Elham Forootan
Abstract
Extended AbstractIntroduction. Floods are natural disasters which occurrence causes annual great damage to people and environment around the world. So, specifying flood susceptible land is a necessity to reduce and control destructive impacts. Watershed management implementations could affect runoff ...
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Extended AbstractIntroduction. Floods are natural disasters which occurrence causes annual great damage to people and environment around the world. So, specifying flood susceptible land is a necessity to reduce and control destructive impacts. Watershed management implementations could affect runoff volume and flood occurrence. The goal of this study is to apply the combination of Curve Number method and AHP in Arc-GIS to prepare flood susceptibility map and to investigate the role of biological measures in flood susceptibility of the region through this method and statistical tests.Materials & Methods .For this purpose, Pardisan watershed located in the southern part of Qom city was selected. Ten factors layers viz. drainage density, slope, annual rainfall, distance from river, elevation, flow accumulation, SCS Curve Number, geo infiltration, geomorphology and previous floods were prepared and classified based on flood susceptibility in different scales. Then future Curve Number was determine with assuming the implementation of biological watershed management in different land uses such as rangeland, agriculture, garden and badland. In this study, AHP method in Arc-GIS was used to calculate pairwise comparison and determine the weight of each factor. Overlaying current and future Curve Number layers with nine layers using the weights obtained from the hierarchical analysis method led to the preparation of flood susceptibility maps for pre and post watershed management implementation. Results & DiscussionGeo infiltration map showed the proportion area of “low”, “and “very low” infiltration classes were 4.46% and 16.87%, respectively while moderate and high infiltration classes were 39.75% and 38.92%. Slope map indicates that 0-2%, 2-5%, 5-15%, 15-35% and 35-60% classes comprise 29.87%, 35%, 30.11%, 4.88% and 0.14% of the studied area, respectively. In this region, South parts were steep whereas; north parts were mild. Distance to river is another factor classified in to four groups of 0-500, 500-1000, 1000-3000 and 3000-6500 meter with 38.86%, 24.32%, 29.63% and 7.19% of the region, respectively. Elevation classified map revealed 45.1% of the region were in 900-1200 meter range whereas; 36.4%, 14.8%, 3.6% and 0.1% were in 1200-1500,1500-1800,1800-2100 and 2100-2400 meter classes, respectively. As can be seen in rainfall map, 25.57% of the region was categorized in 140-160 mm rainfall class while 35.41%, 20.59% and 18.43% of the whole area were classified in 160-180,180-200 and 200-250mm groups. In the region, South parts have more rainfall volume than north. Also, flow accumulation map indicated that 96.5%, 1.97%, 1.07%, 0.24% and 0.22% were classified as 0-1500, 1500-5000, 5000-15000, 15000-25000, 25000-100000 values which high flow accumulation pixel range show high flood susceptibility. Drainage density map represents 10.38%, 14.36%, 56.88% and 18.38% of the studied area were grouped in 0-0.05, 0.05-0.07, 0.07-0.09 and 0.09-0.12 classes. Also, Curve Number (SCS) map for garden, cultivated lands, rangelands and badlands shows that 25.54% of the study area was classified as 15-35 CN value while 36.14%, 0.9% and 37.42% were categorized in 35-50, 50-65 and 65-80 classes before performing biological measures. After biological measures in different uses, 15-35 Curve Number values are observed in 36.6% of the area and 35-50, 50-65, 65-80 classes comprise 32.05%, 29% and 2.35% of the study area, respectively. The geomorphological map shows that the class with the highest score is visible in 68.96% of the area, while the classes with the lower scores are observed in 3.07, 18.34, 9.37, and 0.26% of the region, respectively. The past flood zoning map of the region also shows that 22.41% of the region exist in low susceptibility class, 36.15% of the region locates in the medium susceptibility class and 41.44% is in the high sensitivity class. For AHP approach, the calculated consistency ratio of this study was less than 0.1. Therefore; the compatibility between ten selected factors was acceptable. AHP results showed that the Curve Number factor has the highest weight percentage (27.44) whereas; the geo-infiltration has the lowest weight percentage (3.20). Comparison of flooding classes for pre and post water management implementation shows that high and medium flooding classes will decrease by 7.3 and 39.7% and low and very low susceptibility classes will increase by 22.18 and 24.82 %, respectively due to the implementation of biological watershed management measures. Also, Sign and Wilcoxon statistical tests indicated the existence of significance difference in flood classes’ for pre and after implementing biological watershed management. ConclusionFlood susceptibility map provision is a necessity in arid and semi-arid regions due to insufficient vegetation cover. The results of this study indicate positive effects of biological watershed management in decreasing flood vulnerability. These findings can be considered for future planning of the region and help watershed managers for optimal utilization of water and soil resources and reduction of flood damage.
