The Impact of Geomorphic Variables of Fluvial on Flood Hazard Of Mountain steep Towns (Case Study: Town Torghabeh, Khorasan Razavi province)

The geomorphic units of the fluvial system components are in a way that in many cases geomorphic processes are causing environmental hazards such as floods. In this research Torghabeh city and its basin have been studied for the hazard of a river geomorphic processes. Torghabeh town as a regional and international tourism attraction is 20 kilometers far from the metropolitan city of Mashhad. The output of the upstream catchment basin with regard to the geomorphic variables highly affect the flooding possibility of the city.
In order to conduct the present research, a laboratory analytical method to investigate the behavior of the studied basin, the fluvial geomorphic variables and factors in the flood hazard area, including lithology, elevation, slope, land use, precipitation, vegetation, drainage density, distance from the stream, form factor, slope and soil were selected and included in the research. The layers were required to prepare, prioritize and establish the relationships between these variables and the vulnerability of the Analytic Hierarchy Process (AHP). The Expert Choice software was used to help wit the analysis . Critical flood hazard zones are mainly rural area with densities, recreational areas and resorts, tourist and Network Access Account in Mashhad. It is important to notice that, the man-made factors such as residential and utility violated the privacy of rivers and streams, lack of engineering structures such as bridges over rivers of improper aggravating factor are the most significant variables in the flood hazard area. Leveling and terracing of slopes for construction not only disrupts the balance , but also it has increased the weight of the load of flood intensity. The damages caused by the flood of mass movements within the city limits has been exacerbated in Torghabeh.