A Conceptual Model for Semarang City Sustainability

Coastal site is a very strategic area, proven by the fact that 70% of big cities in the world are located in coastal areas or precisely in coastal areas. Coastal are also has a high level of sensitivity to natural phenomena such as tsunami, tidal floods, strong sea winds, or abrasion. Semarang City is one of the coastal cities with high vulnerability, especially from the tidal flood caused by rising sea levels and land subsidence. Kota Lama/historical area is an area directly adjacent to the coast of Semarang City. This area is the first site affected by the tidal flood that often occurs in Semarang City. This research aims to provide an alternative model for the sustainability of cities in the coastal area through a protection approach to historic areas as a factor of resilience to the city. The method used to produce the model is overlaying technique using ArcGIS software. The variables used in this study are physical and social factors. The physical factors consist of the slope of the coast, the maximum tidal range, average wave height, sea-level rise, beach geomorphology, coastline changes, and land subsidence. Social factors consist of population density, land use, population age, and education level. All variables are given a weight according to their respective criteria by the weighted overlay method. The next step is the process of adding the weights of each variable using simple mathematical operations using the sum tools. The final stage to obtain the vulnerability index distribution zone is carried out reclassification to show its spatial distribution. The results show that the Kota Lama Region is proven to have contributed to the formation of City resilience.