Istika Nita, Aditya Nugraha Putra, Muhammad Faturrahman, Chairul Umam, Lintang Surya, Novandi Rizky Prasetya, Reni Ustiatik, Yosi Andhika, Sugeng Prijono, Didik Suprayogo, Kurniawan Sigit Wicaksono, Silvia Kohnová, Kamila Hlavčová, Weijun Luo, Liu Yi
River water quality is declining across tropical landscapes undergoing rapid land-use change. We tested whether landform-controlled hydrological pathways explain spatial water-quality patterns in the Southern Malang Plateau (Indonesia). At 28 sites spanning tectonic, karst, alluvial, and volcanic landforms, we computed the National Sanitation Foundation Water Quality Index (NSF-WQI) and applied multivariate analyses. Alluvial rivers were most degraded, with nitrate up to 60 mg L−1, COD >200 mg L−1, and total coliforms up to 175 MPN 100 mL−1, resulting in poor status (WQI <50). In contrast, volcanic catchments dominated by forest and agroforestry maintained good quality (WQI >75), while karst systems showed intermediate but spatially sensitive conditions. Multivariate structure indicates that nutrient enrichment and sediment-associated impairment are regulated by landform-specific erosion–sedimentation and flow-path connectivity rather than land use alone. Integrating landform controls into water governance supports SDG 6 (clean water and sanitation) and nature-based solutions. © 2026 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Department of Soil Science, Faculty of Agriculture, Universitas Brawijaya, Malang, Indonesia; Doctoral Program in Agricultural Science, Faculty of Agriculture, Universitas Brawijaya, Malang, Indonesia; Department of Land and Water Resources Management, Faculty of Civil Engineering, Slovak University of Technology in Bratislava, Bratislava, Slovakia; Agroecotechnology Study Program, Faculty of Agriculture, Universitas Brawijaya, Malang, Indonesia; Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China; Earth, Ocean and Atmospheric Sciences (EOAS) Thrust, Function Hub, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou, China
