Estimation of useful life of the Logung Reservoir using universal soil loss equation

Sedimentation significantly influences the operational lifespan and effectiveness of reservoirs, particularly in terms of their ability to supply irrigation and manage water resources. The Logung Reservoir in Central Java, Indonesia, experiences continual sediment deposition driven by erosion within its catchment area. This study estimates the reservoir’s remaining useful life by combining erosion-based sediment yield modeling with empirical bathymetric data. The potential sedimentation rate was calculated using the universal soil loss equation (USLE), modified by the sediment delivery ratio (SDR) and trap efficiency (TE), resulting in a projected annual sediment volume of 158,945.2 m³. Conversely, actual sediment accumulation derived from dead storage volume changes over five years was significantly higher at 4,818,622.4 m³ per year. This discrepancy suggests that erosion-based models may underestimate sediment input when conservation measures are not fully accounted for, whereas field measurements provide a more accurate reflection of sediment dynamics. Based on these findings, the estimated remaining useful life of the Logung Reservoir is between 15 years based on the actual sedimentation rate and 30.3 years based on the potential sedimentation rate. These results highlight the urgent need for improved catchment area management and sediment mitigation efforts to ensure the long-term functionality of the reservoir beyond its original design lifespan. © 2025, Polskie Towarzystwo Inzynierii Ekologicznej (PTIE). All rights reserved.