TAYYEBEH MESBAHZADEH; farshad soleimani sardou
Abstract
Due to incorrect policies in the water resources sector and excessive withdrawal of groundwater resources, water quality in most plains of the country has decreased. Therefore, the quality of water for drinking and agriculture is important in qualitative terms.With this aim in this study, the desertification ...
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Due to incorrect policies in the water resources sector and excessive withdrawal of groundwater resources, water quality in most plains of the country has decreased. Therefore, the quality of water for drinking and agriculture is important in qualitative terms.With this aim in this study, the desertification changes in Khash plain were studied using two criteria of groundwater and vegetation. Shooler and Wilcox diagrams were drawn up for AquaChem software for the years of 2001, 2008 and 2015. Also, spatial variations were made on Arctic plain surface using Arc GIS software and vegetation changes trend were also done using MOD13A2 sensor images and remote sensing techniques. The results showed that the number of wells that have an unpredictable TDS in the years 2008 and 2015 compared to 2001 have been increased by comparing the Schuler diagram. However, the level of lands with good drinking status decreased during the years 1387 and 1394 compared to 1380 and was increased by the level of acceptable drinking water. According to Wilcox's diagram, the result is that most wells are salty to very salty and their use is harmful to agriculture or requires measures. The results of the vegetation change trend also indicated that the trend is to reduce vegetation and the average level of the NDVI index decreases with the passage of time.
Nooshin Shakerian; Gholamreza Zehtabian; Mohammad Ali Zareh Chahooki; Hassan Khosravi
Abstract
Nowadays, land degradation and desertification are serious and complex problems that have turned into a worldwide crisis in the world. Using evaluative systems to study degradation and adopting an appropriate strategy to deal with this phenomenon is necessary and important. The first step in the ...
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Nowadays, land degradation and desertification are serious and complex problems that have turned into a worldwide crisis in the world. Using evaluative systems to study degradation and adopting an appropriate strategy to deal with this phenomenon is necessary and important. The first step in the study of land degradation and desertification is determining criteria and indicators that affect upon this process. Therefore, in this study the importance and priority of a considerable number of criteria and indices that influence upon land degradation and desertification were examined. Accordingly, 8 criteria and 49 indicators were chosen based on questionnaires and expert panel and they were evaluated based on eight metrics. We weighted suitable criteria for evaluation indicators with the help of Shannon entropy method, and then by using the TOPSIS method (one of Multiple Attribute Decision Making Methods) we determined the most effective indicators on land degradation and desertification for management and dealing with this phenomenon. The results show that among the evaluation criteria and indices that should be considered for a benchmark or index, a scale, has the highest weight and importance, and being sensitive to change, has the minimum weight and importance.The results of the prioritization and ranking criteria and indicators based on TOPSIS model indicates that the severity of exploitation of water resources in the factor of water with the 0.79 efficiency, has the most effect and the use of facilities and personal management in the management factor with the 0.11 efficiency has less effect in land degradation and desertification.
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.
zahra giveiiashraf; Mohammad Ali Hakimzade; Mohammad Zare; Zohre Ebrahimi Khusfii; Kazem Dashtakian
Abstract
Desertification relates to the both the process and end state of drylands degradation. Salinization and alkalinization are two indicators of soil degradation in arid and semi-arid regions. The main objectives of this research is monitoring of soil salinity using high spectral and spatial resolution of ...
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Desertification relates to the both the process and end state of drylands degradation. Salinization and alkalinization are two indicators of soil degradation in arid and semi-arid regions. The main objectives of this research is monitoring of soil salinity using high spectral and spatial resolution of remote sensing to assess desertification in the Marvast plain, Yazd province. Two images of Terra satellite, ASTER synchronous to 2003 and 2010 are used. After preprocessing and analyzing of the images, relationship between parameters of soil salinity (i.e. SAR and EC) and spectral reflections were determined and, both two satellite images were classified using maximum likelihood method. Then, the surface area of each class and the amount of its changes were calculated. Results showed that during the period of 7 years (2003-2010), area of non-saline lands has decreased while, the area of saline land has increased, which leads to the salinization of agricultural lands, reduction of its yield and also extent of desertification in this region. Accuracy of EC map classification for 2003 and 2010 images are 87.5% and, 82.5%, respectively. Kappa coefficients for both images are 0.83 and 0.76. Accuracy of SAR map classification for 2003 and 2010images are 87.5% and 87.5%, respectively. Kappa coefficients for these two images are 0.81 and 0.77, respectively. Generally, it can be conclude that using of remote sensing data, especially ASTER images has high efficiency for change detection analysis in soil salinity and natural resources management.
shima nikoo; Hossein Azarnivand; Gholam Reza Zehtabiyan; Hasan Ahmadi; Mohammad Ali Zare Chahouki
Abstract
Combating desertification which is a serious threat for the environment and human welfare requires understanding complex issues of this phenomenon using evaluation, awareness of severity of it's processes and determination of it's factors. So here, after recognizing the characteristics of the region ...
