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

Over 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 re-floods 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.

The 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 (researcher-made questionnaire in a five-point Likert scale) as well as the experts' 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, socio-cultural, structural-institutional, and infrastructural variables have been used. The collected data were analyzed using statistical tests.

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 one-way 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, cultural-social and structural-institutional 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.

As 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.