Mapping shoreline changes using Landsat Imagery at Pemalang, Central Java Province, Indonesia

Department of Marine Science and Technology, Faculty of Fisheries and Marine Sciences, IPB University, Dramaga, Bogor 16680, West Java, Indonesia

^* Corresponding author: jppanjaitan@apps.ipb.ac.id

Abstract

Pemalang Regency possess sloping geographical with shallow waters, it’s potential to increase the area for pond fisheries and coastal tourism. This utilization causes changes in the coastline, which influenced by mankind and natural factors. The study aims to map shoreline changes in Pemalang, Central Java from year 2007-2022 using imagery of Landsat 7 ETM+ and Landsat 8 OLI/TIRS. The Digital Shoreline Analysis System (DSAS) method was performed to calculate rate of change statistics for a time series of shoreline vector data. This method uses parameters, including baselines, shorelines, and transects. The DSAS results in the year 2007-2022 shoreline change (NSM) and the 15-year mean shoreline change (EPR). All subzones occurred abrasion. Subzone D2 occurred greatest abrasion (- 442.43 m). Subzones undergoing accretion include A1, A3, B1, B3, C2, C3, D1, D2, E2, and E3. The largest accretion occurs in A3 (333.05 m). Pemalang Beach in the year 2007-2022 occurred a change in coastline dominated by abrasion. The largest abrasion is in A3 (-2.39 m/year) and the smallest is in A2 (-1.89 m/year). The abrasion factors are the sloping beach, land use as tourist area, mangroves that are not maintained, and the flooding in May 2022. The changes in the coastline that have occurred are severe up to very severe.