Land Use Change and Soil Conservation Services Curve Number (SCS-CN) in Karangmumus Watershed Samarinda

Land use changes significantly impact hydrological processes and flood risk. This study investigated land use changes and their effect on the Soil Conservation Services Curve Number (SCS-CN) in the Karangmumus Watershed, Samarinda, Indonesia. Land use data from the Ministry of Environment and Forestry, spanning 1990-2020, revealed a decline in secondary dryland forest area by 26.2 km² and expansion of mining activities by 13.7 km². These changes significantly altered the SCS-CN, increasing from 70.39 in 1990 to 77.48 in 2020. A strong linear relationship between SCS-CN and peak discharge (R² = 0.996) was observed, indicating that every unit increase in SCS-CN resulted in a 1,6842 m3/second increase in peak discharge. This highlights the critical role of land use management in mitigating flood risk in the Karangmumus Watershed. The study emphasizes the need for strategies such as land rehabilitation, afforestation, and effective drainage systems to address the increasing runoff potential and mitigate flood risk in this region.