Parastoo Karimi; Masoud kherkhah zarkesh; Payam Alemi Safaval; Zahra Azizi; Hossein Yousefi
Abstract
In the last decade, the use of remote sensing has played an important role in identifying and assessing natural disasters, especially floods. Among these techniques, the Support Vector Machine algorithm (SVM) and Change Detection technique can be mentioned. The main objective of this study was to evaluate ...
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In the last decade, the use of remote sensing has played an important role in identifying and assessing natural disasters, especially floods. Among these techniques, the Support Vector Machine algorithm (SVM) and Change Detection technique can be mentioned. The main objective of this study was to evaluate the capability of these techniques in determining the effects of flood in Gori Belmak Wetland and Poldokhtar triple wetlands in the north of Molab and outlet of Poldokhtar watersheds in Lorestan Province, which was faced with flood in April 2019. The land use maps of the region were prepared by applying supervised classification method and the SVM on the Landsat 8 satellite image in the 2013, 2015, 2017 and 2019. Validation of the maps and techniques using indicators of kappa and overall accuracy, showed the high accuracy of maps prepared. The kappa coefficient was calculated to be 0.87, 0.84, 0.83 and 0.87 for the maps of the studied years and the overall accuracy was 90.02, 89.51, 88.11 and 90.32, respectively. By extracting the water class, the changes that occurred on the water body of the wetlands were detected. The results showed that Gori Belmak Wetland, undergo extensive changes due to reasons such as drought in 2015, increase of 112.08 ha of surrounding arable lands between 2013 and 2019, as well as topographic features, especially lower slope than the three wetlands. In 2019, with the storage of flood, this wetland increased to 47.08 ha compared to 2017 and reached an area of 146.15 ha. The similarity of the results obtained in this study with the results of the research conducted in the study area by the Copernicus Emergency Management Service (EMS) and the Geoinformatics Unit research team on the flood of 2019 indicates the high accuracy of the used techniques and results of the present research.
Amir Sarreshtehdari; Amin Salehpour Jam; Mohammad Jafar Soltani; Aliakbar Noroozi; Alireza Shademani; Masoud kherkhah zarkesh
Abstract
Determining the effectiveness of flood spreading schemes, especially from the point of view of effective economic and social indicators, over a quarter century after their implementation in the country, plays an important role in their assessment. In this study, indicators related to the effects of flood ...
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Determining the effectiveness of flood spreading schemes, especially from the point of view of effective economic and social indicators, over a quarter century after their implementation in the country, plays an important role in their assessment. In this study, indicators related to the effects of flood spreading plans on Ab-Barik Aquifer of Bam were identified and then ranked based on nonparametric statistical tests from the experts' point of view. For this purpose, first the indicators related to the effects of flood spreading projects on the aquifer based on library studies, expert inquiries as well as site visits and face-to-face interviews with local residents and users were identified and finally the validity of the questionnaire based on expert opinions was identified. Finally, the validity of the questionnaire based on the experts' opinions and their comments was finally confirmed. Also, the reliability of the measuring instrument was tested by calculating Cronbach's alpha component. In this research, based on the multi-response coding method, the variables of the questionnaire were of the type of qualitative and qualitative variables consistent with the Likert scale, so at this stage, a survey was conducted from 30 experts. The range of changes in mean rank values varies from 4.15 to 22.88. The results of the ranking of indices based on Friedman test showed a significant difference in the effectiveness of the effective variables in evaluating flood spreading projects on aquifer, so that the question of “reducing the damage to flood lands and gardens” with the rank mean of 22.88 and also the question of “conflicting among the villagers in the area” with the rank mean of 4.15 have maximum and minimum priority, respectively. In addition, the results of the study indicate the high effectiveness of flood spreading schemes in the Ab-Barik Aquifer of Bam.
