Land Cover Dynamics and Multitemporal Erosion-sedimentation Modelling of the Rejoso Watershed for Sustainable Management
Fernanda Azmi Hariyadi *
Department of Water Resources Management, Magister Program, University of Jember, Jawa Timur, Indonesia.
Bambang Hermiyanto
Department of Soil Sciences, Faculty of Agricultural, University of Jember, Jawa Timur, Indonesia.
Subhan Arif Budiman
Department of Soil Sciences, Faculty of Agricultural, University of Jember, Jawa Timur, Indonesia.
Idah Andriyani
Department of Agricultural Engineering, Faculty of Agricultural Technology, University of Jember, Jawa Timur, Indonesia.
Luh Putu Suciati
Department of Agribusiness, Faculty of Agricultural, University of Jember, Jawa Timur, Indonesia.
*Author to whom correspondence should be addressed.
Abstract
The Rejoso Watershed in Pasuruan Regency, East Java, has experienced land-cover degradation associated with forest loss, expansion of built-up areas and increasing pressure on watershed functions. This study assessed land use/cover change from 2017 to 2024 and linked the observed dynamics with erosion and sedimentation patterns to support sustainable watershed management. Sentinel-2 land-cover data for 2017, 2020 and 2024 were analysed using multitemporal LUCC assessment, supported by non-parametric statistical verification through the Friedman test, Kendall’s W and Wilcoxon signed-rank tests. Potential erosion and sediment yield were estimated using USLE, MUSLE and the Sediment Delivery Ratio at the land mapping unit level. The results showed that forest cover declined by 2,721.64 ha during the study period, with the sharpest decrease occurring between 2020 and 2024. Built-up land expanded consistently, indicating continued conversion pressure. The statistical tests confirmed significant forest decline and built-up land expansion across the watershed. Erosion modelling identified SPL 20 in Tosari as the main potential erosion hotspot, whereas SPL 11 in Nguling produced the highest sediment yield across all periods. Although total sediment yield declined from 276,026 tonnes/year in 2017 to 189,256 tonnes/year in 2024, the reduction was mainly associated with lower rainfall erosivity rather than improved land cover conditions. These findings provide a spatial basis for prioritising conservation and watershed rehabilitation.
Keywords: Rejoso Watershed, land cover change, Sentinel-2, USLE, MUSLE, sediment yield, rainfall erosivity, erosion hotspot, Sediment Delivery Ratio, sustainable watershed management