Zahra Abdollahpour; Aliakbar Nazari samani; Mahmoud Arabkhedri
Abstract
Understanding the processes of soil degradation, including erosion, is crucial for its conservation, given the lengthy process of soil formation. Among various forms of soil erosion, the damage caused by mass movement and gully erosion is particularly significant at the watershed scale. This phenomenon ...
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Understanding the processes of soil degradation, including erosion, is crucial for its conservation, given the lengthy process of soil formation. Among various forms of soil erosion, the damage caused by mass movement and gully erosion is particularly significant at the watershed scale. This phenomenon is considered an objective and key criterion for assessing the severity of land degradation. The current research aims to determine the extent of gully erosion across Iran and investigate its relationship with climatic elements (temperature and precipitation) and its impact on erosion and sedimentation at the watershed scale. Initially, a primary database on gully erosion was established through a review of articles, theses, reports, projects, and consultations with specialists, followed by the use of Google Earth and field visits for validation. By integrating the gully erosion layer with provincial boundaries,climate (De-Martonne), and second-order watersheds ,the extent of gully erosion in each of these areas was determined. Finally, the relationship between climatic elements, total erosion and sedimentation, and specific sediment yield with gully erosion at the second-order watershed scale was examined. The results indicate that the total area affected by gully erosion is 3,207,314 hectares.Golestan Province, the semi-humid climate, and the Gorganrud-Qarasu watershed have the highest relative density of gully erosion, with values of 15.3, 2.2, and 20.8, respectively.The relationship between specific sediment yield, total erosion and sedimentation, and the area affected by gully erosion is significant and positive, with an increase of one unit in gully erosion area leading to an increase of 209.81 tons per square kilometer per year in sediment yield.Therefore, to determine the vulnerability degree of second-order watersheds and prioritize regions requiring soil conservation measures, factors such as the status of agricultural land use, presence of dams, road conditions, and elements at risk should be considered, alongside the likelihood of gully erosion occurrence.
Shahbaz Mehrabi; Mohammad Reza Yazdani; Mehdi Ghorbani
Abstract
Prevention is the most appropriate way to deal with natural hazards. And resilience means maintaining the structure and function of the socio-ecological system in the face of unexpected events, one of the important branches of prevention. Chaharmahal va Bakhtiari province, due to its specific geographical ...
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Prevention is the most appropriate way to deal with natural hazards. And resilience means maintaining the structure and function of the socio-ecological system in the face of unexpected events, one of the important branches of prevention. Chaharmahal va Bakhtiari province, due to its specific geographical location, faces numerous environmental hazards annually. Therefore, in this study, the status of resilience in the face of environmental hazards in the governing system of this province was investigated. AHP method was used for this purpose. In the AHP process, based on the pairwise comparison of criteria and sub-criteria, the degree of association between both criteria and sub-criteria is compared and scores between 1-9 are assigned. The research data was analyzed based on Delphi method and hierarchical decision making process. The results showed that according to expert’s evaluation of resilience of socio-ecological systems of Chaharmahal va Bakhtiari province against climate change (4.51), drought (2.09) and soil erosion (2.02) were ranked first to third respectively. Because of this, climate change has attracted the attention of experts who have shifted the rainfall to snow ratio over the past two decades. So that from 70% snow and 30% rain, to 70% rain and 30% snow. However, much of the economic activity and livelihoods in the province depend on snow reserves.
mina pouresmaeel; ali salajegheh; Arash Malekian; amirreza keshtkar
Abstract
The complexity of the urban environment makes it difficult to consider all the vulnerable components of the urban. Hence, decision-making in urban environments is one of the most important issues in modern management. As a result, the purpose of this study is to investigate the urban vulnerability of ...
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The complexity of the urban environment makes it difficult to consider all the vulnerable components of the urban. Hence, decision-making in urban environments is one of the most important issues in modern management. As a result, the purpose of this study is to investigate the urban vulnerability of Azimiyeh in Karaj to flood based on multi-criteria decision-making method. The statistical population includes specialists who had sufficient knowledge and experience in the field of vulnerability management in urban areas. To this research, first, comprehensive knowledge of the factors affecting the urban vulnerability to floods was obtained using library studies, and then, the results of the Delphi technique, , was shown that among the primary indices, a total of 11 effective indicators were selected and a map of each of them was prepared using ArcGIS software. Then, the urban vulnerability to floods was calculated using the TOPSIS method. The study area was divided into 13 sub-areas based on runoff directional pattern and field observations, and then the decision matrix was made according to 13 sub-areas and 11 indicators. The results showed the vulnerability of this region to floods, which among the studied sub-areas, in sub-areas No. 1 and 2 observed the highest of flood vulnerability and the lowest of it observed in sub-area No. 13. Causes of flood vulnerability in the region include a direct connection to the upstream catchment that has lithology impermeable and geologically impermeable, high-density of building and population, and lack of proportionate open spaces.
Mehrnoosh Ghadimi; sasan zangenetabar
Abstract
One important approach in the management of karst water resources is mapping of karstic aquifers. Vulnerability mapping enables identification of the groundwater resources that are subjected to contamination. The Gilangharb karst aquifer as part of the folded Zagros zone feeds the Gilangharb karstic ...
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One important approach in the management of karst water resources is mapping of karstic aquifers. Vulnerability mapping enables identification of the groundwater resources that are subjected to contamination. The Gilangharb karst aquifer as part of the folded Zagros zone feeds the Gilangharb karstic aquifer. Field visits and examination of chemical properties of the Gilangharb spring all confirm the karstic nature of the study area. In this study, in order to evaluate the vulnerability of the Gilangharb karstic aquifer, the EPIK method consisting of four layers of E (epikarst), P (protective coating), I (penetration) and K (karst network) and also the KDI method based on land use were employed. The former method is one of the inherent vulnerability methods developed especially for the karst areas based on different weight and ranking parameters. After executing the model and preparing the vulnerability map, the EPIK index was calculated between 12 and 26. The spatial distribution of the final vulnerability map classes from the EPIK model shows that 14.24, 14.56, 47.17 and 24.03% of the study area, is located in the low, medium, high and very high vulnerability zones, respectively. According to this map, about 71% of the study area shows high and very high vulnerability indicating high vulnerability of this aquifer. According to the results of the KDI method, 7.54%, 9.49%, 2.9%, 77.89% and 2.18% of the study area had high, medium, low, very low and intact, respectively that shows low vulnerability of the Gilangharb karstic aquifer.
ali dastranj; ahmad nohegar; Arash Malekian; Hamid gholami
Abstract
Abstract Vulnerability assessment and vulnerability mapping, is an important strategy to management of karst water resources. Due to the geomorphology of karst developed in karst aquifers and other natural conditions Azhvan-Bisotun area, Emissions are rapidly and widely. The aim of this study is mapping ...
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Abstract Vulnerability assessment and vulnerability mapping, is an important strategy to management of karst water resources. Due to the geomorphology of karst developed in karst aquifers and other natural conditions Azhvan-Bisotun area, Emissions are rapidly and widely. The aim of this study is mapping vulnerability Azhvan-Bisotun karst aquifer in Kermanshah province against surface contamination by using COP model. According to the aforementioned approach, the COP method considers three factors to assess the resource vulnerability: Overlying layers (O), Concentration of flow (C) and Precipitation regime (P). The results show that the vulnerability of the area between zero and 4.5, respectively, at the end of the five-class very high, high, medium, low and very low were classified. In general, the total area calculated parameters C, P and O have the most significant role in the vulnerability zone. The results demonstrate that COP is a useful method to assess the vulnerability of the test sites under consideration.
