پهنه بندي مناطق مستعد توسعه شهري با تأكيد بر محدوديت ها و مخاطرات ژئومورفولوژيكي (مطالعه موردي: شهر كرمانشاه)

Zoning of areas prone to urban development with emphasis on geomorphological limitations and hazards (Case study o Kermanshah city)

شهر كرمانشاه، به عنوان بزرگترين شهر غرب كشور، در پهنه هاي دشت پُرمخاطرة كرمانشاه واقع شده و در بازة زماني 46ساله مساحت آن حدود 7 برابر شده و حدود 87 كيلومترمربع به تصرف شهر درآمده است. اين توسعة فيزيكي بدون اجراي مطالعات ژئومورفولوژيكي و درنظرگرفتن محدوديت ها و مخاطرات ناشي از آن بوده است. ازاينرو، شناسايي مناطق مستعد توسعة فيزيكي با درنظرگرفتن محدوديت ها و مخاطرات ژئومورفولوژيكي امري لازم در توسعة شهري كرمانشاه است. هدف از پژوهش حاضر شناسايي مناطق مناسب براي توسعة فيزيكي شهر كرمانشاه براساس شرايط ژئومورفولوژيكي منطقه است. در اين پژوهش با استفاده از مدل فازي نقشة پهنه بندي نهايي توسعة شهري براساس نُه پارامتر مؤثر تهيه شد. سپس، اين نقشه براساس شرايط ژئومورفولوژيكي و كاربري اراضي دشت كرمانشاه ارزيابي و مناطق مستعد توسعة شهري پيشنهاد شد. نتايج نشان ميدهد توسعة فيزيكي شهر كرمانشاه در طي چهار دهة گذشته تابع شرايط توپوگرافي بوده و مخاطرات و محدوديت هاي ژئومورفولوژيكي بسيار زيادي در محدودة مورد مطالعه وجود دارد؛ بهطوريكه 65 درصد مساحت منطقه براي توسعة شهري مناسب نيست. مناطق مساعد با حدود 50 كيلومتر مربع در دشت آبرفتي در غرب و شرق شهر كرمانشاه واقع شده اند.

Introduction Urbanization and urban development are one of the most important aspects of human ivilization, which leads to the transformation of the environment (Ronald, 1973, 5). Urban development has occurred in the context of geomorphologic landforms, which has the effect of geomorphologic hazards and restrictions on the urban development process and, if not carefully studied, would have harmful financial and 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. In terms of geomorphology of the Navidisi Plain of Kermanshah, Kermanshah 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 the preparation of urban development plans and lead to proper planning of civil engineering and scientific management of the city.The purpose of this research is to identify areas susceptible to physical development in Kermanshah city in the future. materials and methods In this research, at first, the amount of physical development in Kermanshah city over 4 decades was determined with the use of MSS and OLI satellite images of Landsat by using the supervised classification method. The map of zoning of areas susceptible to physical development in Kermanshah city using fuzzy model based on topographic slope parameters, altitude, distance from main faults, distance from sub faults, distance from main waterway, distance The submarine, lithology, geomorphologic landforms and distance from the city center were prepared.The final map of the zoning of areas susceptible to physical development in Kermanshah city has been investigated based on land use restrictions and ultimately areas susceptible to the city's physical development in the future. Findings Determining the districts of Kermanshah during the years 1977 and 2017 shows that physical development occurred in all directions and the most physical development in the northern part of the city was the boundary 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 and only rugged areas in the southern, southwest, and southeastern directions have limited the physical development of Kermanshah to other areas, and the physical development of the city over the past 40 years has not followed a particular order. After preparing the fuzzy layers, the nine parameters using the gamma operator 0.8 were used 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. The floor with a very low proportion represents more than half the area of the study area and the appropriate classes include about 26% of the area. Conclusion Inappropriate areas include the highlands of Prao-Bisotun in the north of the city, the White Mountain peaks in the south of the city and the area around the Qara-Ansu River in the Kermanshah plain. The inappropriateness of mountainous regions due to the outcrops of limestone formations, slopes and altitudes, the presence of the main and secondary faults, and the activation of forming processes such as the fall of parts and blocks of lime. The limits of the Qar-e-Sou river due to the loose river sediments, the risk of flooding and the existence of the original Qara-Sos fault is inappropriate. The mountainous hill areas are also not suitable for physical development due to the presence of topographical, lithological and limiting limitations. Suitable and suitable areas are suitable for 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. Considering the appropriate distance from faults and waterways in suitable topographic areas and mainly on deposits Quaternary is located in the Alluvand plain in the west and east of Kermanshah. Finally, it can be said that the current range of the city of Kermanshah, as well as the surrounding area due to geomorphologic conditions, has severe hazards and limitations an‎d over the past few decades, the physical development of Kermanshah has been made without regard to these restrictions. Therefore, it is suggested that A comprehensive plan for the high risk areas of Kermanshah city has been developed and in the next stage, considering the socio-economic conditions of proposed areas for the development of city physics, is selected.Also due to the constraints of the vertical and massive structures and planning with exact planning in the appropriate areas to be considered.