Geographic Information System (GIS)
Mohamad Amin Daneshfar; Mehdi Ardjmand
Abstract
Extended AbstractIntroductionSuitable sites for waste disposal must leave the least environmental effects while being executable in various aspects. Combination of AHP and GIS is a popular approach used for selecting suitable waste disposal sites, since AHP classifies and prioritizes selected sites ...
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Extended AbstractIntroductionSuitable sites for waste disposal must leave the least environmental effects while being executable in various aspects. Combination of AHP and GIS is a popular approach used for selecting suitable waste disposal sites, since AHP classifies and prioritizes selected sites based on different types of information layers and GIS provides an effective way for data management and display. Various studies have been recently conducted to select suitable sites for waste disposal using GIS and AHP. Rahimi et al. selected a sustainable site for urban solid waste disposal in Mahallat, Iran, using AHP and GIS. Fourteen environmental, economic and social parameters affecting sustainability of landfills were examined in this study and a site was selected in vicinity of this city as the most suitable landfill for solid waste disposal. Improper disposal of waste produced in oil-based drilling of oil and gas wells not only increases costs, but also cause the aforementioned problems. Thus to prevent these problems, it is necessary to select appropriate landfills for this kind of waste.Although, Iranian Offshore Oil Company (IOOC) is responsible for most of oil and gas extraction from Iranian fields in the Persian Gulf, no specific solution has been provided for selection of suitable locations for drilling waste produced in these areas. The present study seeks to select suitable sites for disposal of drilling waste produced in east of the Persian Gulf Iranian oil and gas fields in Lavan Island using AHP method and GIS software. Material and methods Case study Oil and gas fields in Qeshm, Kish, Siri and Lavan operational areas are located in the eastern part of the Persian Gulf. Lavan is one of the islands of Hormozgan province in the Persian Gulf. It is about 2.5 kilometers long and 4.8 kilometers wide. Oil Based Drilling Fluid used in Iranian Oil and Gas Fields in the Persian GulfDue to the type and depth of formation (layers of shale and deep reservoirs), oil based drilling fluids are generally used in Iranian oil and gas fields in the eastern Persian Gulf (Qeshm, Kish, Siri and Lavan). The main component of oil based drilling fluid is petroleum hydrocarbons, especially those with high flashpoint. Usually diesel fuel is used as the main component, which may be added up to 90% to the fluid used in drilling operations. Drilling waste produced in Iranian oil and gas fields in the Persian GulfBased on the latest statistical information provided by IOOC, annually drilling waste is generated by this company in the Persian Gulf, which has declined in recent years due to a reduction in excavation activities. The volume fractions of humidity and oil in the drilling waste are 65% and 30%, which according to the standards of Iranian DOE and HSE unit of IOOC must be reduced to 15% and 1%, respectively after the recycling process. Analytic hierarchy processThe analytic hierarchy process (AHP) is a logical framework that divides complex decisions into hierarchical structures and thus, simplifies their understanding and analysis. This process can be used when decision-making faces some alternatives. GIS Site selection in land-related sciences is an operation through which an expert presents needs, objectives, and information related to the current situation to find the best choice among available alternatives for the concerned land use. The main objective of site selection is to ensure that considering all limitations and available facilities, human activities in the selected site is consistent with the surrounding environment. Nowadays, GIS is used to reach a more scientific and realistic site selection. GIS is a coherent system of hardware, software, data, which allows the storage, analysis, transfer, and recovery of input data and makes it possible to publish the output data as maps, tables, and models of geographical zones. MethodologyThe present study is applied in terms of its objectives and descriptive-analytical in terms of its methodology. The criteria and sub-criteria (layers) involved in site selection for drilling waste disposal in Lavan Island were chosen based on the specifications of the region, recommendations of experts, and related literature. Base data were collected from various sources such as IOOC, Iranian department of environment, and geological survey and mineral exploration of Iran. Accordingly, 15 information layers (sub-criterion) affecting waste disposal site selection in Lavan Island were introduced and classified into three indices. These information layers include industrial building, slope, elevation, gas lines, oil lines, oil storages, roads, population centres, industrial regions, land use, airport, fault