Journal of Spatial Analysis

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Every year, natural hazards happen severely around the world. Iran is included in the first 10 countries in the world susceptible to natural hazards, and has experienced 30 hazards out of total 35 hitherto. In this connection, moving sands, as a natural hazard, creates changes to ecological conditions which cause a rupture in the lives of people. The aforementioned hazards leave adverse effects on human habitations and impose wide environmental and socio-economic damages upon societies. Moreover, the sand mass covers arable lands and residential areas, generates air pollution, brings in destruction of topsoil, harms animals, and brings about many losses. This eases desertification and causes damages. Therefore, taking areas subject to moving sand into consideration is very significant in rural planning. Hirmand township in north of Sistan and Balouchestan province is an area open to moving sand onrush. Unfortunately, due to Sistan drought and Hamoon international wetland dryness as a result of the dominant120-day winds in the area, moving sands have come to affect rural settlements. This has put the villagers of Hirmand township to so much trouble. Hence, an investigation and analysis of rural settlements vulnerability to moving sand damages in the villages of Hirmand township is of great significance as a step toward better control of the problem.

      The present study is a descriptive-analytic survey containing documentary sources, field studies, as well as village and household questionnaires.  The statistical population consists 303 villages in Hirmand township, from which a total of 56 were selected as the sample of the study based on advice given by experts at Housing Foundation of Islamic Revolution, rural administrators and local council members. Analytic hierarchy process (AHP), statistical analyses, spatial analyses, and the software Expert Choice, SPSS, and ArcGIS were used in data analysis. This study, hence, attempts to identify vulnerable habitations and categorize them by employing 54 indexes and assessing and putting them together in different levels.

      According to the findings of this study, from the total villages subject to moving sand problem, 55.35 % are found with low or very low vulnerability and 30.38 % are placed in high or very high vulnerability ranges. The investigation of distribution of the villages under study given the vulnerability intensity to moving sand storm revealed that the villages of low or very low vulnerability are situated in the central and western parts of the area under study. These villages enjoy low vulnerability due to water resources, Tamarix hispida trees planted by state-run entities in the moving sand paths, and being away from dry bed of Hamoun Wetlands. On the other hand, the villages of high and very high vulnerability are placed mostly in the northern part of the area under study and adjacent to Hamoun Wetlands.   

There are several factors playing key roles in vulnerability of rural areas including environmental elements such as stopping of incoming water flow into Hamoun Wetlands, winds of 120 days, wide geomorphological functions of moving sands, and high reduction in the density of vegetation and trees around and in the villages due to drought. In addition to the above factors, inconsistency of physical context of villages with the movement direction of moving sands has caused accumulation of sands in villages which is effective in vulnerability intensification of many rural areas.

    Ruin of houses and cut of communicative roads by moving sands cause disruption in normal lives within the aforementioned villages. In addition to taking damages by moving sands into consideration, the evident role of state services is very significant in decreasing of the damages in all parts of Hirmand. In this connection, belt-like flood preventives built around the international Hamoun Wetlands has made moving sands accumulated behind them and this has decreased intensification of the damages and probable threats from sand onrush to the lower latitude regions.    

    Accordingly, the results of affecting level comparison of different factors in appearance or intensification of the moving sand’s effects in the villages under study revealed that the effects of weather factors and water restrictions sprung from hydrological droughts in which the incoming flow of Hirmand River into the area under study is cut or decreased remarkably, along with summer winds (winds of 120-days) and severe winter winds are more clear and stronger in intensification of soil erosion and formation of moving sands than other factors.   

    On the other hand, the results of impressionability level comparison of different contextual-spatial factors in the villages under study demonstrated that sand affects arable lands and water supply networks more than other factors.

     However, given that reduction or stop of incoming water flow of Hirmand River into Sistan region over the recent years has caused successive droughts, some factors like drying of Hamoun Wetlands, intensification of environmental dryness, reduction of vegetation and increase of soil erosion along with Sistan’s winds of 120-days have paved the way for increasing of dust storms and movement of sands toward the villages of the region.

