مقالههای Gholamreza Zehtabian
توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقالههای نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده میشوند.
اطلاعات انتشار: Pollution، دوم،شماره۲، ۲۰۱۶، سال ۰
تعداد صفحات: ۱۵
Groundwater aquifers are an important source of water supply for agriculture, industry and drinking. The present study investigates the changes in the quality of groundwater using geostatistical methods in the Ravar plain during a 10–year period. In this study, after selecting the appropriate spatial interpolation method to draw water quality parameters such as TDS, SAR and EC, zoning maps of Ravar plain were provided for three periods of time: the first period (2002–2005), an intermediate period (2006–2009) and the final period (2010–2012) in two seasons using ArcGIS 10.1. For this purpose, data were evaluated in GS+ 5.1 software, after calculation, the best model with the lowest estimated error was selected for zoning water quality parameters. Because of the lowest estimation error, Kriging, Gaussian and Spherical variogram models were selected as appropriate interpolation method for zoning the quality parameters. The results of the spatial analysis of TDS showed that TDS have been increased in the study area. Due to the amount of dissolved solids, EC amount was highly variable. According to the Wilcox classification, at the end of the period, water quality of agricultural was inappropriate in most of the area which represents the increase of electrical conductivity during the period.
۲Hazard Assessment of Desertification as a Result of Soil and Water Recourse Degradation in Kashan Region, Iran
اطلاعات انتشار: Desert، نوزدهم،شماره۱، ۲۰۱۴، سال ۰
تعداد صفحات: ۱۱
Desertification in arid, semi–arid and dry sub–humid regions is a global environmental problem. Considering the increasing importance of desertification and its complexity, the necessity of giving attention to desertification criteria and indices is essential. Models and methods such as MEDALUS, UNEP–FAO, and others have been proposed on local and national scales. In this research, IMDPA was selected from among different existing methods, and desertification intensity was evaluated on the basis of two criteria, soil and water, and 13 indices: soil depth, electrical conductivity of soil, texture, gravel percentage, drainage, sodium absorption ratio, type of geologic formation, slope, groundwater table fluctuation, electrical conductivity of water, color concentration, water crisis index, and water shortage for livestock and wildlife. Each criterion was assessed based on the selected indices which resulted in the qualitative mapping of each criterion based on the geometric average of the indices. Finally, a sensitive map of the region was extracted using the geometric average of all criteria. Thematic databases with a 1:50000 scale resolution were integrated and elaborated in a GIS based on ILWIS and arcGIS. Analysis of desertification criteria in the Kashan region showed that, among the studied criteria, water criterion is a major problem in the study area. It has a geometric average of 3.59 which shows very high class, while soil criterion with a weighted average of 2.12 stands in the medium class of desertification. The results also showed that groundwater decrease and water crisis index with a quantitative value of 3.72 classified in a very high class of degradation and depth with quantitative value of 1.20 classified in a low class of desertification were the most and least effective factors, respectively, among the studied indices on land degradation.
اطلاعات انتشار: Desert، نوزدهم،شماره۲، ۲۰۱۴، سال ۰
تعداد صفحات: ۱۳
The assessment of de–desertification alternatives can be effective in controlling the reclamation of disturbed land and avoiding destruction of areas at risk. Until now, there has been no method to consider different criteria and alternatives, or to present the optimum alternatives based on systematic structures and experts’ perspectives. Desertification is a complex process resulting from various factors, including anthropogenic activities; the selection of optimum alternatives is a very difficult task. This paper attempts to represent the optimum alternatives based on the Multiple Attribute Decision–Making Model (MADM). For this purpose, the initial priorities for alternatives were determined by Expert Choice (EC) software via Elimination and Choice Translating Reality (known as ELECTRE). Then, the final priorities for alternatives were assessed using the Analytical Hierarchy Process (AHP). This model was tested in the Khezr Abad region, Yazd Province, to evaluate the determination of optimum alternatives. The results indicated that prevention of unsuitable land use changes, vegetation cover development and reclamation, and changes in groundwater harvesting, with weight averages of 22.9, 21.8 and 19.1 %, respectively, are the most important desertification alternatives in the study area.
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