Reyhaneh Masoudi; Gholamreza Zehtabian; Hassan Ahmadi; Shahram Khalighi sigarudi
Abstract
Desertification is a major problem in many countries. International efforts have been considered to combat and prevent this phenomenon. The most important cases of these measures are the United Nations Convention to Combat Desertification. In this study, IMDPA model and GIS were used to assess desertification ...
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Desertification is a major problem in many countries. International efforts have been considered to combat and prevent this phenomenon. The most important cases of these measures are the United Nations Convention to Combat Desertification. In this study, IMDPA model and GIS were used to assess desertification phenomena in Kashan Plain. Some indices of Climate and water criteria were selected to consider for each condition of the region. Final desertification intensity was calculated based on geometric average of the selected criteria and their indices. The numerical value was classified in 5 classes including non-significant, low, medium, severe and very severe and desertification intensity map was drawn using GIS in the studied period. According to the results, among the studied indices, the groundwater level depletion, EC and Transu aridity index with 3/82, 3/04 and 3/01 numerical values are the most effective factors. The threshold of ground water level, EC and Transu aridity index were determined respectively: more than50 cm/year, 2250-5000((μmohs)⁄(cm)) and 0/05-0/2. Also, the case study has classified in medium class of desertification with DS=2/4. Regarding the determined thresholds were specified the sensitive areas, and the required equipment are proposed to install on these areas for observing the thresholds.
Afshin Jahanshahi; Alireza Moghaddamnia; Hasan Khosravi
Abstract
To assessment and preparation of desertification mapping, much research has been conducted ever within and outside the country that has led to numerous regional models. To provide a regional model and quantitative assessment of current state of desertification, ShahrBabak plain with an area of 4112 square ...
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To assessment and preparation of desertification mapping, much research has been conducted ever within and outside the country that has led to numerous regional models. To provide a regional model and quantitative assessment of current state of desertification, ShahrBabak plain with an area of 4112 square kilometers (Km2) located in the Northwest of Kerman province were considered. In this study, to assess the severity of desertification using thirteen indices that five of them based on groundwater and include: electrical conductivity (EC), sodium absorption ratio (SAR), chloride (Cl), drop of groundwater and water table depth and three of them based on climate data and included: annual rainfall, Transeau drought index, drought index and also three of them based on vegetation and included: Conditions, exploitation and restoration of vegetation, water erosion and irrigation methods in format of desertification Iranian model IMDPA to investigation and determine the class of desertification intensity were done in each of work units. The final score of each of work units and then total area were determined using Geometric average from any of the mentioned indices. Finally the current status of desertification intensity classes were estimated in low, medium, high and very high classes. The results indicated that in the regional proposed model, the study area with respect to intensity of desertification is placed in about 61351 ha (14.92 %) in low class and about 138575 ha (33.7%) in medium class, about 117685 ha (28.62 %) in high class and about 93589 ha (22.76 %) in very high class. Also the weight average of quantitative value estimated 2.06 in total area that it indicated the medium desertification class in the total area.
Elham alsadat Abrisham; Sadat Feiznia
Abstract
The Derakhte Senged area is located in south of Neishaboor town at Khorasan Razavi province. In this research, desertification intensity of Derakht senged area was evaluated using IMDPA, one of the newest method to Assess desertification potential in arid and semi arid regions of Iran. To evaluate desertification ...
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The Derakhte Senged area is located in south of Neishaboor town at Khorasan Razavi province. In this research, desertification intensity of Derakht senged area was evaluated using IMDPA, one of the newest method to Assess desertification potential in arid and semi arid regions of Iran. To evaluate desertification intensity, based on the primary research in this area, 4 criteria were selected including vegetation cover, soil, climate, geology and geomorphology. Each criterion was assessed based on the selected indices which result in qualitative mapping of each criterion cased on geometric mean of the indices. Then, sensitive map of region was extracted using geometric mean of all criteria. By laminate of thematic databases layers and using geometric mean of main criteria intensity map was obtained. The results showed that 0.37 % of study area categorized in low class, 80% was medium and 19.63% involved high class of desertification. Analysis of desertification criteria in this region showed that among study criteria, vegetation cover criteria is a major problem with a geometric average of 3.05 which shows high class, while geology and geomorphology with a weighted average of 1.8, has moderate effect in desertification. Also, climate and soil criteria with a geometric average of 2.04 and 2.21 show medium class desertification.
Tayyebeh Mresbahzadeh; Hasan Ahmadi; GHolamreza Zehtabian; Fereydun Sarmadian; Firoozeh Moghiminejad
Abstract
Desertification is specific phenomenon of arid, semi-arid, dry sub humid regions. This phenomenon has a high rate in developing countries such as Iran. The main objective of this research was calibration of IMDPA model in Abuzeidabad (Kashan) region with emphasis on land criteria. IMDPA model, introduced ...
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Desertification is specific phenomenon of arid, semi-arid, dry sub humid regions. This phenomenon has a high rate in developing countries such as Iran. The main objective of this research was calibration of IMDPA model in Abuzeidabad (Kashan) region with emphasis on land criteria. IMDPA model, introduced by Iranian researchers to assess desertification intensity in Iran. Before application, the criteria and indices applied in model were re-defined For this study. Regarding to region conditions three criteria were defined as key criteria for desertification which were: Geology-geomorphology, soil and wind erosion criteria. Then each criterion was assessed based on selected criteria, which resulted in qualitative mapping of each criterion based on selected criteria. Finally, by mean of all the indices and criteria desertification mapping was provided and these results obtained. Regarding the studied criteria, Geology– Geomorphology benchmark has the highest effect on desertification. Among the total studying are (16161 hectars), the medium class is about (4792 hectars), and the high class is about (11369 hectars). Among indicators, slop index with 3.9 and lithology sensitivity to erosion and wind erosion with the value of 3.5 and 3.4 are the main indexes of increase in desertification intensity in the study area. According to map of desertification statue 70.3% of study area have a high intensity and 29.7% have a medium intensity.