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Introduction: Wetland ecosystems, especially marine coastal wetlands of the most important and also the most vulnerable are the world's environmental resources. Which has always been sensitive to the fragility of coastal areas, high population density and intensive human activities are faced with the threat of destruction. Based on this, monitoring the trend of the changes in wetlands and their surrounding lands can be effective in the management of these valuable ecosystems. Investigating the environmental risk is a suitable instrument for evaluating and ensuring understanding of the relationships between stressor factors and environmental effects especially in wetland ecosystems. In general, application of methods of evaluating environmental risk is one of the important tools in studying environmental management along with identifying and mitigating potential environmental damaging factors in wetland regions in order to achieve sustainable development. Today, multi-criteria decision-making methods are employed in evaluating the risk in many studies.This study is based on multi-criteria decision-making methods to identify and analyze the risks threatening Tyab- Minab International wetland located in Hormozgan province was conducted.
Materials and methods: Based on the methodology to identify and prioritize risks Delphi, AHP and TOPSIS techniques were used to determine the risk priority number. In the first phase of this study, to identify and screen the main criteria of project selection, Delphi method was used. In this study, the panel of interest was determined based on a combination of experts with different expertise and out of a sample of 20 individuals, in which experts with various expertise gave a score from 1 to 5 (Likert scale) to each criterion. In this way, 32 criteria were identified as the most important and considerable risk for Minab Wetland and further proceeded to the second phase for prioritization and analysis. In this stage, multi-criteria decision-making methods were used, in which hierarchical analysis process was employed for prioritizing the criteria using Expert Choice 11 software. The indices of risk evaluation including the impact intensity, incidence probability, and the sensitivity of the receptive environment in environmental risk evaluation of wetlands do not have an equal value and significance. For this purpose, to weight the factors effective in estimating risk level and for prioritization of risk options, the technique for order of preference by similarly to ideal solution (TOPSIS) and Excel software were benefited from for calculations. The spectrum of scoring to each of the indices of incidence probability, impact intensity, and the sensitivity of the receiving environment was chosen from very low (1) to very high (9) based on hour spectrum. Following investigation of the types and frequency of indices along with the method of score determination of these indices, three indices of risk intensity (C1), risk incidence probability (C2), and the sensitivity of the receiving environment (C3) were chosen for risk ranking using TOPSIS model. Next, after determination of risk priority number using TOPSIS, the risk levels were calculated and evaluated using normal distribution method for each risk. To determine the degree of risk-taking, risks are organized in a descending order, where the elements of the number of the class and the length of the class are determined based on Relations 1 and 2 (n is the number of risks). Next, the risks are categorized based on these classes. Considering the concept of ALARP, the risks under investigation are divided into high risks, medium risks, and low risks. In this study, considering the number and length of classes, the studied risks were categorized in six levels (critical, intolerable, considerable, medium, tolerable, and trivial risks).
 

(2)

(1)

the number of classes=1+3.3 log (n)
the length of the classes= the greatest risk value - the smallest risk value/the number of classes
Results and discussion: In the first step, the final indices of the wetland's environmental risk were identified and the development of hierarchical tree and classification of the risks threatening wetlands along with their incidence probability in two groups of natural and environmental criteria was performed. Eventually, the final weight of criteria resulting from paired comparisons was obtained in Expert Choice 11 to achieve the score of incidence probability of each risk. Based on the results, among the natural, social, economic, physiochemical, biological, and cultural criteria, drought and climate change, increase urban and rural development, Smugling of fuel, oil pollution, reduce the density of vegetation, indiscriminate exploitation of groundwater were of high priority. The results obtained from ranking the the risks threatening Minab Wetland using TOPSIS suggest that oil pollution, dam construction upstream, persistent drought and climate change, and sometimes alcohol and fuel smuggling and illegal overfishing the priorities are first to fifth. Also Results showed that the respectively based on (Cj+) oil pollution (0/9109), dam construction (0/8121), the drought and climate changes (0/8063) and the smuggling of fuel (0/7520) are in Unbearable level.
Overall, the results indicated that same as this research, wetland ecosystems are subject to many threatening factors, resulting in ecological imbalance and abnormal appearance of the wetland, putting the wetland entity into danger of extinction in terms of fauna and flora.
Conclusion: Nowadays, for assessment of environmental risk, various methods are used, each of which has positive and negative points given the studied environment and the conditions governing it. Therefore, one cannot reject or approve one method with total confidence. By employing novel methods in risk evaluation, the intensity of risk incidences and, in turn, the damages and losses incurred to the environment can be prevented or at least mitigated. Further, it is also possible to move in line with proper and optimal management of environmental resources, especially wetlands and with sustainable development. Undoubtedly, understanding and recognition of the factors threatening wetlands, according to the importance and the impact of them, Prevent and cope with the threats and accurate project preparation and implementation of wetland conservation plans and environmental management.

