Assessment of Desertification using the MEDALUS model (Case study: the lands of west Ahvaz)

According to the concept of desertification, which is land degradation in dry areas, the semi-arid, and dry sub-humid due to many factors such as climate change and human activities, this phenomenon has long been known as a serious problem in terms of economic, social, and environmental in many countries. In this study, by using a MEDALUS model the severity of land desertification in the western regions of Ahvaz was evaluated. Climate, vegetation, soil, and land use data are used as effective criteria in determining the severity of desertification. According to the MEDALUS model, each criterion entered the GIS environment as an information layer and after the data is processed, these criteria are weighted. By combining these criteria in raster formats, using geometric averaging, the Environmentally Sensitive Areas Index (ESAI) of the area is obtained. The results show that based on the MEDALUS model the area of the study contains four divisions; (C1) low, (C2) moderate, (C3) high, and (C4) very high critical. The results also showed that 11% of the area was in a low critical class, 30% in the moderate, 25% in high, and 29% of the very high critical class. A climate criterion with the index value of 2.6 has the greatest impact, which is due to strong winds and increasing number of storms and dusty days. Land use criterion with the index value of 1.5 has the minimal impact, which is due to inappropriate land use and implementation of desertification projects in the region.