Assessment and mapping of desertification using modified MEDALUS Model (A Case Study of Sistan Region)

Land degradation in arid and semiarid areas as a result of human activities and climatic conditions is called desertification. Today, human societies are encountering the desertification phenomenon as a serious problem which causes various irreparable damages to economic and social sectors. Several models have been developed for evaluation and mapping of desertification. In the present study, the ongoing conditions of desertification in Niatak Region (of Sistan) have been investigated based on wind erosion criterion by using the Modified MEDALUS Model. To do so, first, the maps of work units of the region or homogeneous desert profiles were prepared as the base plan for evaluating and scoring factors and indices under question by the use of geomorphology method. Then based on the work units and field visits of the region, four indices related to the model including data layer of wind erosion model (IRIFR Model), the number of days with dust storm indices (DSI), the percentage of density of living organisms on the soil surface (PC), and the data layer of the soil compression resistance were scored using the base table. And finally by obtaining the engineering means of information value for the four mentioned layers, the desertification severity was determined for each work unit using the table related to the calculation model and the map of present desertification conditions in the region. The obtained results indicated that of the whole studied region(comprising 4819.6 acres), 2651.56 acres (55%) are located in medium desertification intensity class, 1269.48 acres (26.34%) are positioned in severe desertification intensity class, and 898.54 acres (18.64%) are placed in very severe desertification intensity class.