Identification of susceptible areas for the development of agricultural lands based on parameters Hydro geomorphology(Case study: Sanandaj city)

Today, geomorphic studies are considered as the base of studies on natural resources. Recognizing the processes and active mechanisms on these landforms and their characteristics, as well as understanding the type of use of these units in using the natural environment and sustainable development is important. Many of Iranian towns and villages are on plains and alluvialfans and as a result, exploitation of the plains has become diverse and growing; but there are problems and limitations in the use of these areas. For a successful farming, consideration of climatic and environmental conditions is of tremendous importance. Therefore, the designation of geomorphic units is a suitable method for detailed studies of natural resources planning and management and environmental hazards. According to some experts, the assessment of environmental power is an instrument for identifying a land for activities such as agriculture and forestry (Quang minh et al, 2003). The agricultural sector of Sanandaj Province is especially important among the economic sectors of the province since in terms of production and employment, it is ranked second after the services sector. The geographical and climatic conditions and abundant water resources provide the potential benefits of agricultural production in the city. In  recent years, with the adoption of new software and hardware methods, many efforts have been made to determine the capability and management of land leading to fruitful results.

The purpose of this study is to assess land suitability for agricultural activities in Sanandaj based on hydrogeomorphological parameters. To this end, the research method is based on descriptive-analytic methods. Research data includes statistical information (information on the status of groundwater and climate parameters), information layers, information extracted from satellite imagery (land use), as well as library information. Software used in the research includes ARCGIS (providing information layers, fuzzy, final output), IDRISI (implementation of the OWA model), Google Earth (validation of results), and SuperDecisione (weighting to criteria). The data layers of this research are soil, land type, geology, slope, altitude, precipitation, river, temperature, groundwater status, and groundwater chemical quality. Since the value and importance of the parameters are not the same for the desired purposes, the parameters were evaluated using expert opinion (5 geomorphic experts) by the ANP method and fuzzy by using the fuzzy function in ArcGIS software. Afterwards, standardized layers are entered into the IDRISI software and then combined with the ANP model using the OWA model based on the obtained values. Finally, the final map is made. After drawing up the final map to verify the results, 50 random samples were used to validate the result.

In this research, ten parameters have been used for the development of agricultural lands in Sanandaj. The parameters are assigned in three clusters: Geomorphologic parameters (elevation, slope and geomorphology units), hydroclamite (river, underground water, chemical water quality, temperature and precipitation), and land cover (soil and lithology). In this research, after providing information layers, these layers are standardized using ARCGIS software. The  geomorphological parameters are standardized in such a way that the altitude, the lower height means that the pixel is worth more And also in terms of slope, areas with a lower slope are worth more. In terms of geomorphology units, the lake and mountain units are of the lowest value. In terms of hydro-climatic parameters, regions with higher rainfall and temperatures near the river have lower groundwater depths and areas with lower EC values ​​are of higher value. In addition, the areas with inspetisol are of higher value and lithologically, the areas with alluvial lithology are more valuable. The value of the criteria was then calculated using the ANP model. Finally, the obtained value was applied to the layers and in the end, using the OWA model, the final map is obtained.

Since agriculture makes a major contribution to the economy of Sanandaj, and given the great potential of the city in terms of water resources, it is necessary to make proper planning and location in this area. In the present study, according to studies conducted and hydrogeomorphological survey related to the study area regarding zoning the area for the development of agricultural lands, it has been attempted to identify suitable areas for the desired purposes. The results of zoning using integrated network analysis and sequential weighted averaging model have been verified using integrated network analysis model and random sampling method is verified. The confirmed results indicate that the final map has 86 percent accuracy. The results of the present study indicate that the major part of Sanandaj does not have the proper level of agricultural activities so 1587 km2 of the city area is in the inappropriate class and the relatively suitable and suitable class area is 801 and 579 square kilometers, respectively. According to the results, about 53% of Sanandaj area is not suitable for agricultural activities, especially for water crops.