Lintang Suska Hariwati, Anthon Efani, Fitri Candra Wardana, Muhammad Fathur Rouf Hasan
The Brantas River Basin accounts for roughly 25% of East Java's watershed area and is facing increasing environmental pressure driven by land use and land cover (LULC) changes, particularly in the upstream region. Alterations within riparian zones can strongly influence surface water quality, yet spatio-temporal assessments using Euclidean distance–based approaches remain limited. This study examines the relationship between LULC dynamics and surface water quality in the upstream Brantas Basin from 2020 to 2025. Water quality data were collected from three monitoring stations during wet and dry seasons, covering eight physical, chemical, and biological parameters. LULC classification was generated from ESRI Sentinel-2 imagery and processed using Geographic Information Systems. Descriptive statistics, correlation analysis, and principal component analysis (PCA) were applied to assess spatial–temporal patterns and identify parameters most sensitive to land-use changes. Results show that the upstream sub-watershed consists of four dominant LULC classes: built-up areas, croplands, forested areas with vegetation > 15 m, and water bodies. Between 2020 and 2025, built-up areas and croplands expanded by 3.4% and 3.2%, while forested areas declined by 7.4%. Despite several parameters meeting regulatory thresholds, water quality degradation was indicated by increasing concentrations of chemical oxygen demand (COD), total suspended solids (TSS), and fecal coliform. Spearman correlation analysis reveals that built-up riparian areas are the dominant LULC factor influencing water quality, exhibiting strong to very strong correlations with TSS (ρ = −0.131 to 0.953) and COD (ρ = −0.393 to 0.926) across monitoring stations. These results show that stricter riparian protection and land-use control are needed, especially in growing cities, to effectively reduce sediment and organic pollution in the upstream Brantas Basin. Copyright: ©2026 The authors.
Department of Environmental Resources Management and Development, Universitas Brawijaya, Malang, 65145, Indonesia; East Java Provincial Environmental Agency, Surabaya, 60234, Indonesia; Faculty of Fisheries and Marine Science, Universitas Brawijaya, Malang, 65145, Indonesia
