Optimization of Culvert Dimensions Using HEC-RAS on River Mutha: A Hydro-Environmental Approach

This study examines the effects on hydraulics and the environment of installing zigzag culverts spaced 500 meters apart along a modified river channel. Optimizing culvert dimensions to improve water quality and efficiently regulate flow is the main goal. Hydraulic performance and flow behavior are assessed using a combination of HEC-RAS simulations and physical modeling with a distorted Froude scale (built in ferrocrete). The best culvert size, according to simulation results, is 15.5 m × 1.0 m. This size successfully eliminates overtopping threats by providing the lowest upstream water surface height (1.8 m) and a positive freeboard of 0.2 m. The physical model's experimental results validated the numerical results by confirming a 37.25% (prototype) and 38.09% (model) decrease in Velocity. Monitoring of the water quality before and after the installation of the Culvert showed notable improvements: the pH rose by 6.79 %, the dissolved oxygen improved by 64.68 %, and the Total suspended particles reduced by 79.63%. These findings demonstrate that the suggested culvert design improves environmental conditions by reducing silt, increasing aeration, and increasing hydraulic efficiency. A sustainable method for managing river flow and enhancing water quality is shown by the integrated modeling technique.