Estimasi Laju Erosi dan Sedimentasi Daerah Tangkapan Air Waduk Jatigede

Estimation of Erosion and Sedimentation Rates in the Jatigede Reservoir Catchment Area

Abstract

Jatigede Reservoir is a strategic water resources infrastructure in West Java that supports raw water supply, irrigation, hydropower generation, flood control, fisheries, and socio-economic activities. However, the sustainability of these functions is threatened by erosion in the catchment area, which contributes to reservoir sedimentation. The sedimentation rate is estimated at approximately 7.04 mm year^-1 with a volume of ±1.07 million m³, while watershed erosion reaches 5.320 mm year^-1. These processes accelerate reservoir siltation and reduce storage capacity, emphasizing the need for effective watershed management. This study applied the Revised Universal Soil Loss Equation (RUSLE) to estimate soil erosion and the Sediment Delivery Ratio (SDR) to predict sediment yield. The analysis utilized soil type maps, Digital Elevation Model (DEM) data, Sentinel satellite imagery, and monthly rainfall data collected over a ten-year period. A literature review was also conducted to develop practical conservation recommendations. The results showed that erosion in the Jatigede Reservoir catchment area was generally low, with an average rate of 16.703 tons ha^-1 year^-1, and was dominated by very slight to slight erosion classes covering approximately 88.81% of the area. Higher erosion rates were concentrated on steep slopes and areas with limited vegetation cover. The average sediment yield was 3.983 tons ha^-1 year^-1 (SDR = 0.23), equivalent to approximately 786 thousand m³ year^-1. Based on the reservoir's dead storage capacity of 103 million m³, the estimated service life of the reservoir is about 131 years. To reduce erosion and sedimentation, the study recommends the implementation of soil conservation measures to support the long-term sustainability of the reservoir.