Rivers are the main and easily available source of water for various uses, and one of the main aims of river engineering is to control sedimentation and erosion. Due to strategic and environmental circumstances, the Kabul River is a well-known river in Afghanistan that attracts much interest for its water project design, existing reservoirs, and water supply to towns and industrial units. The Kabul river carries and delivers the highest sediment loads among the rivers of Afghanistan, and river sedimentation is a serious problem in Kabul city. The HEC-RAS (Hydrologic Engineering Centre River Analysis System) model is used to evaluate the hydrological parameters and sedimentation processes for variations in transverse and longitudinal profile, velocity and shear stress fluctuation, mass change, bed level change, total sediment, erosion, and deposition problems in a 40-KM section of the Kabul River in Kabul Province, from Pul-i-Surkh station of Maidan Province to Tangi-Gharo station of Kabul City. Some branch rivers and streams have joined from two sides along this river, which increases the sediment. More sedimentation is caused by population growth, nonstandard construction around the river, and the desire for a sanitation system in Kabul City. And also, having a low and variable slope in the middle length of this river causes more sediment problems. The study period for this research was from January 2016 to June 2020. A useful pattern of the conditions in Kabul City and the impacts of sediment transport, erosion, and sedimentation processes can be the output of this study.