Desertification is one of the main environmental and also social and economic problems facing Iran. Seventeen out of 31 Iranian provinces, which are home to approximately 70% of the total population, are affected by desertification. This study aimed to use geographic information system (GIS) and fuzzy logic for mapping environmentally sensitive areas to desertification based on Mediterranean Desertification and Land Use approach in Isfahan province, central Iran. Six desertification indicators including climate, soil, vegetation, soil erosion, groundwater, and management and policy quality were used to determine various types of environmentally sensitive areas to desertification. Seventeen desertification indices affecting the quality of each indicator were spatially mapped and assigned a value between 0 and 1 using a fuzzy logic option of ArcSDM3 software in GIS environment. Results showed that a 21·7% of the study area was classified as critical, 70% as fragile and 5·5% as potential, and 2·9% of the area was not affected by desertification. In the town of Borkhar, 64·2% of the area was classified as critical, followed by the towns of Isfahan and Nayin with 40·2% and 31·8%, respectively. Results at provincial scale indicated that the climate indicator and humidity index with a weighting mean of 0·71 and 0·77 were the most affective factors in the desertification of the study area. The developed model in this study can be used for mapping desertification status in other 16 provinces that contain desert areas. These assessments provide a GIS-based desertification database that Iran as a member of the United Nation Convention to Combat Desertification can use to report the condition of desertification at national scale. Copyright © 2013 John Wiley & Sons, Ltd.

Quantitative Mapping and Assessment of Environmentally Sensitive Areas to Desertification in Central Iran

The Kouh-e Zar mining area with iron oxide-rich types of Cu–Au (IOCG)-type gold mineralization is located in a fractured zone between two main “Darouneh” and “Taknar” faults in 35 km northwest of Torbat-e Heydarieh. In this study, the hydrogeochemistry and water quality of groundwater were examined for irrigation uses. Totally, 11 groundwater samples were collected in semi-arid area surrounding the mine. According to the irrigation water quality indices such as sodium absorption ratio, sodium percentage, residual sodium carbonate, residual sodium bicarbonate, potential salinity, salinity index, salinity hazard, permeability index and magnesium hazard, the water resources were appraised suitable to unsuitable. Na+ was a dominant cation and HCO3− was a dominant anion in the water samples. Fortunately, SO42− content is low (< 250 mg/L) in the water samples because of low-sulfide content mineralization in this mine. Water–rock interaction was defined as the controlling process on groundwater chemistry based on the Gibbs diagram. Calculated saturation indices revealed that the anion and cations in groundwater originated from dissolution of minerals and evaporation process. In the case of dominant Ca2+ and Mg2+, they were originated by dissolution of carbonate minerals such as calcite, dolomite and aragonite. Na+ was likely originated by plagioclase weathering in the brecciated volcanic rocks. Though the sulfidic mineralization is not so high in the Kouh-e Zar area, however, considering the existence of metalogenic mineralization in the Kouh-e Zar area, there is also a risk potential of release of toxic elements into the groundwater on which further deep investigation is ongoing in the area.

Assessment of groundwater suitability for irrigation in a gold mine surrounding area, NE Iran

No method exists to increase the efficiency of controlling projects and reclamation of disturbed lands and avoid investment wasting, considering different criteria and alternatives and presenting optimal alternatives based on systematic and group perspectives in combating desertification. Recent proposed alternatives are usually non-systematic and non-comprehensive according to a scientific view. There is no record of application of systematic models such as multiple attribute decision-making in combating desertification. Therefore, in the present research, a fuzzy analytical hierarchy process (FAHP) method has been used to offer optimal alternatives challenging desertification. In the present study, the opinions of experts about alternatives and criteria have been assessed using the Delphi method and pairwise comparison. Then, the final priorities of the alternatives were obtained by a fuzzy decision matrix and the FAHP model. The model’s ability in offering alternatives to combat desertification was assessed in the Khezr Abad region, Yazd province. Based on the obtained results, the alternative of groundwater harvesting modification with weighted average of 93 % was determined as the optimum alternative in the study area; other alternatives had no effective effect in control of desertification.

Application of fuzzy analytical hierarchy process for assessment of combating-desertification alternatives in central Iran

Spatiotemporal assessment of groundwater quality for irrigation is essential for agricultural management. This study was conducted to quantify the spatiotemporal changes of Kerman groundwater irrigation quality during 1999–2010 using geostatistical analysis combined with a new method established based on regression coefficient (RC). Result showed that among the main soluble ions, Na+ and Cl− had the highest concentrations. Except Ca+2, the average concentration of all other soluble ions and also EC were higher than the maximum permissible levels for drinking, however, Na+, SO
 4
 −2
 and EC showed no limitations for agricultural irrigation. Based on the proposed RC, soluble Na+, Ca+2, Cl−, total cations, total anions and EC have gradually increased over the years. Soluble Cl− with 0.18 meq l−1 y−1 showed averagely the highest value of RC. Also, EC exhibited an increasing trend with an average value of 16.8 µS cm−1 y−1. In contrast, Mg+2, SO
 4
 −2
 and SAR exhibited negative values of RC, while the value for HCO3
 − was zero. Based on nugget-to-sill ratios, the groundwater variables had moderate to strong spatial structure. Finally, the spatiotemporal changes of groundwater salinity (EC) and sodicity (SAR) have been mainly controlled by Na+ and Cl−.

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Spatiotemporal mapping of groundwater quality for irrigation using geostatistical analysis combined with a linear regression method

. Nowadays desertification, as a global problem, affects many countries in the world, especially developing countries like Iran. With respect to increasing importance of desertification and its complexity, the necessity of attention to the optimal combating-desertification alternatives is essential. Selecting appropriate strategies according to all effective criteria to combat the desertification process can be useful in rehabilitating degraded lands and avoiding degradation in vulnerable fields. This study provides systematic and optimal strategies of combating desertification by use of a group decision-making model. To this end, the preferences of indexes were obtained through using the Delphi model, within the framework of multi-attribute decision making (MADM). Then, priorities of strategies were evaluated by using linear assignment (LA) method. According to the results, the strategies to prevent improper change of land use (A18), development and reclamation of plant cover (A23), and control overcharging of groundwater resources (A31) were identified as the most important strategies for combating desertification in this study area. Therefore, it is suggested that the aforementioned ranking results be considered in projects which control and reduce the effects of desertification and rehabilitate degraded lands.

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Zehtabian Gholam Reza

Papers

Modeling of ground water spatial distribution for some chemical properties (case study in garmsar watershed)

Application of analytical hierarchy process (ahp) in assessment of de-desertification alternatives case study: khezrabad region, yazd province

Calibration of medalus model to present regional model for desertification intensity (case study: kashan)

Evaluation of desertification intensity in segzi plain using imdpa model

Application of icd method for determining the severity of desertification in koohdasht watershed