عنوان مقاله [English]
Qorveh, one of the cities of Kordestan province, has high amount of precipitation and, consequently, a significant resource of water. Geological surveys, physiography and hydrology, and in particular field studies, have revealed rivers' significant role and influence on the formation of human activities and settlements. Unfortunately, much of the locally carried out planning has ignored hydro-geomorphological factors. In addition, population growth and the growth in residential and industrial areas have caused uneven progress of the residential areas towards the riverside which has, consequently, changed the natural shape of the river such as its width, length, slope, sediment, and the like. These problems shows the importance and necessity of thorough hydro-geomorphological studies. Therefore, the main objective of this study was to investigate the hydro-geomorphological status of the Shoor River's basin and evaluate the its lands' capabilities to develop urban areas, determine the optimum location based on hydro-geomorphological criteria, minimize the undesirable impacts of inhabitants of cities and villages on the highlands, especially the catchment areas, and minimize the harmful effects of the environmental hazards on agricultural products and inhabitants.
Materials and methods
The study is based on field, library, and software methods. Firstly, using the topographic maps, the study area of the basin was specified. In this study, 8 factors of lithology, faults, slope, aspect, elevation, distance from the river, vegetation, and land use were used in order to evaluate and zone suitable areas for urban development of Qorveh. After the preparation of the information layers, the coefficients and their values were estimated by the use of ANP model. In this model, like AHP, the measurement of the amount of the relative importance is done by pairwise comparisons with the help of the range of 1 to 9. Number 1 represents the equal importance of two factors and 9 represents the extreme importance of one factor over the other. To this end, for each model, a total of 15 questionnaires were distributed among specialists (5 Land use planning, 5 urban planning, and 5 geomorphology specialists) to rate each of the factors. After analyzing the questionnaires, to calculate the final weights of each criteria and subcriteria (according to the internal relations), Super Decisions software was used for the ANP model. Then, indicators and variables affecting urban development, using the Fuzzy function, were sub-Fuzzed and all layers of the study were standardized and compared. The coefficients were transmitted to the GIS polygonal descriptive databases to make them more quantitative and comparable. Finally, the final maps were made by overlaying the information layers maps.
Discussion and results
In the present study, to locate suitable areas for urban development, 8 factors were used and the classification was done. On this basis, the suitable areas for future development of the city have a slope of less than 11 %, the lithology persistent for building, low elevation, barren land use, and the changeable vegetation. In addition, they are distant from the fault lines and they are near the riverside. Additionally, the map of each criteria was prepared and the final map was obtained by combining the information layers, based on the weight obtained through ANP.
The ANP Model, because of having features such as simplicity, flexibility, simultaneous use of qualitative and quantitative criteria and final ranking of the options, can provide a suitable framework for analyzing the issue and determining the final ranking of the options.
However, since allocating evaluation weights cannot provide enough reliability, the use of fuzzy logic, for more integration between layers and fixing possible errors, is needed. Finally, the study area was divided into five regions in terms of available potential and the ability for the purposes of the urban development. According to the criteria which was considered in this zoning, it can be said that, areas with the highest score, are located in ideal areas and away from danger.
However, it should be noted that the significant presence of the geomorphologic phenomena, such as Bader and Parishan mounts in the southern parts of the study area, as well as the existence of faults in the southwest and southeast of the area have caused the basin to be in a very inappropriate class in relation to the development of the space. The results of this study indicate that the Shoor River's basin has a high potential for spatial development and urban planning in the future.