ASSESSMENT OF MANGROVE AS A NATURAL BEACH PROTECTION IN SURABAYA COAST, INDONESIA.

Mangrove area in east coast of Surabaya region is becomes a fortress to protect the city from the threat of erosion and sea intrusion. According to its function, the development of mangrove areas will help this area in dealing with coastal erosion. This study presents a GIS model that aims to determine the effect of mangrove changes to coastal erosion risk. The method used Landsat satellite images during 2015-2019 to calculate mangrove changes. DSAS (Digital Shoreline Analysis System) is used to calculate shoreline changes. Finally, the model used CERA to analysis coastal erosion risk. The results showed that there is the dynamics change of shoreline (both accretion and abrasion) in the 2015-2019 period in each district. This change is influenced by the density of mangroves. Meanwhile, the analysis of CERA showed that the Kenjeran and Bulak Districts are classified as high risk of erosion. This condition is not only based on the extent of mangrove but is also caused by other parameters such as geomorphology, land cover, population density, and so on. [ABSTRACT FROM AUTHOR]