Effect of gabion dam construction on peak discharge and hydraulic characteristics of river flow

Erosion and sediment transport is an important river phenomenon and is very important for river engineering and management projects. The morphological changes that occur due to the construction of cross structures in the flow path are the response of the river to establishing a balance between erosion and sedimentation. Therefore, the reaction of the river should be evaluated before any structure is built along the river. In the current study, the hydraulic conditions of the river in a 5 km long path from the Kabudkamer River in Zarand Saveh in Central Province before and after the construction of hydraulic structures in the flow path were modeled using the geometric data of 200 cross sections in the HEC-RAS software. Hydraulic parameters such as water level, water surface width, flow velocity, bed shear stress, Froude number, hydraulic depth, and velocity were evaluated before and after device construction. The results showed that in the case of creating a structure and obstruction, the flow speed decreases as the flow approaches the dam, while after passing over the dam, the flow speed increases. Therefore, in this case, the erosion will increase after the overpass. In the absence of a barrier, the flow speed was almost constant before reaching the section with an overpass in the blocked state, but after passing this section, the flow speed increased. The construction of gabion dams in river basins has reduced the peak flow of floods with different return periods. As the return period increases, their effect on the reduction and control of floods decreases.