Spatial-Temporal Distribution and Vulnerability Level of Tidal Flooding in the Coastal City of Semarang.

As a city located in the northern coast of Central Java, Semarang continuously faces serious challenges related to annual tidal flooding. This research specifically examines the multi-temporal distribution of tidal floods in the 2020-2024 time span. Using the Change Detection method on Sentinel-1 SAR satellite imagery, the distribution of tidal flooding during this period was determined. The data obtained was then further processed with overlay techniques to produce more detailed information. This technique allows for mapping areas with different levels of tidal flood vulnerability, and the overlay results were used as one of the parameters in the Composite Mapping Analysis (CMA) method, which integrates various related parameters. The results point out that the coastal areas of Semarang City, including the sub-districts of Tugu, West Semarang, North Semarang, East Semarang, Gayamsari, and Genuk, are dominated by high vulnerability levels. These areas have a high vulnerability percentage of 40%, covering an area of 4,988.65 hectares. Medium vulnerability includes 33% of the area with 4,080.01 hectares, while low vulnerability covers 23% with 2,802.22 hectares. Areas with very high vulnerability only incorporates 3.9% with an area of 481.40 hectares, and the lowest is very low vulnerability at 0.1% with an area of 10.39 hectares. The sub-districts most affected by high vulnerability are Genuk, Tugu, West Semarang, North Semarang, Gayamsari, and East Semarang in succession. [ABSTRACT FROM AUTHOR]