Modeling of Flood Vulnerability Level of Pontianak City Iin Arianti1, Muhammad Rafani1*
1Department of Civil Engineering, Politeknik Negeri Pontianak, Indonesia
*Corresponding author r4f4n1[at]yahoo.com
Abstract
This research was conducted to establish a vulnerability model of flood hazard in the city of Pontianak, West Kalimantan Province used GIS. The model was based on scoring and weighting of biophysical factors. The AHP (Analytic Hierarchy Process) method and logical formulations were used to establish the model. The result showed that the accuracy of model by AHP to determine the vulnerability of flood was only 80% in Pontianak City. Therefore the model was not good enough to represent actual condition in the field. The accuracy of model using logical formulations to determine the vulnerability level of flood was 84%, this means that the results of model 1 have a confidence level of 84% after checking the location of inundation points on the map against inundation points in the field. The Kappa accuracy value in model 1 is 79.3%, this means it is able to avoid 79.3% errors. The model of flood vulnerability (model 1) explains that most of Pontianak City has a very high level of flood vulnerability, which is 31,440,568.8 m2 or 29.11% of the total research area of 108,003,319.8 m2. The vulnerable area is 29,945,485.7 m2 or 27.73% and the less secure area is 22,126,936.3 m2 or 20.49% and the safe area is 24,490,328.7 m2 or 22.67% of the total area. Sub-districts that have the most area in a very flood prone area in a row are City Pontianak Sub-district covering 8,299,516.9 m2- then followed by South Pontianak Sub-district covering an area of 6,980,141.8 m2- West Pontianak Sub-district covering an area of 5,638,021.4 m2- North Pontianak Sub-district covering an area of 4,095,410.0 m2- Southeast Pontianak Sub-district covering 3,830,011.8 m2- and the Sub-district of East Pontianak covering 2,597,441.2 m2.