line, vegetation, river, and geology which have been classified as technical-economic, social-cultural, and environmental indices (criteria). Figure 1 depicts the hierarchical tree of site selection for disposal of drilling waste produced in eastern Persian Gulf Iranian oil and gas fields in Lavan Island. Figure 1. The hierarchical tree of site selection for oil based drilling waste in Lavan Island Results and discussionProperties of each layer (layer values) were weighted in GIS environment based on al-saati method and experts’ opinions. Classification, weighting and normalization of effective layers used for selecting appropriate sites for oil drilling waste disposal in Lavan Island were performed and results were used to prepare a weighed map for each layer. These maps were combined in the final step to obtain the proposed map for waste disposal site. Figures 2 shows the weights assigned to information layers prepared for waste disposal in lavan Island. Figure 2. Weights assigned to information layers prepared for oil based waste disposal in lavan Island After the internal weighing of each layer, the AHP model was used to prepare the final map for the optimal site. Weighing each of these 15 layers is one of the most important stages of this model in which significance of each layer is expressed compared to other layers. The ultimate normalized weight of each layer was calculated by an AHP matrix with an inconsistency rate lower than 1.0. Chart 1 shows the ultimate normalized weight of each layer which will be used in overlapping operations to find appropriate sites for oil based drilling waste disposal in Lavan Island. Chart 1. Importance of weights assigned to layers in the selection of oil based waste disposal site in Lavan IslandResults indicate that distance from population centers, distance from roads, distance from rivers and distance from airport are the most important parameters used to select appropriate sites for oil based waste disposal in Lavan Island. Results confirm the sensitivity of environmental and socio-cultural criteria for oil based drilling waste disposal in Lavan Island.Then, information layers were integrated using weighted overlay method in AHP to obtain the final map of the appropriate region for waste disposal. In this stage, the layers were overlapped based on their level of effectiveness in GIS environment and the final site selection map was prepared for waste disposal in Lavan Island (see Figure 3). The appropriate sites for waste disposal were classified into 5 classes (from “very good” to “very poor”) and depicted in this map. Figure 3. Classification of selected sites for oil based waste disposal in Lavan Island Spatial analysis of final maps shows that some regions in the center of Lavan Island (sites number 1, 2, 3, 4 and 5)are appropriate for drilling waste disposal due to their distance from population centers, roads, rivers, and the airport. These barren lands are the farthest sites from urban centers, roads, rivers, and the airport. Therefore, construction of waste disposal sites in these regions of Lavan Island is suggested in the final map to decision-makers. Figure 4 shows the prioritized waste disposal sites in Lavan Island. Figure 4. Prioritization of oil based waste disposal sites in Lavan Island ConclusionsThe present study was performed due to the lack of similar studies on waste disposal site selection in this region. GIS and AHP were used to select suitable sites for the disposal of drilling waste in Lavan Island. This drilling waste is produced in the Iranian oil and gas fields in the eastern parts of the Persian Gulf. Effective factors were weighted in different layers of GIS environment and weighted maps were prepared. Priorities were selected using the AHP, and site selection for drilling waste disposal was performed in GIS. Distance from rivers was recognized as the top priority parameter in environmental criteria due to the importance of environmental standards and avoiding surface water pollution. Moreover, distance from population centers, roads, and the airport were selected as top priorities in social-cultural sub-criteria due to the importance of the Island residents’ health and beauty of the landscape. Information layers were thus produced and combined using weighted overlay method in AHP to reach the final maps of suitable locations for oil based waste disposal in GIS. In accordance with effective criteria in the waste disposal site selection, suggested sites were classified into five classes ranging from “very good” to “very poor”. Accordingly, some sites located in the central part of Lavan Island were selected as appropriate sites for the disposal of drilling waste due to their distance from urban and population centers, roads, rivers, the airport, and so forth
Mehrdad AhangarCani; Mohammad Reza Malek
Abstract
Extended Abstract
Introduction and Objective
Road traffic accidents impose numerous social, economic, and cultural costs upon various societies, especially developing countries. Identification of accident blackspots is a method proposed to deal with car accident risks. Among various events associated ...
