The study of SSC patterns on coastline changes in Socah Gulf using Landsat imagery and in-situ data

Socah as an economical buffer in Surabaya Metropolitan Area becomes one of important sub-districts in Bangkalan. As a shallow coast, this area is predicted to have significant coastline changes and a unique sedimentation pattern. This research aimed to analyze the sedimentation pattern and coastline changes in Socah. The 30 m of Landsat imagery was used in this research to observe sedimentation pattern that is represented by a suspended sediment concentration (SSC) trend from 2013, 2015, and 2018. Landsat images were also used to monitor the coastline changes in Socah starting from 1994 to 2018. From the sea color analysis, SSC values in rainy season are higher than those in dry season. The difference of SSC average between two seasons, in three stations, is 127 mg/L. SSC values in 2018 is also higher than those in previous years, with difference up to 94,17 mg/L in dry seasons and 357,67 mg/L in rainy seasons. Based on coastal changes calculation in the MHWL position from 1994 to 2018, the coastline changes in Socah reaches +5,325 m at a rate of about 0,26 m/yr. Coastline changes in Socah cause the area increase in 2018 up to 3,534 ha or 0,06% bigger than that in 1994. Those changes are dominated by accretion in Junganyar, Buluh, and Penarjuh Villages.