Assessment of Fluvial Dynamics of Bakiya River, Central Nepal Using Stream Classification

Using the Rosgen Stream Classification System (RSCS), this study investigates the hydrological features and fluvial morphology of the Bakiya River, a seventh-order stream that traverses the Siwalik and Indo-Gangetic plains of Central Nepal. An extensive assessment of morpho-hydraulic parameters and sediment size distribution across 17 transects was made by a combination of field surveys and GIS-based analyses. The majority of the transects were classified as C4 streams, which are distinguished by meandering channels that are gravel-dominated, slightly entrenched, and connected to floodplains. The stream types B4, F4, and E4 have also been identified, which all display unique hydrological and geomorphic characteristics. The study found that human activity sediment deposition and tributary inputs all affected downstream changes in channel morphology. Vegetation played a crucial role in stabilizing streambanks, and areas with higher erosion susceptibility and entrenchment were identified as priority zones for engineered interventions. The research enhances our understanding of river stability and provides useful guidance for sustainable watershed management and restoration by combining Rosgen classification principles with localized geomorphic and anthropogenic features.