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Extended Abstract
Introduction and Objective
Road traffic accidents impose numerous social, economic, and cultural costs upon various societies, especially developing countries. Identification of accident blackspots is a method proposed to deal with car accident risks. Among various events associated with transportation network, road traffic accidents play a significant role, because of their specific features, including high frequency, high intensity and the chance of direct involvement of all members of the community.This problem is more conspicuous in developing countries such as Iran. The present study aims to identifyaccidentblackspotsand to prepare risk map for road trafficaccidents in Babol city using volunteered geographic information.
Materials and methods
According to the characteristics of the study area, the present study takes advantage of criteria such as distance from population centers, proximity to city squares, distance from footbridges, and proximity to road intersections to identifyaccidentblackspotsand a prepare risk map for roadtraffic accidents in Babol city. Accident blackspots detected by volunteered geographic information, along with the criteria determined by applying analytic hierarchy process (AHP) and analytic network process (ANP) were compared in a pairwise manner, and their respective weight was calculated to showtheir specific level of impact. Ultimately, a risk map was produced for the risk of road traffic accidents obtained from each method. In order to evaluate the accuracy of the identified accident blackspots obtained from volunteered geographic information, as well as the accuracy of susceptibility maps, ROC curve and Kappa Coefficient were applied to police official records.
Results and Discussion
According to the findings, Jame Mosque shopping center, Shahabnia shopping center, intersection of Farhangstreet and Velayat square were identified as the most accident-prone areas in Babol city. Also, among the prespecified criteria, distance from population centers and distance from intersections are considered to be the most important criteria, respectively. Results obtained from the evaluation criteria indicatedhigh accuracy of volunteered geographic information, and thus it is concluded that this kind of information can be effective in determining the accident blackspotsinBabol city. Also, the ANP method works better than AHP method in preparing the risk map of accidents.
Conclusion and Future works
Due to the large number of road accidents, especially in developing countries,the issue of accident blackspotsand providing a risk map for road trafficaccidents are an essential part of roads safety. In the present study, volunteered geographic information was used, along with multivariate decision-making methods of analytic hierarchy process (AHP) and analytic network process (ANP) to identifyaccident blackspots based on number, causes and severity of accidents and to develop a risk map for driving accidents in Babol city. Moreover, the criteria of distance from population centers, proximity to the city squares, distance from the footbridges, and adjacency to intersections were used to determine accident blackspotsand to prepare a risk map for driving accidents in Babol city. According to the results, Jame Mosque shopping center, Shahabnia shopping center, Farhang intersection and Velayat square were identified as the most accident-prone points in Babol city. Also, distance from population centers and distance from intersectionswere identified as the most important criteria, respectively. Evaluation criteria demonstrated that volunteered geographic information can be effective and accurate in determining accident blackspotsinBabol city. Also, the ANP method worked better than AHP method in preparing the risk map of driving accidents. The method proposed in this study to identify accident blackspots and preparedriving accidents risk maps can be generalized to other areas. Basedon the characteristics of specific routes, other criteria such as arc radius, longitudinal slope can alsobe used. It is also suggested that the results of other methods used for investigation ofaccidentblackspotsand production of risk maps based onvolunteered geographic information (VGI) are compared with the results of the present study.
Zeynab Aliabadi; Mahid Nastaran; Farzane Pirani; Farzane Sheikhzade
Abstract
Extended Abstract Introduction The deployment of every urban element in the position of the body - a particular area of the city - is subjected to certain principles, rules and procedures that, if followed, will ensure the success and effectiveness of thatelement in the same place, otherwise there will ...
