Application of Flood Modeling in Informal Settlement Areas in Makassar City, Indonesia

The Spatial and Regional Plan (RTRW) of Makassar City 2015-2034 does not cover the Mariso and Mamajang Sub-districts in flood-prone areas, even though both districts have experienced flooding.To investigate this issue, this research focuses on flood modeling-based flood modeling.The aim of this research is to identify the existing spatial conditions in the research area by conducting flood simulation modeling in both districts and analyzing the spatial impact of flood modeling on informal settlement areas.The research was conducted over four months, from April to July 2023.The data used includes primary and secondary data obtained from government agencies and field observations.Spatial data includes actual flood areas, land cover, and DEM-NAS, while non-spatial data involves rainfall and tidal data.The research methods include qualitative and quantitative analyses.Spatial analysis is used to analyze the distribution of flood areas, elevation conditions, rainfall, land cover, informal settlement areas, and flood model maps.Meanwhile, quantitative analysis involves data analysis in tabulation and graphs, such as rainfall intensity, tidal data, Manning's roughness coefficient, runoff values, and the number of pixels in the flood model.The research results include four main pieces of information: an existing area analysis identifying 125 flood areas.The elevation of the coastal area is generally low, with the highest elevation on land reaching 23 meters.There are 11 types of land cover, and rainfall falls into the moderate to high category.Flood modeling results in macro and micro, simulations in terms of water levels and flood flow.Validation results show a modeling accuracy level of 69.03%.Meanwhile, the spatial impact of flood modeling results in 60 flood distribution areas with varying heights between 10 cm and 300 cm, with informal settlement areas behind the most affected.This research provides information to understand the flood characteristics in informal settlements in the Mariso and Mamajang Sub-districts of Makassar City through a comprehensive flood modeling-based approach.