Assessing the Association between ENSO, IOD, and Streamflow Variability in the Lower Batanghari River Basin, Sumatra, Indonesia

Linda Handayani (Doctoral Program in Earth Science, Faculty of Earth Science and Technology, Institut Teknologi Bandung, Jalan Ganesa No. 10, Bandung, 40132, West Java Physics Study Program, Faculty of Science and Technology, University of Jambi, Jalan Jambi - Ma Bu)
Munajat Nursaputra (Doctoral Program in Earth Science, Faculty of Earth Science and Technology, Institut Teknologi Bandung, Jalan Ganesa No. 10, Bandung, 40132, West Java Laboratory of Forestry Planning and Information System, Faculty of Forestry, Hasanuddin University)
Rustan (Physics Study Program, Faculty of Science and Technology, University of Jambi, Jalan Jambi - Ma Bulian KM. 15 Muaro Jambi, 36361, Provinsi Jambi Doctoral Program in Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Ja)
Nanang T. Puspito (Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Jalan Ganesa No. 10, Bandung, 40132, West Java.)
Rusmawan Suwarman (Atmospheric Sciences Research Group, Faculty of Earth Science and Technology, Institut Teknologi Bandung, Jalan Ga-nesa No. 10, Bandung, 40132, West Java.)

Forum Geografi
Vol. 41 No. 1 (2027): April 2027

This study examines the relationship between the El Niño–Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD) and seasonal streamflow variability. Streamflow was simulated using the Soil and Water Assessment Tool Plus (SWAT+) during two specific land-use periods (2000 and 2023), integrating topographic, soil, land-use and climate data, and evaluated at three lower stations: Muara Kilis, Sungai Duren and Simpang Berbak. Pearson and partial correlation analyses were used to assess antecedent June-July-August (JJA) and concurrent September-October-November (SON) climate conditions against September-November (SON) streamflow. Both ENSO and IOD showed consistently negative relationships with SON streamflow. The results reveal distinct seasonal patterns: JJA conditions showed clearer ENSO-streamflow relationships, whereas during SON, the IOD-streamflow relationships became more pronounced, with correlation reaching -0.64 at Muara Kilis. Partial correlation showed that the associations remained significant after accounting for the other climate index, although their magnitudes varied in the JJA-SON and SON-SON relationships. These findings demonstrate seasonal and spatial variability in climate-streamflow relationships across the lower Batanghari River Basin.