Document Type : Scientific Research
Authors
1 Ph.D. Candidate of Geomorphology, Tehran University
2 M. A Hydrogeomorphology, Tehran University
3 M.A. Political geography, Ferdosi University
Abstract
Highlights
The physical expansion of cities is inevitable, which can pose risks over time. Depending on the tectonic, hydro-geomorphological and climatic conditions, the type of hazards will vary in different regions. Since the occurrence of hazards especially in urban areas can be associated with a large number of casualties and financial losses, it is necessary to investigate and identify the types of hazards in urban areas. Therefore, the present study was conducted to evaluate the risks facing the study area. In previous studies, urban areas have been mainly evaluated for the likelihood of a hazard or the areas with low potential for urban expansion have been identified. However, unlike many previous studies, this study identifies the types of potential hazards for the study area. The results of the evaluations indicate that the study area is susceptible to three hazards of subsidence, flood, and slope movements. In fact, in recent years, the trend of overuse of groundwater has resulted in an average drop of 0.5m in Qorveh plain which is a very high figure, and this has caused the study area to have a subsidence of about 47 mm in the southern margin of the city of Qorveh as well as the margins of the Qaleh River over a period of two years (2016.01.11 to 2017.12.19). Therefore, one of the dangers of the advancement of the study area is subsidence induced hazards, which are less felt as they occur gradually but can, in the long run, cause significant damage to residential areas and heavy construction. Another threat to the study area is the risk of possible floods. In recent years, the physical expansion trend of the city of Qorveh and the Qaleh discontinuous urban area has been directed towards the River Qaleh, which has caused many residential areas to be exposed to floods. Also, the potential hazards arising from the slope movements are considered as another hazard in the study area. In fact, in recent years, the physical expansion trend of a part of the city of Qorveh towards the slopes of the Kolava Mt. has caused some of the western areas of the city of Qorveh to be exposed to the risk of slope movements. The mentioned matter indicate that Qorveh city is subjected to subsidence from the south and margins of the Qaleh River; exposed to flooding from the riverside and the west side it is subject to slope movements indicating that urban geomorphology is neglected in site selection of a part of the study area’s residential area. The study area is one of the residential areas. The above shows that the town of Qorveh has a subsidence potential from the south and the River Qaleh. On the riverside, it is exposed to floods and from the west, there is the potential for range movements indicating a lack of attention to the principles of urban. Therefore, it is necessary to prevent the movement of these areas into vulnerable areas in future planning to reduce the vulnerability of residential areas to potential hazards. According to the results of the present study, the following suggestions are made:
- Identification of areas prone to geomorphological hazards
- Preventing urban expansion towards hazardous areas
-Determining appropriate directions for future physical expansion of the city
- Raising awareness of residential areas at risk
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Main Subjects