Assessment of effective indexes for optimal site selection of river material mining, case study: Talvar River in Kurdistan province

In sedimentary rivers, mining of materials regardless of their location, can lead to rapid river displacement, destruction of river banks, arable lands, water structures and consequently makes social and economic problems. The main aim of this study is to recognize and evaluate all the effective parameters in material mining and determination of optimal site selection. In this study, the effective parameters that influence the extraction of river materials in Talvar River of Kurdistan Province have been evaluated using indexes as environmental, geological, geotechnical, hydrologic characteristics, social and economic conditions. For this purpose, Analytical Hierarchy Process (AHP) and Geographic Information System (GIS) are used. The priority of input indexes into the model is obtained using questionnaires from experts related to water and river engineering. The weighting of the parameters is performed afterward using AHP method binary comparison. The GIS technique is then applied to integrate the information layers by overlaying them. Eventually, the maps of optimum and suitable points were extracted for river mining. The morphological results of this study showed that the straight lengths of the river are more sensitive to the variations of bed level compared to meander sections and it is necessary to extract the material in these lengths with same depth and width. According to the results, sediment hydraulic index has the maximum weight due to determination of sediment deposit sites. The results also demonstrated that the first priority of river materials mining came to places that have low longitudinal slopes, placed in bends and are close to access roads.