Spatio-temporal analysis of abrasion susceptibility effect on land cover in the coastal area of Bantul regency, Yogyakarta, Indonesia

Abstract

Shoreline dynamics naturally occur in coastal areas, and over time, are also influenced by anthropogenic processes taking place both on-site and upstream. Bordering the Indian Ocean, the coastal area of Bantul Regency in the Special Region of Yogyakarta is faced with typical strong and high waves that induce changes in its shoreline dynamics and activities. Consequently, tourism, a leading economic sector in the area, often needs to adjust to such changes. Here, shorelines were extracted from the spatial data of time-series Sentinel 2A imagery (2015, 2016, 2017, 2018, 2019, and 2020) using water index transformation, MNDWI, while the land cover changes were analyzed using the Decision Tree classification. Based on the results, accretion appeared most significant from 2016 to 2017, creating an additional 22.32 ha. In contrast, shoreline change from 2019 until 2020 indicated the most severe abrasion that led to a loss of 34.89 ha. The highest rate of landward shoreline change was 41.58 m/year.