Evaluation of shoreline change using multitemporal satellite images

Coastal areas are vulnerable to change because, in this region, many human activities and natural influences change. These activities can result in changes in the existing coastline. Moreover, the city of Surabaya has a reasonably long coastline. This study calculated the speed of shoreline change using remote sensing technology of SPOT 6 and SPOT 7 high- resolution satellite imagery from 2015 to 2019. Calculation of shoreline change speed is assisted by the application of the Digital Shoreline Analysis System (DSAS) using several methods, namely Shoreline Change Envelope (SCE), Net Shoreline Movement (NSM), End Point Rate (EPR), and Linear Regression Rate (LRR). Based on data processing and analysis, the longest coastline of Surabaya City was found in 2015 with a length of 69.605 km, and the shortest coastline was in 2019 with a length of 65.759 km. The maximum speed of Surabaya shoreline changes can be identified by using the SCE method (956.590 m), the NSM method (+584.722 m), the EPR (+148.725 m per year), and the LRR (+154.386 m per year). Also, an analysis of land area changes during the 20152019 period resulted in the Kalisari Village experiencing the most significant accretion of 358073.62 m2, while in Keputih Village abrasion of 30189.72 m2.