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Assessment of the Probable Impacts of Land Use Changes on Water Quality in Shadeghan
Wetland Using Remot Senseing Data
 
In this research, the evaluation of possible effects of land use change on water quality in Shadegan wetland has been provided with the help of remote sensing data. The purpose of this research was to evaluate and compare user variations in 2000 and 2015 using Landsat satellite imagery (with ETM and OLI sensors) from the study area and processing them in the ERDAS software environment using the unstructured classification method during a period of 15 years old has been investigated. To determine the cause of the changes occurring in the wetland, the water quality of the wetland was evaluated through the help of modeling. Vegetation in the wetland has been rising rapidly, indicating water pollution, an increase in the nutritional status and the early disappearance of this international wetland. With the help of this article, it can be admitted that the development of agricultural lands around the shadegan wetland from 2000 to 2015had caused an increase in pollution in the region, according to available agricultural wastement containing  quantities of herbicides and pesticides which has led to an increase in the growth of algae in the wetland, which has led to an increase in temperature and eventually the death of wetlands and aquatic animals so after selecting images and assign them in 5 classes, the change wetland  maps were obtained during a 15 year various sources were used to determine the best regression model for determining water quality changes in the following, the images were placed in the models and their mean and standard deviation were obtained. The result of the research showed that the Landsat sensor shows the water quality well and can be used to determine the changes. The development of agricultural lands leads to an increase in the eutrophication phenomenon in the wetland and, in the end, reduces the quality of water indicators. In the end, causes quality loss of water.
Key words: Assessment, Land Use Changes, Water Quality, Shadeghan Wetland, Remot Senseing.
 

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Potential dangers of drought in Shadegan wetland and Identify areas affected by dust from it
 
Introduction
Shadegan wetland is located at the end of Jarahi watershed. This wetland is one of the most important international wetlands registered in the Ramsar Convention, which is currently undergoing ecological changes and is still on the red list of the Montero Ramsar list. This wetland is extremely important due to its high biodiversity and various functions such as flood control, air conditioning and soil erosion control, habitat of various plants and animals and providing livelihood for a part of human societies. One of the most important functions of the wetland, according to the findings of the present study, is the important role of Shadegan wetland in preventing the production and control of fine dust. There are 143 wetlands in Iran, of which 25 are registered in the Ramsar Convention. Shadegan wetland is one of the wetlands of Ramsar Convention, which in the last decade, a large area of ​​it has become dry and has become a center of dust. In this research, it is important to know that in case of drying of Shadegan wetland, which areas in which seasons will be more affected by dust due to atmospheric currents.
Data and methodology
In this study, the boundary of the wetland was determined based on the highest water advance line during a 30-year statistical period (1988-2017). According to satellite images, the border of the wetland has been determined to be about 164,000 hectares based on the rainiest year and month. Wetland area changes were used to monitor the water level of Shadegan Wetland through Landsat TM, ETM + and OLI satellite data from 1998 to 2017 in the period of June. Three stages of preprocessing, processing and post-processing were performed on the images and supervised classification by support vector machine (SVM) method was used and the images were classified into three classes of water, vegetation and without cover or soil. On the other hand, the classification accuracy for the images was calculated using two indicators, overall accuracy and kappa. To calculate the dry area of ​​the lagoon, floor changes without cover were calculated. The most important cities around Shadegan wetland, which in case of wetland drought may be most affected by wetland dust due to proximity and proximity, and have socio-economic importance and the center of the province and port status, were identified. In this study, the cities of Ahvaz, Abadan and Mahshahr were identified and studied as areas affected by wetland dust during drought. In order to study the role of drying of Shadegan wetland in the dust of the surrounding areas, seasonal and annual dust mites were prepared and drawn. Data on the direction and speed of hourly winds along with the dust were used. Then, using WR-PLOT software, in addition to the annual long-term total rainfall, the seasonal distribution of the direction and speed of events was extracted and the rainfall related to each season was plotted and analyzed, and areas affected by drought in different seasons of the year. Wetlands with greater impact were identified.
 
