Merri Jayanti, Dyah Marganingrum, Muammar Qadafi, Heru Santoso, Rosmalinda Permatasari, Fikri Hasfita, Mariana Marselina, Herto Dwi Ariesyady, Arwin Sabar
Effective and sustainable water resource management is crucial in monsoon-dominated regions This study examines rainfall variability and its hydrological implications in the Cimanuk-Jatigede watershed, West Java, Indonesia, using a 41-year record (1981–2022) from nine rain gauge stations. The rainfall variability was assessed using the Rainfall Anomaly Index (RAI), seasonal classification was determined by Water Availability Index (WAI) based on the precipitation-to-evapotranspiration ratio, and long-term trends were detected using the Mann–Kendall test and Sen's slope estimator. Results indicate substantial spatiotemporal variability, with annual precipitation ranging from 787 to 6561 mm. Five stations (P1, P3, P6, P7, and P8) exhibited statistically significant increasing rainfall trends (p < 0.05), with the highest rate observed at P7 Pamulihan (Sen's slope ≈ 57.96 mm yr−1). The wet season spans October to May while June to September constitutes the dry season. Direct runoff accounts for approximately 82% of total rainfall, far exceeding infiltration (18%), underscoring the urgent need for adaptive water storage, flood control, and drought mitigation strategies for sustainable watershed management. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2026.
Research Center for Environmental and Clean Technology, National Research and Innovation Agency, KST Samaun Samadikun, Bandung, 40135, Indonesia; Research Center for Climate and Atmosphere, National Research and Innovation Agency, KST Samaun Samadikun, Bandung, 40135, Indonesia; Department of Civil Engineering, Tridinanti University, Jalan Kamboja, Palembang, 30129, Indonesia; Engineering Faculty, Malikusssaleh University, Reuleut, Aceh, Lhoekseumawe, 24300, Indonesia; Department of Environmental Engineering, Faculty of Civil and Environmental Engineering, Institut Teknologi Bandung, Jalan Ganesha, Bandung, 40132, Indonesia; Department of Environmental Engineering, Institut Teknologi Sumatera, Jalan Terusan Ryacudu, Lampung, Way Huwi, 35365, Indonesia