relative closeness to the ideal solution obtained from the AHP-TOPSIS technique ranged from 0.002 to 0.991. Accordingly, the study area contains four categories of potential or severity of land degradation, namely: 20872.709 ha (37.97%) of the area with low DP, 1470.297 ha (2.67%) of the area with moderate DP, 1844.861 ha (3.36%) of the area with high DP, and 30788.02 ha (56.00%) of the area with high DP.