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Extended Abstract Introduction The deployment of every urban element in the position of the body - a particular area of the city - is subjected to certain principles, rules and procedures that, if followed, will ensure the success and effectiveness of thatelement in the same place, otherwise there will be many problems with the occurrence it does.Therefore, achieving equilibrium in the spatial distribution of resources and services is the main goal of the planners. Considering the importance of locating and its position in various projects, the importance of the location of the fire stations and the direct impact on its model and performance will be determined. Provision of fire station services requires their proper location in order to distribute them appropriately to minimize their financial losses.Locating fire stations and determining the number and location of stations guarantee the safety of citizens in the event of any incident. Due to the high importance of the 3rd district of Isfahan among other areas of the city, attentionto safety issues in this context is urgently needed. The 3rd district of Isfahan is the heart of the city which has an ancient heritage. One of the important issues facing urban management is the timely delivery of firefighting during a fire.There was no responsive station in this area. Thus, the need to address the problem of locating and distributing fire stations is of great importance in urban planning. Therefore, the choice of optimal location and appropriate distribution of fire stations will bethe overall goal of this study to increase the safety level. Materials & Methods The present research is a descriptive-analytic research in terms of purpose, and an applied research in terms of the nature and method of the study. Part of the theoretical information was collected through library studies, the use of documents, records and reports. To understand the scope, the studies conducted by the consultant as well as field observations and observations have been used. In the analysis section, using Analytic Hierarchy Process (AHP) and geospatial mappingmodel. In this study, at first, the criteria and the sub criteria for determining the location of the fire station were weighed by the Analytic Hierarchy Process (AHP) using Expert Choice software, and then, by digitizing the layers in the GIS, eachmap layer was produced for each of the criteria, and then the layers were overlapped by applying the weights of each layer, and the fire station's optimal locations are proposed. Results & Discussion Among the urban facilities, the construction of fire centers in the area due to the deployment of the old, historical and living Qaiseriyah market, and the lack of emergency exit routes and relief during the fire, as well as the existence of workshops and warehouses connected to the market, it is also important that it should be added to the consequences of other incidents. Therefore, this study was aimed at increasing the level of safety by locating fire stations in Isfahan's region 3using AHP and location model in GIS environment. After normalizing the maps with the Reclassifying tool, and according to the categories at this stage with the Raster Calculator tool, the sum of all generated layers multiplies the values for each layer obtained from AHP andmaps of the proposed locations for Fire station was created. Based on the final map (Figure 19), the most suitable optimal points for the fire station were selected based on the criteria analysis. These points of choice have the proper features, including proximity to access level 2, abandoned land, an area of 1500 square meters up, construction density and high population density in the periphery. According to (Fig. 19), three-point distances were investigated using the Euclidean Distance tool. On the other hand, according to the existing standard, for every 50,000 people we need to build a fire station; therefore, in addition to a fire station in the area, it is necessary to deploy another station. Finally, according to the aforementioned maps, by examining the intervals between the existing and proposed fire stations, the final map (Fig. 20) is based on the noninterference of the functional radii of 1200 meters of stations relative to each other; the third point was deployed as the optimal and the most common location of the firestation. Conclusion By studying the present situation and field observations of the fire stations in Isfahan's region 3, it has only one center, and according to the volume of utilizations and activities of importance in the region as well as theheight of the region with historic monuments at national and international levels, the issue of safety in the context of this region is very important. Therefore, based on the population and region level, the existing fire station does not cover the possibility of service within a 3-5 minute interval throughout the entire area. Considering that the area has organic and intact texture. Based on field observations and existing standards, residents need urban equipment, including fire stations. Therefore, the purpose of this study was to locate another fire station based on the region's requirements, standards and indicators. Therefore, effective measures in area 3 including demographic density, availability, consistent use, functional radius, building quality, size of parts, construction density, and user-friendliness were considered. Eventually, considering the 1200 meter radius, the location of the optimal fire station was proposed on Neshat Street.
Rahim Sarvar; Iraj Yahyapoor
Volume 23, SEPEHR , July 2014, , Pages 80-88
Abstract
With increasing growth of urban population and urban development, the necessity of building new public service centers and determining an optimal place for them have become obvious. Due to dramatic increase in population, chaotic development of the city, and increase in the number of vehicles manufactured ...
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With increasing growth of urban population and urban development, the necessity of building new public service centers and determining an optimal place for them have become obvious. Due to dramatic increase in population, chaotic development of the city, and increase in the number of vehicles manufactured in the metropolis, Tehran faces a shortage of appropriate places for parking vehicles in crowded areas. Optimal locating of public parking lots is an approach and solution for traffic dilemma. Geographic information systems and Boolean logic are appropriate systems for finding the most optimal place for building Multi-story parking lots. This article investigates and evaluates multi-story parking lots in Tehran 15th district, considering parameters like attractive centers for travelers, access networks and urban passages, quality-structure, traffic junctions, different useful land uses, etc. Analytic hierarchy process (AHP) was used to weight the above mentioned parameters, and Boolean logic was used to overlap produced layers. After applying final weights retrieved from AHP model and overlapping produced layers, optimal sites for locating Multi-story parking lots were determined. Finally, suggestions were proposed according to the results and requirements of time and space.
