عنوان مقاله [English]
Assessment and Prediction of the process of expansion of residential areas with Geomorphological Approach and Environmental Management (Case Study: Paveh City)
Cities are always affected by various factors and expansions. As cities expand, their coming across various topographic units increase. Therefore the importance of knowing the characteristics of the natural environment, in order to identify suitable zones for the construction of buildings, is identified. Urbanization leads to widespread land use and adverse environmental impacts. In some cases, the expansion of urban spaces also results in environmental hazards and threats to human societies. Geomorphological studies are needed to identify most of the characteristics of the natural environment. Through this awareness, it is more feasible to take effective steps in choosing the most suitable place to create and expand cities and it's possible to lower the risk of natural processes and to counteract them. The present study, thus, attempts to use the LCM model with a geomorphological approach, evaluate the evolution of Paveh settlements during 1998 to 2013 and predict the future development of these areas by 2030. The purpose of this approach is to plan and organize the movement of the settlements towards the less risky areas.
To predict the expansion of residential areas with a geomorphological approach and environmental management, the following steps are taken. Initially, satellite imagery of 1998 and 2013 was produced. The next step was to pre-process the images where the data were examined for geometrical and radiometric errors. After preprocessing the images, the land use map of the area was prepared using a supervised classification method. Teaching examples are defined in 5 classes of agriculture, gardens, rangelands, residential areas, as well as unoccupied lands. By designing training samples using the maximum likelihood method, land use maps of the study area for 1998 and 2013 were prepared. The next step was to detect changes using LCM which was modeled in four stages. Initially, the changes in 1998 and 2013 were examined. Then using the MLP method, transition potential maps were prepared. Then, land use change forecasts were prepared for 2030. Finally, the predicted LCM map was compared with the existing reality map. The results indicate the acceptable accuracy of the prepared maps.
The city of Pave, located on the high Zagros zone and along the northwest - southeast, has shown the characteristics of the Zagros Mountains well. The geomorphological study of Paveh and its surroundings indicates the existence of a mountainous geomorphologic unit with active slopes as well as valley systems with active river systems as well as an active fault system at its surface. A combination of the above factors indicates that one of the most important challenges of Paveh city is limitation of topography and lack of suitable land for urban expansion. The land use map of the study area in 1998 showed that 4.2 km2 of the entire area had been residential areas. It is estimated that the settlement area of Paveh has reached 6/5 km2 in 2013. Spatio-temporal comparison of Paveh city expansion trend shows an increase of 2.5 km2 in this period and these results indicate significant spatial variability and consequently greater interference with geomorphological units. The estimated future expansion based on the LCM model for 2030 was 10 km2. The results showed that the transverse as well as longitudinal expansion of Paveh would be significant in 2030. This expansion of the settlement often corresponds to sensitive areas and this results in increased processes and increased risk levels.
The results showed that the expansion of residential areas has been increasing rapidly, reaching from about 4.4 km2 in 1998 to about 10 km2 in 2030. According to the maps prepared and the available information, Gardens and agricultural lands reduced as residential areas expanded. Surveys showed that the existing urban area in 2013 had a transverse and longitudinal expansion compared to 1998. This process, based on the forecast for 2030, will also occur at a much broader level than 2013. The topographical position and the increasing trend of population over the period under consideration have led to the development of residential areas, moving to more risky areas and increasing the risk factor. In other words, based on the geomorphological status of the area and morphological forms, the expansion of urban areas to high risk areas occurs. This study showed that despite the efficiency of this research as a precursor, the necessity of preparing a geomorphological urban plan with form and process approach is essential for Paveh and other Iranian cities.