Monitoring Coastline Changes Using Landsat Application in Batu Mejan Beach

Monitoring Coastline changes is a very important task to assess and evaluate the condition of the coastal area. Accurate results of changes in coastline are very useful as a consideration in making decisions for coastal area management and planning for future coastal development. Therefore, coastline changes, both erosion and accretion were examined in this study. Batu Mejan Beach is selected as a study area. It is a tourism destination often visited by foreign and local tourists in North Kuta Beach. Its current condition is very poor because of the erosion that has occurred. The government has tried to build a sea wall for protection, but the structure has failed. Remote sensing is a method that can monitor shoreline changes more efficiently than taking measurements directly into the field. With the remote sensing method, changes in the shoreline at a certain period can be investigated. The remote sensing analysis method is used to extract coastlines from Landsat 7 satellite images in 2002 and Landsat 8 in 2018. Landsat was analyzed using a combination approach of threshold and band ratio methods of infrared bands and green bands. Image processing uses ENVI 5.3 software and ArcGIS 10.4.1 with the Quoted Shoreline Analysis System (DSAS) extension to make transect shoreline calculations. The results of the analysis of the rate of change in the coastline along Batu Mejan Beach showed abrasion of 0.11-5.14 m/year and accretion of 0.29-0.84 m/year.