عنوان مقاله [English]
Due to the complexity of hydraulic and sedimentary problems in rivers, it is not possible to solve the equations analytically, so numerical methods are used. In the present study, the HEC-RAS 5.0.3 model has been used to simulate the sediment flow of the Khondab River. For this purpose, using the topographic map of the route, DEM and TIN of the Shara River route with a scale of 1: 2000, in the HEC-GeoRAS add-on package in ArcMap software, 200 sections along 6 km of the river were prepared. After preparing the cross sections and taking the distances of the left and right shores of the main canal, the relevant information was introduced to introduce the river geometry to the model (HEC-RAS 5.0.3). the flow with a return period of 25, 50 and 100 years was calculated and used for hydraulic simulation of the river. After calibrating the model for the hydraulic conditions of the river and modeling the quasi-volatile flow conditions, the boundary conditions and grain size of the river bed materials were introduced to the model. Using sediment transfer estimation relationships, river sediment transfer capacity was calculated. The results showed that the Mir-Peter and Müller relationship with 26% error is closer to the observed sediment values than the other relationships. Also, the study of erosion and sedimentation status of the river using Houlshtrom and Shields criteria shows that part of the sections of this river is in erosion status and part is being sedimentation.