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Combating desertification which is a serious threat for the environment and human welfare requires understanding complex issues of this phenomenon using evaluation, awareness of severity of it's processes and determination of it's factors. So here, after recognizing the characteristics of the region showing existence desertification, we assess its current status with emphasis on climate, water, geology-geomorphology, soil and wind erosion as the most criteria of desertification. According to more consensus on regional model or flexible model to modify, Iranian Model for Desertification Potential Assessment (IMDPA) ,which is calibrated to use in arid area of Iran, was chosen. At first the rainfall seasonality indicator was added to the model as a special climate character. Then primary assessment of desertification was done. At last according to the result of primary assessment, the area environmental conditions and revealed issues during assessment the model was modified, final assessment and mapping of desertification were done. At last according to the result of primary assessment, the area environmental conditions and revealed issues during assessment the model was modified, final assessment and mapping of desertification were done. Based on the results desertification intensity in 33/94% and 66/06% of the area are severe and moderate respectively. Also the major factors affecting desertification across Damghan region are climate, salinization of water and soil resources, improper land use, over exploitation of underground water, over grazing and improper irrigation method.
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.
E. S. Shokoohi; Gh. R. Zehtabian; A. Tavili
Abstract
More than 80% of Iran’s area has arid and semi arid climate. Therefore, Iran is exposed to desertification process. Practical activities in controlling desertification must be based on current desertification situation and its severity. Based on this theory, evaluating desertification rate indices ...
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More than 80% of Iran’s area has arid and semi arid climate. Therefore, Iran is exposed to desertification process. Practical activities in controlling desertification must be based on current desertification situation and its severity. Based on this theory, evaluating desertification rate indices in Khezrabad region was done based on IMDPA model. In this research two factors with 10 indices were investigated. Each of the investigated indices was analyzed and scored based on work units. Data layers of each index were made by Arc GIS software. By compiling data layers and calculating geometric mean of indices, desertification rate map of the region was then prepared. According to the selected indices, final desertification map shows the mean rate of desertification. Soil index by 2.21 scoring value was classified in median class while water index by 1.46 scoring value was classified in poor class. Soil depth had the biggest influence while SAR and Cl of water had the least influence on desertification. Based on the assessments, geometrical mean of desertification rate quantity value for the entire region was 1.76, thus the entire region was classified in median class.
s.h Parvari Asl1; ahmad Pahlavanravi; ali reza Moghaddam Nia
Volume 63, Issue 2 , September 2010, , Pages 149-16
Abstract
Desertification is the consequence of series of processes in which climate change and human activities are more important factors than others. Arid and semi-arid areas have occupied most parts of Iran. Sistan region is one of arid areas of Iran where wind erosion is an important factor of land degradation ...
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Desertification is the consequence of series of processes in which climate change and human activities are more important factors than others. Arid and semi-arid areas have occupied most parts of Iran. Sistan region is one of arid areas of Iran where wind erosion is an important factor of land degradation and soil deterioration. For classification of desertification intensity, several methods have been proposed so far. ESAs Model is on of the best and recent methodologies introduced by the European Commission in 1999 and evaluated by most of European as well as Middle Eastern countries. ESAs has more advantageous than other methods because of its accuracy, particular weighing of layers, use of geographical information systems in overlaying of maps, use of geometric mean over arithmetic one or sum in computing indices and final desertification map. The method was chosen to monitor desertification in the study area. The factors which affect on desertification were evaluated based on the related tables. According to the conditions of the study area, it was found that four factors including vegetation cover, soil, climate and land use management are the most important desertification factors. The results showed that climate play vital role in land degradation and desertification. Based on the results of it is found that the study area has critical conditions. It includes high critical (C3), moderate critical (C2) and low critical (C1) classes of desertification which cover 68%, less than 1% and 31% of the region, respectively.
s.m Hoseini; M.R Ekhtesasi; A.R Shahriyari; H Shafiei
Volume 63, Issue 2 , September 2010, , Pages 165-18
Abstract
Sistan plain is affected by desertification and this phenomenon has serious impacts on roads and socio- economic activities of local people of this region. The main purpose of this study is estimating the current and potential desertification intensity of Niatak region of Sistan based on MICD method. ...
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Sistan plain is affected by desertification and this phenomenon has serious impacts on roads and socio- economic activities of local people of this region. The main purpose of this study is estimating the current and potential desertification intensity of Niatak region of Sistan based on MICD method. That, through it the working units of this region were prepared as the base map for evaluating to consider the factors and indices by geomorphology method. Also, in order to prepare the desertification intensity condition for both current and potential situations of this region, the desertification intensity of various applications was determined and relative plans to current and potential desertification of each land use were prepared after evaluating wind erosion indices and accumulating their scores for each working unit based on reference tables. The results showed that in this region the desertification potential consists of medium (III), intensive (IV) and very intensive (V) classes, while current desertification condition includes low (II), medium (III) and intensive (IV) classes of desertification intensity, respectively. These variations were resulted by wind erosion control activities over recent years.