Result
The trend of 30-year changes in the soil cover of Shadegan wetland is increasing in total, so that according to the freshwater area of the wetland, which was obtained in this study 164 thousand hectares, 22960 square kilometers has been added to the dry area of the wetland during these 30 years. The largest soil area of the wetland in 1994 was about 87.4% of the total area of the wetland. The lowest soil area of the wetland in 1998 was about 19%. Sugarcane projects have entered the wetland from the north of Shadegan Zahab Wetland since 2002, but due to widespread drought, it has not been able to increase vegetation and reduce the soil area of the wetland.
During the long-term statistical period, spring is the predominant period of pollination in Ahvaz western synoptic station and secondarily in the northwest. The southeast direction is of third importance, but nevertheless, the dryness of the north and northeast parts of the wetland can affect the south and southeast of Ahvaz in this season in Abadan synoptic station. Drought on the west side of the wetland is not a threat to the city of Abadan. In Mahshahr synoptic station, the predominant direction of long-term seasonal rainfall is northwest. In case of drought, Shadegan wetland will be affected from the northwest. During the long-term statistical period, the summer season was dominated by dust and affected in three stations, such as the spring season, with the difference that in this season, dust is more abundant. During the long-term statistical period, autumn is the predominant direction for flowering and is affected in three stations such as spring and summer, but in this season, the southeast and south directions are more intense and frequent than spring and summer.
During the long-term statistical period, winter is the predominant period of pollination in Ahvaz synoptic station, west and secondarily, northwest. The southeast and south directions are of third importance, but in this season, the southeast and south directions are more intense and frequent than other seasons. In this season, due to the expansion of the westerly wind to the lower offerings, unstable atmospheric systems enter Khuzestan from the south and southeast and bring dust with them from areas such as western and southern Iraq and northern Saudi Arabia, and to the southeast. Northwest and passing through the dry parts of the lagoon and the active dust center of the southeast of Ahvaz, the metropolis of Ahvaz will face problems caused by dust in this season. Due to the cold weather and the inversion phenomenon, the dust of this season, which is associated with wetland and inland resources, has a greater impact on the field of view and causes great damage to the equipment and infrastructure facilities by subsiding on the city of Ahvaz.
Conclusion
Drying of wetlands due to various climatic or human factors can lead to increased dust activities. When a wetland dries out, the salts that settle in it become sources of dust. Wetland fine-grained sediments with air velocity less than the erosion threshold due to small diameter and large volume enter the air streams and are dispersed in the air. Active dust centers in the southern half of Khuzestan province have the largest area in the whole country. Shadegan wetland is bounded on the north by the dust center of the south and southeast of Ahvaz with an area of ​​185043.3 hectares and on the west by the center of the south of Horalazim and north of Khorramshahr with an area of ​​258916.4 hectares and on the east by the dust center of Mahshahr - Omidieh Hindijan with an area of ​​254654.4. Shadegan wetland joins the southeastern center of Ahvaz in case of drought from the north and northeast, as if parts of it, known as Hor Mansoureh, have become part of the southeastern center of Ahvaz in the last decade due to several droughts. Is. From the west, parts of it are connected to the dust center north of Khorramshahr and join it if the drought continues. It is connected to Mahshahr-Omidieh and Hindijan centers from the east. In recent years, parts of the wetland and dust centers have overlapped. If the wetland continues and dries, for natural and managerial reasons, more parts of the wetland will dry up and become dust centers and affect important population, political and port cities of Khuzestan Data and will face irreparable social and economic losses.
 
Keywords: Dust center, dust, wind direction and speed, Shadegan wetland, Right of water
 

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Vulnerability assessment of Miangaran wetland ecosystem

To support the proper management of ecosystems, vulnerability analysis of ecosystems is very important. Vulnerability analysis of ecosystems provides information about weaknesses and capacity of the studied ecosystem for recovery after damage. Considering the degradation status of Miangaran wetland, vulnerability evaluation of this wetland is one of the most important management methods in the region. For this purpose, in this study, after identifying and evaluating the threatening factors of Miangaran wetland, these factors were scored using evaluation matrices. Then, the interaction between these values ​​and threatening factors was examined and the vulnerability of wetland values ​​was obtained by multiplying the scores of all studied factors. Finally, management solutions were presented to deal with the most important threatening factors. According to the results, the most vulnerability is to the hydrological and ecological values ​​of the wetland. The highest effects of threats on the ecological value are also on the birds of Miangaran wetland. The results of the evaluation of Miangaran Wetland show that this wetland has a high potential for ecosystem functions of the wetland. These functions have been neglected in the planning and managing of wetlands at the local, regional and national levels. As a result, ecosystem-based management is suggested as the best management approach. The management in these areas should take action to prevent the vulnerability of Miangaran wetland. Also, the vulnerability evaluation method used in this study can provide a good understanding of the relationship between wetland functions and the resulting services for the management of the ecosystem of Miangaran Wetland.
Key words: Miangaran wetland, ecosystem management, vulnerability assessment

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