The Use of Undimensional Hypsometric Curves in the Evaluation of Erosion and Sedimentation (Case Study: Nachy basin in the Province of Kurdistan)

Physical characteristics such as height and topography of basin; direct and indirect effects are important on erosion process. Soil is one of the most important natural resources of each state, so it is one of the fundamental threats and problems of modern civilized man. In choosing a model for the evolution of the basin, hypsometric curves as a measure considered attending. Hypsometry actual and theoretical undimensional curves, including methods that allows three-dimensional analysis of the area to the user. The placement of these curves to each other, the positions of the sediment and erosion and eventually it becomes clear area. In order to analyze the situation and identify the developmental status of erosion and sedimentation basin with a comparative view, in the Nachy and its sub-basin level, tables and hypsometric undimensional curves are calculated, plotted and compared. Evaluate and analyze the erosion in sub Gagel showed that in the upstream sub-basin, which actual curve is located above the theoretical curve in this part of sub-basin which marker deposition. This process from height of 2100 meters to height of about 1900 meters continues. In the following, the theoretical curve is at the top of actual curves that indicate the status of erosion for this part of the sub-basin. This process continues until height of about 1500 meters which at the height of two curves close together and equilibrium is created. Compare the three sub-basin, Anjiran, Darehvaran and Gagel showed that sub Anjiran, can be placed in rows of basins in relative equilibrium. Gagel sub-basins to equilibrium compared with other more space and we can say that compared to other basins younger. By observing the theoretical and actual curves of the Nachy we realize that the whole catchment basin is somewhat young and relatively low equilibrium.