Year: 2025 | Month: June | Volume: 12 | Issue: 6 | Pages: 675-690
DOI: https://doi.org/10.52403/ijrr.20250677
Assessment of Erosion Hazard Levels in the Watershed Rehabilitation Area of PT Arutmin Indonesia, Bunglai V Block, Riam Kanan Sub-Watershed, South Kalimantan
Eko Nor Hardanto1, Muhammad Ruslan1, Kissinger1
1Master of Forestry Program, Faculty of Forestry, Lambung Mangkurat University, Banjarbaru, South Kalimantan, Indonesia
Corresponding Author: Eko Nor Hardanto
ABSTRACT
Soil erosion represents a critical issue in the forestry sector due to its detrimental effects on water quality and the sustainability of rehabilitation activities. This concern becomes particularly urgent in upstream watershed areas, where erosion can trigger cascading negative impacts throughout the entire watershed system. This study aims to estimate the erosion hazard class (EHC) and level of erosion hazard occurring in rehabilitated watershed areas, specifically in the Riam Kanan sub-watersheds located in Bunglai V Village. The Universal Soil Loss Equation (USLE) method was applied to estimate erosion hazard, taking into account additional influencing factors such as slope class, land cover type, rainfall intensity, and soil solum depth. The study was conducted in Bunglai V Block, which is divided into two sections: the Upper Road Block (Block A, comprising three land units) and the Lower Road Block (Block B, comprising four land units). The results indicate that Block A contains three distinct EHC: Light (I-L) with an erosion rate of 48.45 tons/ha/year, Moderate (II-M) with 165.18 tons/ha/year, and Heavy (III-H) with 122.25 tons/ha/year. Similarly, Block B also exhibits three classes: Light (I-L) at 61.71 tons/ha/year, Moderate (II-M) at 145.34 tons/ha/year, and Heavy (III-H) at 86.21 tons/ha/year. The erosion hazard levels were influenced by soil solum depth, where severe hazard areas (III-H) had shallower solum compared to areas with light and moderate hazard levels, indicating higher erosion risks in shallow soils. Based on these findings, several management strategies are recommended, including maintaining land cover as plantation forest, constructing ridge terraces, and planting along contour lines. In areas with gentle slopes, understory vegetation should be established using an agroforestry system, while areas with moderately steep to steep slopes should utilize cover crops, which help stabilize the soil through their extensive root systems and reduce erosion impact.
Keywords: Erosion Hazard Level, erosion control strategies, soil erosion, USLE method, watershed rehabilitation
[PDF Full Text]