Abstract:
The watershed area of the Mangla Reservoir spans across the Himalayan region of India and
Pakistan, primarily consisting of the Jhelum River basin. The area is rugged with highly elevated, hilly
terrain and relatively thin vegetation cover, which significantly increases the river’s sediment output,
especially during the monsoon season, leading to a decline in the reservoir’s storage capacity. This
work assesses the soil erosion risk in the Jhelum River watershed (Azad Jammu and Kashmir (AJ&K),
Pakistan) using the Revised Universal Soil Loss Equation of (RUSLE). The RUSLE components,
including the conservation support or erosion control practice factor (P), soil erodibility factor (K),
slope length and slope steepness factor (LS), rainfall erosivity factor (R), and crop cover factor (C),
were integrated to compute soil erosion. Soil erosion risk and intensity maps were generated by
computing the RUSLE parameters, which were then integrated with physical factors such as terrain
units, elevation, slope, and land uses/cover to examine how these factors affect the spatial patterns
of soil erosion loss. The 2021 rainfall data were utilized to compute the rainfall erosivity factor
(R), and the soil erodibility (K) map was created using the world surface soil map prepared by the
Food and Agriculture Organization (FAO). The slope length and slope steepness factor (LS) were
generated in the highly rough terrain using Shuttle Radar Topography Mission Digital Elevation
Model (SRTM DEM). The analysis revealed that the primary land use in the watershed was cultivated
land, accounting for 27% of the area, and slopes of 30% or higher were present across two-thirds
of the watershed. By multiplying the five variables, the study determined that the annual average
soil loss was 23.47 t ha−1 yr−1
. In areas with dense mixed forest cover, soil erosion rates ranged
from 0.23 t ha−1 yr−1
to 25 t ha−1 yr−1
. The findings indicated that 55.18% of the research area has a
low erosion risk, 18.62% has a medium erosion risk, 13.66% has a high risk, and 11.6% has a very
high erosion risk. The study’s findings will provide guidelines to policy/decision makers for better
management of the Mangla watershed.
