Soil Erosion Assessment on Hill Slopes of Jammu–Srinagar National Highway (NH-44) Using RUSLE Model

Abstract

Soil erosion represents a critical environmental and geotechnical challenge in mountainous regions, particularly along transportation corridors such as the Jammu–Srinagar National Highway (NH-44), which traverses the fragile and tectonically active Himalayan terrain. The combined influence of steep slopes, intense monsoonal rainfall, weak geological formations, and anthropogenic disturbances significantly accelerates erosion and slope instability processes. This study presents a comprehensive assessment of soil erosion along NH-44 using the Revised Universal Soil Loss Equation (RUSLE) integrated with Geographic Information System (GIS), remote sensing, and hydrological modelling. The analysis incorporates key RUSLE parameters, including rainfall erosivity (R), soil erodibility (K), topographic factor (LS), cover management (C), and support practice (P), derived from spatial datasets such as Digital Elevation Models (DEM), land use/land cover (LULC), soil maps, and rainfall records. Runoff estimation was carried out using the Soil Conservation Service Curve Number (SCS-CN) method to evaluate the hydrological contribution to soil erosion. Additionally, geotechnical investigations were conducted to characterise colluvial and alluvial soils, which dominate the study area and exhibit low shear strength and high susceptibility to erosion. The results indicate that soil loss along NH-44 varies from 0.5 to over 40 t/ha/year, with severe erosion concentrated in Ramban, Banihal, Nashri, and Panthyal. A strong correlation between slope gradient, runoff, and erosion was observed, highlighting the dominant influence of topography and rainfall intensity. Slope stability analysis using Bishop’s method yielded Factor of Safety (FOS) values ranging from 1.1 to 1.3, indicating marginally stable slopes that are highly susceptible to failure during intense rainfall events. The findings demonstrate that soil erosion and slope instability are closely interconnected processes and underscore the necessity for integrated mitigation strategies, including bioengineering techniques, structural stabilisation measures, and improved drainage systems. Overall, this study provides a robust framework for sustainable slope management and enhancing infrastructure resilience in Himalayan highway systems.