Analyzing Environmental Abilities for Urban Development(Case Study: Ilam City)

IntroductionIn present century, the tendency to urbanization has been seen in most countries. The physical development and population growth of Iran cities have had a coordinated and balanced increase until several decades ago. Based on new changes, the cities have been changed and improved quickly. These changes have been unbalanced and uncoordinated in the form of quick increase of population and physical growth of the cities. Generally, this urban unbalanced development has been happened in the unprepared lands in the cities. Therefore, the most important issue against urban development is the place for their future development. Principally, the establishment and creation of a city is depended on the geographical location and condition more than anything else. Based on geographical site where the cities are located on it, they may encounter with different geomorphologic phenomena for their future development. These phenomena may provide the possibility of developing city or they may be expressed as an impasse in urban development and reconstruction. How much cities are developed they will encounter more with different unites of topography and geomorphology and their related issues. Therefore, the importance and necessity of knowing the features of natural environment for recognizing proper points for creating buildings and structures will be obvious from improper points. Urban Spatial and growth development in Ilam have been affected somehow by factors such as imposed war, urban-rural immigration like borderline villages and cities. Despite the end of war, Ilam has an extraneous growth consecutively because of starting noticeable and extensive hostilities and the significant role of Ilam and its official-political center and services. The population increase has caused the frequent demands for residences and according to the limitation of area in Ilam, we can see the construction on the hills and Slopes over 15%. The natural condition around the city does not have an appropriate base for development because of environmental situation. So, according to mentioned problem, it is necessary that the urban development to be ordered for preventing the destruction of proper usages that one solution is optimized location of urban development.
MethodologyThe method of the research is applied method based on purpose and is descriptive-analysis based on the identity. The method of gathering information is limited to case study based on field-library studies and Spatial data of studied scope. The Spatial information (Slope, Slope aspect, topography, land use, geology, distance from water channel and road) is digitalized and save from related maps. The model which is used to incorporate the mentioned information is actually a weighted model that criteria are located in a hierarchy system and compared pair-wise and each of them is given an especial weight between scale 1 to 9. Based on AHP model, weight and priority of parameters are performed based on physical features and characteristics of the scope according to expert's views.
Results and discussionIn this section of the article, the effective variables and evaluation of affect proportion in each of them in determining the optimized direction of urban development are studies and evaluated in Ilam. Besides the analyzing the percentage of each factor affect, a map is provided for developing according to each layer and then a final map is provided and presented for urban development. In the final layer, the criterion with more value has more priority than other criteria. The coefficient of slope criteria, hypsometry, lithology, land use, the distance from road, geographical direction and distance from water channel are 0/33, 0/22, 0/16, 0/11, 0/08, 0/06 and 0/04 respectively. The observations show that the topography has a great effect on location and urban space development. Because this city is located by mountains from all directions and based on dip, Ilam is located in a dip between 0% and 15% and the higher slopes are coincided on mountains. Also, the material of geology in the studied scope is lime, marl, shale and alluvial components that subsidence of the city is not unexpected by urban development on these components.
Conclusion The urban Spatial development means evasive and expanding physical areas of a city is one of the necessities for developing urbanization and it should be guided to a direction to observe all principals of development. Understanding urban development has an important role in planning urban development and balanced urban development management. Studying and recognizing the natural features in every region can play an important role in planning and proper location for urban development. However, the expanse of the city without paying attention to natural features can develop the city toward a direction that its results would be the increase of prices, problems for services and encountering with some environmental dangers. So due to natural factors, geographical and environmental Therefore, these factors were the substrate and position of Main City In addition, it can all urban design elements such as space, form, structure and texture of change It is important.
Ilam is located inside of a field among mountains where is surrounded by mountains that is in contract with gemological conditions by urban area development toward mountains for the lack of enough land in the filed for its expanse. Due to the natural characteristics of the study area, by providing different information layers, logging and analysis of geographic information system database,by using AHP model, The land proportion is divided to five areas most inappropriate (25,3%), inappropriate (31,7%), average (18,5%), appropriate (14,6%), most appropriate (9,9%). Based on less area of appropriate and most appropriate areas for Ilam development than inappropriate areas, it is possible to revise proper strategies for developing the center of residences and guide the function toward appropriate areas and prevent the evasive of residences in the inappropriate areas and in addition to protecting this part environment, the existed sources can be used desirably.