عنوان مقاله [English]
Urbanization and urban development are one of the most important aspects of human civilization, which leads to the transformation of the environment (Ronald, 1973, 5). Urban development occurs in the context of geomorphologic landforms. The geomorphologic hazards and restrictions influence the urban development process and, if not carefully studied, would have detrimental financial consequences on human societies. Cities in the developing world have grown dramatically in the past several decades, with the size of the city of Kermanshah rising sevenfold over the course of four decades. Given geomorphology of the Navidisi Plain of Kermanshah, the city has serious geomorphological limitations for urban physical development. Therefore, zoning and recognizing the areas susceptible to physical development with a geomorphological approach can be the basis for urban development plans and it can lead to proper planning of civil engineering and scientific management of the city. The purpose of this research is to identify the areas susceptible to physical development in Kermanshah city in the future.
Materials and methods
In this research, at first, the physical development in Kermanshah city over 4 decades was determined with the use of Landsat satellite images related to the sensors of MSS and OLI of using the supervised classification method. The map of zoning the areas susceptible to physical development in Kermanshah city using fuzzy model is based on topographic slope parameters, altitude, distance from main faults and sub faults, distance from main waterway, the submarine, lithology, geomorphologic landforms and distance from the city center. The final zoning map of the areas susceptible to physical development in Kermanshah city has been investigated based on land use restrictions.
Results and discussion
Analysis of the urban districts of Kermanshah during the years 1977 and 2017 shows that physical development occurred irregularly in all directions and the city highly physically developed in the northern part of the city between the Ghareh Souz and the highlands of Ankhebahestan. The physical development of Kermanshah city in the last four decades was subject to topographic conditions. The areas in the southern, southwest, and southeastern directions have limited the physical development of Kermanshah to other areas. The physical development of the city over the past 40 years has not followed a particular order. After the fuzzy membership layers are prepared, the nine parameters have been overlaid using the gamma operator 0.8 as the best fitting coefficient and a map was developed of the physical development of Kermanshah. The map was divided into five classes using natural fractures. Four classes with unsuitable condition represent more than half of the study area and the appropriate classes include about 26% of the area.
Inappropriate areas include the highlands of Prao-Bisotun in the north part of the city, the White Mountain in the south part of the city and the area around the Qara-Ansu River in the Kermanshah plain. The inappropriateness of mountainous regions is due to the outcrops of limestone formations, slopes and altitudes, the presence of the main and secondary faults, and the activation geological processes. The urban expansion limits by the Qar-e-Sou River is due to the loose river sediments, the risk of flooding and the existence of the original Qara-Sos fault. The mountainous areas are also not suitable for physical development due to the presence of topographical and lithological limitations. Suitable areas can be suggestedfor alluvial plain with appropriate topographic conditions and outcrops of quaternary deposits and a suitable distance from faults and drainage networks. The area of the zones suitable for urban development after land use interference and the distance from the city is about 50 square kilometers. Given the appropriate distance from faults and waterways in suitable topographic areas and mainly on quaternary deposits is located in the alluvand plain in the west and east Kermanshah. Finally, it can be argured that the current range of the city of Kermanshah, as well as the surrounding areas due to geomorphologic conditions, has the risk of destructive hazards over the past few decades. The physical development of Kermanshah has occurred with no regard to these restrictions. Therefore, a comprehensive plan for the high risk areas of Kermanshah city has been developed and then proposed areas for the urban development of the city is presented according to the socio-economic conditions.