Spatial analysis of LULC change and DEM-derived hydrological characteristics in a tropical micro-watershed (Lubuk Yu, Malaysia)

Abstract

Land use and land cover (LULC) change plays important role in influencing hydrological characteristics, especially in watersheds that are sensitive to both natural variability and anthropogenic disturbance. This study focuses on spatiotemporal LULC dynamics and examines terrain-derived hydrological characteristics in the Lubuk Yu watershed, Pahang, Malaysia (4.12 km²), using Geographic Information Systems (GIS) and remote sensing techniques. Multi-temporal Landsat 8 Operational Land Imager (OLI) imagery from 2016 and 2023 was classified using a supervised maximum likelihood approach into three dominant land cover classes: vegetation, water bodies, and barren land. The results indicate that vegetation cover decreased from 3.10 km² (75%) in 2016 to 2.80 km² (68%) in 2023, while water bodies increased from 0.78 km² (19%) to 1.01 km² (24%), and barren land increased from 0.24 km² (6%) to 0.29 km² (7%). Classification accuracy achieved 86.67% (Kappa = 0.77) for 2016 and 83.33% (Kappa = 0.74) for 2023, indicating substantial agreement with reference data. Hydrological characteristics derived from the Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) include watershed delineation, flow direction, flow accumulation, and stream ordering. Morphometric analysis indicates a drainage density of 28.64 km km⁻² and stream frequency of 29.78 streams km⁻², reflecting a dense and responsive headwater drainage system dominated by first-order streams (62 channels) with a total stream length of 68.34 km. Spatial overlay analysis reveals that areas experiencing vegetation reduction are frequently associated with zones of higher flow accumulation, particularly along tributary corridors, suggesting increased potential for runoff concentration. This study provides a process-oriented interpretation of how moderate land-cover changes in a tropical micro-watershed can be linked to terrain-controlled hydrological behaviour. The findings offer baseline insights to support watershed management, land-use planning, and environmental monitoring in Lubuk Yu and similar tropical catchments.