The Benanga Dam in the Lempake Village, North Samarinda, East Kalimantan, is a vital infrastructure that controls and stores water flow. In the last four years, there has been an increase in the reservoir volume by 111,941 m3, attributed to sedimentation dredging activities in 2021 by the Ministry of Public Works and Public Housing. Sedimentation, triggered by human activities such as illegal mining and deforestation upstream of the dam, has led to a reduction in the reservoir capacity from 1.6 million m3 to 500,000 m3. This sedimentation has resulted in significant impacts, including floods in the Karang Mumus River Basin. Analysis of the Dam Capacity Curve indicates sedimentation of approximately 27,985 m3 per year, with a projection of silting up to the normal water level at +7.2 m in 7–8 years. Effective mitigation measures are essential to maintain the function and capacity of the Benanga Dam. Regular contour measurements and dredging according to sedimentation rates are crucial steps to ensure the sustainability of this infrastructure and manage the flood risk in the surrounding area.