بررسی و تحلیل عوامل انسانی و محیطی موثر بر آسیب‌پذیری روستاها در برابر سیل سال 1396شهرستان عجب‌شیر

خطر سیل و تلفات حاصل از آن، یکی از تهدیدهای اصلی در سکونتگاه ‌های روستاهای ایران است که تحت ‌تاثیر عوامل متعدد محیطی و انسانی رخ می ‌دهد، ولی در بررسی ‌های سیل معمولاً به عوامل محیطی توجه می ‌شود و عوامل انسانی کمتر قابل توجه قرار می ‌گیرد. پژوهش حاضر با هدف مطالعه نقش عوامل محیطی و انسانی بر وقوع سیلاب در حوضه آبخیز قلعه چایی در روستای عجب شیر و بر اساس تجارب سیل 1396 صورت گرفت. داده ‌های مورد نیاز پژوهش به دو صورت داده ‌های محیطی و انسانی جمع ‌آوری شد. روش مورد استفاده در داده‌ های محیطی نیز استفاده از نقشه‌ های جغرافیایی متعدد مانند کاربری، توپوگرافی، شیب، آبراهه و ... است و در بخش انسانی از پرسش‌نامه و نتایج آن استفاده شد. جامعه آماری این تحقیق، خانوارهای ساکن در 36 روستا است که با استفاده از روش کوکران و به روش خوشه ‌ای، 378 نفرآنها به عنوان نمونه انتخاب شد. نتایج استخراج شده از تجزیه و تحلیل نقشه ‌های جغرافیایی از نظر شدت تخریب و تعداد کشته ‌های سیل سال 1396 نشان داد که بیشترین میزان سیل خیزی در روستاها تحت ‌تاثیر شیب، توپوگرافی و نزدیکی روستا به بستر رودخانه بود. نتایج تحلیل داده‌ های انسانی هم نشان داد که عواملی مانند تجربه قبلی سیل، مهارت های کسب شده در تقابل با وقوع سیل و درآمد و زیرساخت ها، با میزان آمادگی روستاییان در برابر سیل همبستگی معناداری قوی تری دارد. نتایج آزمون واریانس نیز نشان می ‌دهد که از نظر عوامل انسانی و محیطی موثر در آسیب‌ پذیری روستاها در برابر سیل، اختلاف معناداری وجود دارد. بنابراین با توجه به عوامل انسانی و محیطی، پیشنهادهایی کاربردی مبتنی بر اقدامات عملی پیشگیری از سیل در محدوده مورد مطالعه ارائه شد.

Investigation and Analysis of Human and Environmental Factors Affecting the Vulnerability of Rural Settlements to Floods in 2017 in Ajabshir County

1 IntroductionOver the past few decades, a variety of methods have been developed to study flooding, including the most important flood risk estimation methods proposed by researchers such as maximum possible flood risk and flood frequency analysis. In addition to the mentioned methods, that are methods which are mainly based on the use of GIS and remote sensing technologies and seek to investigate the flood situation using environmental parameters. It seems that the study of flood risk beyond natural phenomena is also related to human factors. In this regard, studies conducted on multiple floods show that despite the high efficiency of software in assessing hazards, none of these cases in practice has been able to prevent the occurrence of refloods and the resulting losses. Human factors are also effective in the occurrences of floods. Considering the mentioned cases and the necessity of investigating the possibility of occurrence of floods and also the great importance of investigating the role of human elements along with environmental factors in the happenings of floods, the present study was conducted with the main purpose of investigating and analyzing the role of environmental components and humans in the occurrence of floods in Qaleh Chaie, which was taken from the experiences of floods in 2017.2 MethodologyThe present research, in terms of method, has an applied purpose and a descriptive contextualized nature. To collect the required data for the research, the library and field methods (researchermade questionnaire in a fivepoint Likert scale) as well as the experts #39; questionnaire (Delphi), were used. The implementation process of this research has been done in two general stages: in the first part of the research, the parameters affecting the risk of flood occurrence were environmental. The software used in this section was ARC GIS and ENVI software. Components used in this section include land topography (height), land slope, slope direction, distance from the river, vegetation density, flood characteristics, rainfall, and land use. Also, in the environmental component section, economic, sociocultural, structuralinstitutional, and infrastructural variables have been used. The collected data were analyzed using statistical tests.3 Results The results of the analysis of satellite images in the field of topographic parameters of the land slope, slope direction, height, and distance from the Ghaleh Chaie River and others show that there is a big difference in different villages. The first group of villages that are located in the direction of Ghaleh Chaie are prone to floods due to the mountainous type of the region and also the steep slope, and the other group that is located at the end of the Ghaleh Chaie watershed has a very gentle slope due to its plain location and villages are less prone to face floods. Also, the results showed that from 1971 to 2017, 9 floods were reported in the area. In other words, the return periods of the floods are about six years. Also, since 1971, three floods have been reported, which killed four people in 1979, eleven people in 1990, and twenty casualties in 2017.The results of oneway analysis of variance showed that the difference between 36 villages in terms of four indicators affecting flooding was significant at the level of 0.000, coefficient of 0.05%. Among these, the variables related to economic effects with the value of F = 13.524 have the highest level of expectation from the other three groups, followed by infrastructure, culturalsocial and structuralinstitutional variables, respectively.The study of the spatial distribution of the villages indicated that the villages near the Qaleh Chain River are vulnerable due to the high slope of the land, the mountainous nature of the region, the melting of snow, and the flow of water due to rainfall on the slopes of Sahand Mountain. Most of these villages are prone to be affected by environmental factors like slope, proximity to the river, mountainous topography, and so on. 4 Discussion ConclusionAs it has been examined in this study, given that floods are recognized as one of the most destructive natural disasters in the world, the identification and investigation of areas vulnerable to floods as well as the identification of all natural and human components that might influence the occurrence of this this phenomenon can be the starting point for practical and effective planning in the field of flood prevention. Accordingly, in this research, the role of environmental and human factors in the occurrence of floods have been investigated simultaneously. The results show that villages located in mountainous areas with high slopes are very vulnerable to flooding. Since environmental parameters are beyond human control, their effects can be reduced by taking preventive measures. The results also showed that there is a relationship between human parameters and the degree of vulnerability of villages to floods, so it is suggested that to manage flood risk in rural areas, human and environmental components be taken into account and studied simultaneously.