Sedimentation Analysis towards the Changes of Mangrove Area Using Multitemporal Remote Sensing Technology (Case Study: Gresik Regency)

Mangrove grows in coastal areas with the soil is resulted from the accumulation of mud substrate from the sedimentation process. Gresik Regency is a downstream area where the Bengawan Solo River flows and there is the Java Sea that carries a lot of sediment material to the coast. As a result, there is sedimentation that is forming new land increasingly that can be a place for mangroves to live. Therefore in this study, the calculation of suspended sediment concentration and mangrove area in Gresik Regency during 2016-2019 is using Sentinel-2A satellite imagery. The purpose of these calculations is to determine the effect of sedimentation as suspended sediment on changes in the mangrove area. Mangrove area is obtained from the Maximum Likelihood supervised classification. While suspended sediment concentrations estimated from remote sensing data are obtained using four prior algorithms but those do not meet the specified accuracy requirement. This research shows that there have been changes in the mangrove area in the form of increasing and decreasing during 2016-2019. The largest addition of area occurred in the period 2016-2017 which is 479.347 Ha and the most reduction in the area occurred in the period 2018-2019 which is 534.087 Ha. The statistical test result proves that the suspended sediment as sedimentation affects the mangrove by 64.9% in the significance level of 5% or 95% confidence level.